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Why does vinegar made from wine contain only about half as much acid as the original alcohol?

Why does vinegar made from wine contain only about half as much acid as the original alcohol?



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It is my understanding that the fermenting bacteria process the alcohol into acetic acid. But why is it about half the percentage of volume? For example table wine is often 12% ethanol, but vinegar is generally about 5% acetic acid.


Exploring Enzymes

Introduction
Have you ever wondered how all the food that you eat gets digested? It is not only the acid in your stomach that breaks down your food&mdashmany little molecules in your body, called enzymes, help with that too. Enzymes are special types of proteins that speed up chemical reactions, such as the digestion of food in your stomach. In fact, there are thousands of different enzymes in your body that work around-the-clock to keep you healthy and active. In this science activity you will investigate one of these enzymes, called catalase, to find out how it helps to protect your body from damage.

Background
Enzymes are essential for our survival. These proteins, made by our cells, help transform chemicals in our body, functioning as a catalyst. A catalyst gets reactions started and makes them happen faster, by increasing the rate of a reaction that otherwise might not happen at all, or would take too long to sustain life. However, a catalyst does not take part in the reaction itself&mdashso how does this work? Each chemical reaction needs a minimum amount of energy to make it happen. This energy is called the activation energy. The lower the activation energy of a reaction, the faster it takes place. If the activation energy is too high, the reaction does not occur.

Enzymes have the ability to lower the activation energy of a chemical reaction by interacting with its reactants (the chemicals doing the reacting). Each enzyme has an active site, which is where the reaction takes place. These sites are like special pockets that are able to bind a chemical molecule. The compounds or molecules the enzyme reacts with are called their substrates. The enzyme pocket has a special shape so that only one specific substrate is able to bind to it, just like only one key fits into a specific lock. Once the molecule is bound to the enzyme, the chemical reaction takes place. Then, the reaction products are released from the pocket, and the enzyme is ready to start all over again with another substrate molecule.

Catalase is a very common enzyme that is present in almost all organisms that are exposed to oxygen. The purpose of catalase in living cells is to protect them from oxidative damage, which can occur when cells or other molecules in the body come into contact with oxidative compounds. This damage is a natural result of reactions happening inside your cells. The reactions can include by-products such as hydrogen peroxide, which can be harmful to the body, just as how a by-product of a nice bonfire can be unwanted smoke that makes you cough or stings your eyes. To prevent such damage, the catalase enzyme helps getting rid of these compounds by breaking up hydrogen peroxide (H2O2) into harmless water and oxygen. Do you want to see the catalyze enzyme in action? In this activity you will disarm hydrogen peroxide with the help of catalase from yeast.

  • Safety goggles or protective glasses
  • Five teaspoons of dish soap
  • One package of dry yeast
  • Hydrogen peroxide, 3 percent (at least 100 mL)
  • Three tablespoons
  • One teaspoon
  • Five 16-ounce disposable plastic cups
  • Tap water
  • Measuring cup
  • Permanent marker
  • Paper towel
  • Workspace that can get wet (and won't be damaged by any spilled hydrogen peroxide or food-colored water)
  • Food coloring (optional)

Preparation

  • Take one cup and dissolve the dry yeast in about one-half cup of warm tap water. The water shouldn't be too hot but close to body temperature (37 Celsius). Let the dissolved yeast rest for at least five minutes.
  • Use the permanent marker to label the remaining four cups from one to four.
  • To all the labeled cups, add one teaspoon of dish soap.
  • To cup one no further additions are made at this point.
  • Before using the hydrogen peroxide, put on your safety goggles to protect your eyes. In case you spill hydrogen peroxide, clean it up with a wet paper towel. If you get it on your skin, make sure to rinse the affected area with plenty of water.
  • To cup two, add one tablespoon of 3 percent hydrogen peroxide solution. Use a fresh spoon for the hydrogen peroxide.
  • To cup three, add two tablespoons of the hydrogen peroxide.
  • To cup four, add three tablespoons of the hydrogen peroxide.
  • Optionally, you can add a drop of food color to each of the labeled cups. (You can choose a different color for each one for easy identification)
  • Take cup number one and place it in front of you on the work area. With a fresh tablespoon, add one tablespoon of the dissolved yeast solution to the cup and swirl it slightly. What happens after you add the yeast? Do you see a reaction happening?
  • Place cup number two in front of you and again add one tablespoon of yeast solution to the cup. Once you add the enzyme,does the catalase react with the hydrogen peroxide? Can you see the reaction products being formed?
  • Add one tablespoon of yeast solution to cup number three. Do you see the same reaction taking place? Is the result different or the same compared to cup number two?
  • Finally, add one tablespoon of yeast solution to cup number four. Do you see more or less reaction products compared to your previous results? Can you explain the difference?
  • Place all four cups next to each other in front of you and observe your results. Did the enzymatic reaction take place in all of the cups or was there an exception? How do the results in each cup look different? Why do you think this is the case?
  • Now, take cup number one and add one additional tablespoon of 3 percent hydrogen peroxide to the cup. Swirl the cup slightly to mix the solution. What happens now? Looking at all your results, what do you think is the limiting factor for the catalase reaction in your cups?
  • Extra: Repeat this activity, but this time do not add dish soap to all of the reactions. What is different once you remove the dish soap? Do you still see foam formation?
  • Extra: So far you have observed the effect of substrate (H2O2) concentration on the catalase reaction. What happens if you keep the substrate concentration constant but change the concentration of the enzyme? Try adding different amounts of yeast solution to three tablespoons of hydrogen peroxide, starting with one teaspoon. Do you observe any differences, or does the concentration of catalase not matter in your reaction?
  • Extra: What happens if the environmental conditions for the enzyme are changed? Repeat the catalase reaction but this time vary conditions such as the pH by adding vinegar (an acid) or baking soda (a base), or change the reaction temperature by heating the solution in the microwave. Can you identify which conditions are optimal for the catalase reaction? Are there any conditions that eliminate the catalase activity?
  • Extra: Can you find other sources of catalase enzyme that you could use in this activity? Research what other organisms, plants or cells contain catalase and try using these for your reaction. Do they work as well as yeast?

Observations and results
You probably saw lots of bubbles and foam in this activity. What made the foam appear? When the enzyme catalase comes into contact with its substrate, hydrogen peroxide, it starts breaking it down into water and oxygen. Oxygen is a gas and therefore wants to escape the liquid. However, the dish soap that you added to all your solutions is able to trap the gas bubbles, which results in the formation of a stable foam. As long as there is enzyme and hydrogen peroxide present in the solution, the reaction continues and foam is produced. Once one of both compounds is depleted, the product formation stops. If you do not add dish soap to the reaction, you will see bubbles generated but no stable foam formation.

If there is no hydrogen peroxide present, the catalase cannot function, which is why in cup one you shouldn't have seen any bubble or foam production. Only when hydrogen peroxide is available, the catalase reaction can take place as you probably observed in the other cups. In fact, the catalase reaction is dependent on the substrate concentration. If you have an excess of enzyme but not enough substrate, the reaction will be limited by the substrate availability. Once you add more hydrogen peroxide to the solution, the reaction rate will increase as more substrate molecules can collide with the enzyme, forming more product. The result is an increasing amount of foam produced in your cup as you increase the amount of H2O2 in your reaction. You should have seen more foam being produced once you added another tablespoon of hydrogen peroxide to cup one, which should have resulted in a similar amount of foam as in cup two. However, at some point you will reach a substrate concentration at which the enzyme gets saturated and becomes the limiting factor. In this case you have to add more enzyme to speed up the reaction again.

Many other factors affect the activity of enzymes as well. Most enzymes only function under optimal environmental conditions. If the pH or temperature deviates from these conditions too much, the enzyme reaction slows down significantly or does not work at all. You might have noticed that when doing the extra steps in the procedure.

Cleanup
Pour all the solutions into the sink and clean all the spoons with warm water and dish soap. Wipe your work area with a wet paper towel and wash your hands with water and soap.

This activity brought to you in partnership with Science Buddies


Vinegar: Its History and Development

This chapter discusses the history and development of vinegar. Vinegar is one of several fermented foods prepared and used by early man and like others, wine, beer, bread, and certain foods from milk, its discovery predates the earliest historical records. The word “vinegar” is derived from two French words, “vin” and “aigre” meaning sour wine, but the term is now applied to the product of the acetous fermentation of ethanol from a number of sources. Vinegar has played an important but little-emphasized role as a food adjunct in man's development of his civilization. Production methods and improvements developed slowly and empirically for centuries, and only in the last few years have they benefited from the application of the scientific method. Vinegar was prepared by the Babylonians from the juice or sap of the date palm, from date wine and raisin wine, and from beer. Vinegar was used by the Babylonians in cooking, along with spices, to enhance what at times undoubtedly was a monotonous diet. Cheaper automated fermentor and a workable automated continuous process for vinegar are likely developments in the future.


Why does vinegar made from wine contain only about half as much acid as the original alcohol? - Biology

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The History of Marquis by Waterford Crystal

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About Crystal Classics

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Rhubarb Wine Recipe

Equipment

Ingredients

Fermenting

  • 5 lbs Rhubarb 2.3 kg
  • 3 lbs Sugar 1.4 kg
  • 1¼ cups Black tea 285 ml
  • 3 quarts Water 2.8 liters
  • 2 tsp Yeast nutrient
  • 1 sachet White wine yeast 5 g

For after fermentation

To sweeten the wine

Instructions

Prepping the rhubarb

Initial fermentation

Second Fermentation

Aging the wine

To sweeten the wine

Rack the wine into bottles

Nutrition

Tried this recipe? Let us know how it was!


Contents To The Ultimate Guide For Decanting Wine

Why Do You Decant Wine?
Preparation for Decanting Wine
Full Method on How to Decant Wine
How To Decant Wine Without A Decanter
Summary On Wine Decanting

Why Do You Decant Wine?

We decant wine for two main reasons, to remove sediment and to aerate the wine but there are also additional benefits. Why do we decant red wine is a finer question, as the full process of decanting only applies to red wine. People have different occasions for decanting wine, it could be an every day occurrence, for dinner parties or for a bigger occasion such as a wedding.

Remove Bottle Stink From A Wine Bottle

Many young wines develop a strong egg smell due to the sulphur preservatives this is a minor fault when the wine yeast doesn’t get enough nutrients while fermenting. This smell can drastically ruin the taste of your wine or your experience overall, as the shape of a wine glass is designed to guide the notes directly to your nose. You should ensure to decant these wines to eradicate this smell. This smell can also be removed by stirring the wine with a Sterling Silver spoon.

Removing Sediment From Wine

A wine that has aged in the bottle, typically red as opposed to white will drop sediment. This thick substance is a combination of all the different particles of ingredients within the wine coming together and settling at the bottom of the bottle. This sediment is both ugly to have floating around in your glass and unpleasant in the mouth. It can form bits and cause staining to worsen. These aged red wines are those most deserving of decanting.

Aerating Wine

Aeration is the act of getting the air in contact with the wine and oxidising it so that the flavours can fully develop – however be warned, leaving your wine to aerate for too long can turn your wine into vinegar, and once it is dead you cannot bring it back.

You may want to aerate a young wine (10 years or less) if the taste is too strong or too tarty, aeration for up to 30 minutes will provide you with a much smoother and complex taste. The aeration time varies for all wines, and there is no solid rule that applies to all. However it is strongly advised to periodically taste the wine throughout the aeration process, and once you feel the wine is ready – drink it! The wine will continue to develop in the glass.

The wine decanter, also known as the carafe, is designed specifically to aid the aeration process. Traditionally they have wide bottoms with a large surface area which exposes more of the wine to the air to create a quicker result. If you are not intending on serving your wine immediately after decanting, you should ensure that your carafe has some kind of stopper so that no delicate flavours or aromas are lost. It is okay to swirl and shake your decanter as this gets more air into the wine.

When pouring from the bottle into the decanter however, it is advised to pour at a 45 degree angle against the opposite side the decanter neck, allowing it to follow the curves of the glass so it doesn’t froth the surface of the wine. Removing the cork but leaving the wine in the bottle also begins the process, but at a much slower rate and is potentially much riskier, as the air only makes contact with a very small surface area. By the time the air reaches the bottom of the bottle, the wine at the top could have become oxidised, or turned to vinegar.

How To Tell If the Wine Is Ready

The one hard rule of wine decanting is that if it tastes right, drink it! A good wine will only deteriorate if left too long and you cannot bring it back. If you cannot taste much fruit, it is overly tannic or you are struggling to identify any aromas then the wine is “closed” and will need decanting. If the wine is ready it will be noticeably smoother and more pleasant. There should be the scent of fruit flavours and you will know it is ready because of your control wine, taken from the start of the decanting process to compare with.

Preparation For Decanting Wine

What You Will Need For Decanting Wine

  • A good quality, clear wine carafe
  • Your wine of choice
  • Candle or flash light
  • Corkscrew
  • Sharp knife

What Does A Decanter Do?

A crystal decanter is a vessel to hold liquid in, particularly alcoholic drinks like whisky and wine. Each decanter is crafted to a specific design to specifically aid an individual liquid, so it is important that you get a decanter which suits your needs. In this article you will hear me use the terms decanter and carafe – a carafe, compared to a decanter, is a decorative vessel to hold the liquid in and is used for more than just wine such as water or soft drinks.

Storing Wine

The temperature wine is kept at is more important than most people think. Cold temperatures slow the rate of fermentation but extremely cold air can increase the acidity of red wines which are high in tannic acid. Warm air can cause the wine to mature too quickly and not keep long. Temperature changes also affect the wine, so do not store in an area where temperature fluctuates as this can accelerate ageing and reduce lifespan.

  • Avoid high places as heat rises.
  • Store in a cool, dark, unused place to reduce disturbances.
  • Store champagne in a refrigerator.
  • White wine, Rosé, Sparkling wine and dessert wine lose flavour when kept in a refrigerator for too long, but the tastes are enhanced when served chilled. The best method is to avoid storing them in the refrigerator, but to chill them in the refrigerator for only a few hours before serving.
  • Store wine horizontally, keeping the corks moist. This makes them swell and stops air and bacteria from entering the bottle.
  • Allow space between the storage of bottles as the vibrations promote a sour taste as dead yeast cells in the sediment are unable to settle.
  • Avoid sunshine or ultraviolet light as this will give wine a flat or musty flavour.
  • Humidity levels should be at a minimum of 74%, however anything over 95% will promote mould.

Wine Storage Temperatures

  • White wine, Rosé and Sparkling wine are stored at cooler temperatures than red wines.
  • Wine stored in the ambient temperature of 20 to 21 degrees Celsius (68 to 70F) will keep for several months.
  • Red wine tastes better when served slightly below room temperature.
  • White wine tastes great from about 44 – 57 °F.
  • Sparkling wine do best at 38 °F – 45 °F
  • Warmer wine, typically above 70F will begin to smell more alcoholic because of the increased ethanol evaporation.

First you will need to take your bottle of wine from wherever it has been stored, preferably somewhere dark and cool where it is not frequently disturbed or moved. You will want to stand the bottle upright for at least a few hours to allow the sediment to settle at the bottom of the bottle.

Ensure your carafe is clean and free of all dust or anything that could affect the flavours or nose of your wine. You should never wash your carafe with detergent or soaps, instead use a mix of crushed ice and coarse salt to remove any residue wine and simply rinse with hot water. If you are not convinced by this method, you can give it a cycle in the dishwasher but without any detergent or soap powder. It is then advised that you rinse with mineral water to remove any odours it may have picked up. When opening the bottle, you want to remove the entire capsule around the neck with a sharp knife. Removing any metal or plastics will ensure you have no obstructions when watching for sediment whilst decanting.

It is traditional to cut the foil from the bottom lip because foils were previously made out of lead, this method reduces stray drips. Foil cutters, however, are designed to cut the top of the lip. Cutting the top lip is more visually appealing and ideal for moments where the wine is on display. Even when decanting it is advisable to present the bottle at the table for guests to refer to. When removing the cork, aim the corkscrew just off centre of the cork, this will make the radial diameter of the “worm” (the screw) centred, making it less likely to tear or break. The corkscrew should be inserted one turn less than all the way into the cork. Following this should ensure you do not break the cork.

If Decanting Champagne or Sparkling Wine

Many people decant champagne or sparkling wine to reduce the bubbles so that they can fully appreciate the taste. Removing the cork from the bottle often causes the cork to compress against the glass, create pressure and this makes the wine fizz up from the bottle, often losing a lot of the wine in the process. Instead there is a simple way to open the bottle to avoid this.

  • Remove the top covering of foil.
  • Twist the metal loop attached to the wire muzzle to the left.
  • Remove the Muzzle.
  • Hold the bottle firmly around the neck.
  • To prevent the cork from shooting out from pressure, hold it in place with your thumb.
  • Hold the bottle in one hand and with the other hand turn and loosen the cork.
  • Cover the bottle with a napkin to absorb any wine that may escape in this process.
  • A tilted bottle of sparkling wine moves pressure away from the cork and puts it against the side of the bottle. Hold the bottle at a 45-degree angle towards a clear area.
  • Push the cork upward with the thumb, and gently ease it from the bottle.
  • The cork should expel with a soft sigh, rather than a loud bang.

Should You Decant White Wine?

White wine contains less tannin than red and so does not last as long but many people decant white wine to reduce the bubbles, giving them a better experience of the wines flavours. A white wine’s delicate aromas and flavours can be ruined by being oxidised and as this occurs quite quickly, it is advised to keep aeration to a minimum. Since white wine drops very little if no sediment, there is little need to go through the process of separation. A sharp, tight white wine could benefit from some aeration of up to 30 mins taste periodically to ensure you do not end up drinking vinegar. So yes, you can decant white wine with some caution and care, but check with your guests first as they may enjoy the bubbles!

Can You Decant Rosé?

In all my searches across the web I have never been able to find a solid answer to this question, but from numerous tests, trials and tribulations I can safely say do not decant Rosé. Rosé has a lively, fruity palette that is already celebrated for its pleasant taste, aerating it would only damage its already delicate composition. If you would like to present your Rosé in a carafe at the table however, you could pour the Rosé into the carafe just before serving after being chilled for several hours. There is no need to remove sediment and the simple act of transferring from bottle to carafe is enough aeration for this particular drink, be warned however, as once transferred to a carafe it is unlikely that the Rosé will keep overnight without being refrigerated. Many people believe Rosé to be a modern revolution and a combination of red wine and white wine but is notably one of the oldest known types of wine. Rosé wines can be made still, semi-sparkling or sparkling and with a wide range of sweetness levels from dry Provençal rosé to sweet White Zinfandels and blushes. Rosé wines are made from a wide variety of grapes and can be found all around the globe.

Full Method For Decanting Wine

Removing the Sediment

  • Uncork your wine or remove stopper or lid.
  • Before you decant your wine, pour a small glass to taste the wine to assess the length of time it will need.
  • Pour slowly at a 45 degree angle from bottle into carafe, guiding the stream to hit against the opposite side of the carafe neck so that it gently flows over the glass curves, avoiding frothing the surface. Use the light source to locate the sediment and avoid pouring sediment into the carafe but do not heat the wine as you decant it as wine is sensitive to temperature.
  • Once you have tipped the wine bottle up enough that the sediment reaches the shoulder of the bottle, it is time to stop. However if you feel you could get more from the bottle you can always allow the wine to sit for a while so that the sediment settles once more and try again in a few hours. Unfortunately it is more than likely that this sediment will not separate from the wine. A popular choice is to use a coffee filter, though this can harm the wine and remove too much substance and upset the balance of the flavours.
  • The end result of your decanting process should be a carafe full of clear wine, with half a glass of the sediment laden wine left within the bottle. This remaining wine is a great cooking ingredient, so be sure not to waste it.

How to Wine Taste

Wine tasting at home is great it can make you feel at ease and superior all at the same time – full of confidence! Wine carafes are a great thing to have around your home for storing your decanted wine as it oozes sophistication before you even start on the plonk. You can have your glass wine decanters, silver wine goblets and crystal red wine glasses all on presentation together for the full effect when hosting your own wine tasting parties at home. The following simple steps will teach you how to taste wine properly, and once you know how to wine taste you will be able to fully appreciate the effects of decanting. Why decant red wine, or why do you decant wine of any kind will become apparent to you. Be sure to pass your wine tasting tips onto your friends too – but not in a pretentious kind of way! A wine tasting party at home may sound like a great idea at first, but be sure to know how long to decant wine for before hosting a home wine tasting party as this could be disastrous if you don’t really know what you are talking about. Study before hand and always practice, doing is always the best way on how to learn about wine. Take a small taste of the wine to check the starting flavours and asses how long it will need to aerate, see below our list of pointers on how to detect the different flavours and properties of your wine:

  • Pour into the proper wine glass for the type of wine you will be decanting.
  • Look – hold the glass up against a white background to evaluate its colour and clarity. Red wine fades with age, white wines darken with age. Wine that is discoloured or cloudy may be bad or off. If the wine is brown it may have been exposed to too much heat at one point.
  • Swirl – Swirling the wine will allow it to oxidise just enough to release its aroma.
  • Smell – Put your nose in the glass and take a deep breath. Older wines should have subtler scents than younger ones note that delicate fruity aromas will dissipate quickly with decanting than full bodied wines. Investigate the smell of any wet cardboard or mustiness, this tells you that the wine is “corked”, meaning the cork has been tainted. If your wine smells decayed then it could be from the grapes yeast getting into the wine.
  • Taste – Fill your mouth ½ full and swish the wine. This should release its aroma and coat your mouth and will give you a final judgement on whether the wine needs decanting for a longer or shorter period of time. If the wine tastes dull or cooked it may have oxidised, making it taste and smell like vinegar and turn discoloured.

Aerating Your Wine

  • Swirl the wine within the carafe and then leave for approximately 30 minutes, checking back periodically to taste and assess the development stage.
  • When it tastes right to you – serve and enjoy! Remember, if you leave a wine to decant for too long, you can never bring it back and you will get a harsh vinegar taste. The length of time to aerate varies for each wine, so coming back to taste every so often is an important step. It is always better to get the wine close to perfect and then continue developing in your glass while serving.

Wine Serving Etiquette

Ensure you have the appropriate stemware for your chosen wine, quality crystal wine glasses are ideal. Good, all purpose stemware should have these four important characteristics:

  • A clear bowl, so that you can observe the wines colour and condition
  • A long stem, so that the warmth of your fingers does not heat the wine.
  • A thin rim, to make sipping easy and dribble free.
  • A wide capacity, so that you have the room to safely swirl the wine.

Red wine glasses have a larger bowl so that it can fit in your palm and gently be warmed by your hand. Red wine should be filled to 4 ounces in the glass, or a half glass full. These glasses can commonly be found in a wine gift set, or more specifically a red wine glass set. When decanting red wine, the red wine in your glass should appear clear with no sediment. White wine glasses have a longer stem and a more slender bowl than red wine glasses to keep the heat from your fingers away from the wine, keeping it as cool as possible for longer. The slender bowl helps to maintain the wines liveliness. You should fill your glass with 3 ounces per glass or one third full. White wine glasses are a great gift for special occasions so can normally be found as wine glass sets. Champagne and sparkling wines are served in flutes which are a much narrower shape to preserve the bubbles and directs them up the glass. The glass should be filled three quarters full, or 4 ounces. These fine crystal wine glasses also come in a wine glasses set or a flutes set. Some people use a glass wine decanter for champagne and other bubbly wines, to reduce the fizz so they can get more out of the flavour you should experiment with using different types of crystal wine glass when removing the bubbles to experience the best of the wines aromas and flavours. It is best to present the empty wine bottle at the table with your decanter as guests will often like to refer back to the bottle.

Leftover Wine

It is advised to re-cork the bottle or seal the decanter in some way and putting it in the refrigerator. This will slow down the ageing process that spoils the wine both for red and white wines. Add marbles to an open bottle or decanter that is only half full until the wine is brought to the top to get rid of air reseal and refrigerate. White wine is the least durable to keep after being opened red wines that are high in tannins however are considerably more durable.

How To Decant Wine Without A Decanter

Sometimes you won’t have all the equipment you need to decant wine, so there are some ways to get a similar effect. Hopefully some of the below ideas will show you how to decant wine without a decanter.

Double Decanting With Wine

  • Decant as normal from the wine bottle to the carafe.
  • Wash the bottle with clean water to remove all traces of residue wine and sediment.
  • Pour the wine back into the wine bottle with the same decanting method and re-cork.
  • The double decanting method adds more air to the wine because it is exposed to the air twice, enabling a faster development time.

Blender Decanting With Wine

  • Pour the wine into the blender the same way you would with a decanter to reduce the sediment.
  • When you are ready to serve, blend the wine on the highest power for 30 to 60 seconds.
  • Allow the froth to subside then serve. You could pour the wine into a decanter to present at the table for appearance purposes.
  • Hyper-decanting (wine in a blender) has been shown to greatly improve the aromas and flavours on bold red wines as well as affordable wines.
  • Myhrvold’s Theory (below) began the “Hyper Decanting” trend and Wine Searcher goes into greater depths with this insightful interview.

Wine lovers have known for centuries that
decanting wine before serving it often
improves its flavor. Whatever the dominant
process, the traditional decanter is a rather
pathetic tool to accomplish it. A few years
ago, I found I could get much better results
by using an ordinary kitchen blender.”

— Nathan Myhrvold

Use an Aerator On Wine

  • A wine aerator is a small glass tool fitted to the end of a wine bottle or the top of your wine glass to filter air through the wine.
  • Push a fitted aerator deep into the neck of the wine bottle securely so it will not fall out when pouring.
  • Simply pour the wine as though you were pouring directly into a glass, allowing the wine to filter through the aerator. These are exceptionally simple devices that are self-explanatory no matter what design you end up with.
  • Allow the wine to sit in the glass for as long as possible. It is because of this last step that makes decanting before the meal more appropriate than making your guests wait before they can enjoy their already poured glass of wine.
  • Wine aerators are faster than decanters but are not advisable for aged wines or removing sediment.

Summary On Decanting Wine

My personal preference is to open, decant and serve the wine within an hour, as I find that older wines tend to fade much quicker than younger wines. However wine is all about personal preferences, and with no solid rules it is hard to give a solid answer on how long to decant your wine for. Sometimes you may not be able to find out if your wine was aged in oak and needed to be decanted for that reason, or you may be inexperienced at wine tasting and don’t know how to fully take advantage of the processes. It is known though that strong flavoured wine like Bordeaux Blends, Cabernet Sauvignon, Malbec and Rhône wines will endure decanting well, whereas delicate aromatic wines such as Rosé and sweet whites will not. My suggested period of decanting for wines less than fifteen years old should be approximately 30mins. If your wine is 15-30 years old, gentle and careful decanting of half to a full hour is usually more than enough as they have already aged. For even older wines, you should decant just before serving.

To finish off this blog post, enjoy this brilliant video by The Professional Culinary Institute with Master Sommelier David Glancy, as he decants a mature red wine:


All content from this article has been originally produced by Kate Robinson and is her property. Original blog post can be found at Silver Groves.

Satisfaction Guaranteed Money Back Guarantee We're so confident in the quality of our wines that we guarantee every bottle. If you don't like a wine, for any reason, you'll be refunded in full. It's simple.


First, Select the Right Pot

One thing to keep in mind right away is not to try to cram too much fruit into your jam pot. The mixture needs room to bubble up while it's heating in order for the water to evaporate and the pectin web to form. I try to fill the pot less than half full of the jam mixture—that's all the fruit and sugar and lemon juice mixed together (and you'll want to mix them together before dumping them into your jam pot if you're using copper read about why in my installment on jamming gear). Just as an example, my pot is about 15-inches across, 4.5-inches deep, and has an 11-quart capacity, and I can usually fit between 5 and 6 pounds of fruit without overfilling it.


Why does vinegar made from wine contain only about half as much acid as the original alcohol? - Biology

I was inspired by coaching one of my coworkers through his first batch of homebrew (an English bitter) to write up a list of the mistakes that many new homebrewers make. Several of these are things I did on early batches, while others I have tasted at homebrew at club meetings. Many of these issues stem from poor kit instructions, bad homebrew shop advice, and common sense that just doesn’t work out.

1. Using the sanitizer that comes with a beer kit. This powdered sanitizer is slow and not especially effective. Instead get a no-rinse sanitizer like Star-San or Iodophor, which are faster and easier to use. Sanitize everything that touches your beer post-boil, and make sure it is carefully cleaned after each use (sanitizers are most effective on scrupulously-clean scratch-free surfaces). Keeping wild microbes out of your beer is the single most important step to brewing solid beer.

2. Starting with a recipe that is strong or unusual. Brewing a big complex beer is lots of fun, but play it safe on your first batch and brew something simple. High alcohol beers require more yeast and time. Interesting adjuncts add complexity to the recipe and process. These are things you don’t want to deal with on your first batch, so keep it easy.

3. Brewing with unfiltered, chlorine-containing tap water. If you are on a municipal water supply odds are that it contains either chlorine or chloramines. To remove them you can either charcoal filter (I use a Camco 40631) or treat your water with metabisulfite, or alternatively use bottled water. One of the most common off-flavors I taste at homebrew club meetings is medicinal chlorophenol, which is formed by the combination of chlorine in the water or sanitizer and phenols from malt and yeast.

4. Squeezing the grain bag after steeping. This releases tannins, which give the body a rough texture. Steep your grains in a small amount of water (no more than three quarts per pound) and then rinse them by either pouring hot water over the grain bag or dipping the grain bag into a second pot of hot water. Edit: I've had a couple people dispute squeezing being an issue in the comments. I've tasted some tannin-y beer from new homebrewers, but maybe it was just from a high water to grain steeping ratio. I'll have to squeeze the grain bag into a glass and have a taste the next time I brew an extract beer.

5. Using liquid yeast. "Pitchable" liquid yeast cultures barely have enough cells to ferment a standard gravity beer on the day they are packaged, and their cells die quickly from there. A high quality 11.5 g package of dried yeast starts with as much as twice the cells as a fresh package of yeast from either Wyeast or White Labs, and retains high cell viability for much longer. While Fermentis, for example, claims a minimum of 6 billion cells per gram at packaging, the actual number tends to be much higher. Liquid yeast can produce great beers, but require a starter unless you are getting extremely fresh yeast and brewing a low-alcohol beer.

6. Not aerating the wort adequately. It takes several minutes of shaking for the chilled wort to absorb the ideal amount of oxygen to allow the yeast to complete a healthy growth phase. The healthier your yeast cells are the cleaner and quicker they will complete the fermentation.

7. Pitching when the side of the pot or fermentor feels “cool enough.” Use a sanitized thermometer to check the actual temperature of the wort before you add the yeast. Pitching when the wort is above 100 F is rare, but will kill the yeast. Ideally the temperature should be at or below your target fermentation temperature to allow the temperature to rise as the yeast grows and ferments. You can pre-chill the sanitized water you use to top-off after the boil to help bring the temperature down.

8. Fermenting at too high of a temperature. Take note of the ambient temperature of the room the beer is fermenting in, but realize that at the peak of fermentation the yeast can raise the temperature of the beer by as much as 7 F. Fermenting too warm can cause the yeast to produce higher alcohols and excessive fruity flavors. Letting the ambient temperature rise towards the high end of the yeast's range as fermentation slows helps to ensure a clean well attenuated beer, but for most strains is unnecessary. If you are unable to control the fermentation temperature, then choose a yeast strain that fits the conditions.

9. Racking to secondary. I know the instructions included in most kits call for transferring the beer from the primary fermentor to a secondary before bottling, but all this step accomplishes is introducing more risk of oxidation and wild yeast contamination. There is no risk of off flavors from autolysis (yeast death) at the homebrew scale in less than a month. At a commercial level the pressure and heat exerted on the yeast can cause problems quickly, but those conditions do not exist in a carboy or bucket.

10. Relying on bubbles in the airlock to judge when fermentation is complete. Wait until fermentation has appeared finished for a couple of days before pulling a sample of wort to test the final gravity. There is no rush to bottle, and doing so before the final gravity is reached results in extra carbonation. Once fermentation is complete and the beer tastes good, you can move the fermentor somewhere cool to encourage the yeast to settle out for clearer beer in the bottle.

11. Adding the entire five ounce package of priming sugar. In almost all cases this amount of sugar will over-carbonate the beer. Even for five gallons of beer this will produce too much carbonation for most styles and most brewers will end up with less than five gallons in the bottling bucket. Instead use a priming sugar calculator to tailor the weight of sugar you add to the actual volume of beer, the style of beer you are brewing, and the fermentation temperature.

Hopefully this list is able to help a few new homebrewers avoid some of the biggest pitfalls on their first batch. If any of the more experienced brewers out there has any lessons learned that are not included on the list please post a comment. You should also pick up a good basic homebrewing book, like John Palmer’s How to Brew or Randy Mosher's Mastering Homebrew, especially if you want to learn more of the “why” behind some of my suggestions.

There are many other things I would suggest as best practices, but they tend to be more style specific and are not worth worrying about on your first batch. I also think fresh high quality ingredients are a big key to making good beer, but most people brewing their first batch are buying and using fresh malt, yeast, and hops.


More Loophole than Law: The Food Additives Testing and Approval Process

Although consumers likely presume that a federal agency ensures the safety of ingredients in the food supply, in reality, this isn’t the case. For more information, view the infographic.

First, many additives have not been thoroughly tested. And the vast majority of safety testing of food additives is done by food manufacturers (or by people hired by manufacturers), not the government or independent laboratories. Second, because of a loophole in the law, companies can declare on their own that an additive is "Generally Recognized As Safe" (GRAS), and start adding it to food without even informing the government. Such ingredients are required to be listed on labels although in some cases they appear simply as "artificial flavorings." The infographic shows the convoluted process that the food industry follows.

Some additives do undergo a more formal government approval process, but even that is no guarantee of safety. There are approved additives that have been shown in subsequent independent studies to harm health, and are in the "Avoid" category in Chemical Cuisine. But the FDA rarely reviews the safety of additives (including GRAS substances) once they enter the food supply.


Lactic Acid Fermentation in Sourdough

A few years ago, I was asked to explain lactic acid fermentation in sourdough, and the difference between homo- and heterofermentation. Not an easy task, partly because I wasn't satisfied that I knew enough, or that I could reconcile what I was reading in bread-baking books with what I had learned in school. To sort it out, I had to dig deeper into the scientific literature. Answers are there in bits and pieces, although not in a context that is easy to make sense of. As I plugged away at deciphering current microbiology textbooks and scientific research, I started to see things in a new light. And so now, I want to share what I've learned with those who wish to know more.

First, I'd like to introduce the concept of a metabolic pathway. On paper, a metabolic pathway can be illustrated in a flow diagram that represents a sequence of enzyme-controlled chemical transformations. While the pathways in this discussion start with sugar and finish as various end-products, there are several intermediate compounds formed along the way as one thing is converted to the next. The names may be intimidating at first glance, but don't let them scare you. Knowing their chemical reactions and what all the compounds are is not as important here as understanding their overall purpose, which is to produce energy for the organism. Like all living things, microbes need energy to perform the tasks that enable them to live, grow and multiply.

Some pathways generate more energy than others. Through respiration, glucose and oxygen are turned into carbon dioxide and water via the Krebs cycle, also known as the tricarboxylic acid or TCA cycle. You may have seen it before if you've studied biology, because it's the same pathway we humans use. It is aerobic, meaning that oxygen (O2) is involved, and it generates far more energy than any fermentation pathway. Whenever oxygen is available, respiration is favored by facultative anaerobes like yeasts, because they will always take the path that generates the most energy under the prevailing conditions. For the most part though, bread dough is anaerobic (without oxygen), and fermentation is an alternative pathway that doesn't require oxygen. When yeasts ferment sugars, they produce alcohol (ethanol) in addition to carbon dioxide. Fermentation produces much less energy than respiration, but it allows microorganisms to carry on when no oxygen is available, or they lack the ability to respire as is the case with lactobacilli.

Bacterial fermentation is more varied than fermentation by yeast. Bacteria produce organic acids that contribute, for good and bad, to the quality of bread. Controlling acid balance and degree of sourness is something that artisan bakers strive to do, so it may be useful to understand where the acids come from and how their production can be influenced by things that are within the baker's control. In yeasted breads, acids come in small doses from naturally occurring bacteria present in flour and commercial yeast. (Fresh yeast generally has more bacterial inhabitants than dried, and whole grain flours more than refined.) In sourdough breads, acid-producing bacteria are supplied in much greater numbers from starter. There are many different species and strains of bacteria found in various types of starters, and because they produce lactic acid while fermenting sugar, they fall under the heading of Lactic Acid Bacteria (LAB).

Lactic acid bacteria common to sourdoughs include members of Leuconostoc, Pediococcus, Weissella and other genera. But by far, the most prevalent species belong to the very large and diverse genus, Lactobacillus. Based upon how they ferment sugars, lactic acid bacteria can be sorted into three categories. Please bear with me now, because while these terms may look impossibly long and technical, they are actually self-descriptive. Take homofermentative LAB for example. Homo-, meaning "all the same," refers to the end product of fermentation (by lactic acid bacteria), which is only, or "all" lactic acid. Heterofermentative then, means "different" or mixed end products. As lactic acid bacteria, heterofermentative LAB produce lactic acid, but they also produce carbon dioxide gas, alcohol or acetic acid as well.

SUGAR STRUCTURE

As carbo-hydrates, sugars are made up of carbon (C) and water, which is composed of hydrogen (H) and oxygen (O). The hydrogen and oxygen atoms are arranged in various configurations around a chain of carbon atoms which form the structural backbone of the molecule. The carbon chain may be various lengths, but sugars common in bread fermentations are of the 5- and 6-carbon types, referred to generically as pentoses and hexoses, respectively. Glucose and fructose are examples of hexoses. Pentoses are sugars such as arabinose and xylose.


Glucose Fructose Arabinose Xylose

Pentoses and hexoses can exist in the chain form, or in a ring structure which forms when dissolved in water. Single sugars, or monosaccharides, are often linked together into larger carbohydrates of two or more units. Disaccharides, containing two sugars, are important in bread fermentations. Maltose, which is made up of two glucose molecules, is the free-form sugar most abundant in dough. Sucrose, another disaccharide consists of one glucose and one fructose.

Glucose Maltose

Fructose Sucrose

-Sugars illustrated by Antonio Zamora. For a more complete explanation, with diagrams of starches and pentosans, please see his lesson, "Carbohydrates - Chemical Structure" at: http://www.scientificpsychic.com/fitness/carbohydrates.html

Sugars that can be fermented, and their end-products are variable from one species of LAB to the next. But the key lies in the structure of the sugar---particularly, the number of carbon atoms in the backbone of the molecule. Homofermentative LAB can only ferment 6-carbon sugars. In the homofermentative pathway, a hexose is processed and split into two identical 3-carbon pieces, which are passed down through the reaction sequence and transformed into lactic acid molecules. In contrast, heterolactic fermentation is based on 5-carbon sugars. Pentoses may be used directly, although more often, a hexose is cut down by removing one of its carbons. The extra carbon is cast off in the form of carbon dioxide gas, and the remaining 5-carbon molecule is split unequally into 3- and 2-carbon units. The 3-carbon piece is turned into lactic acid, while the 2-carbon piece will become either ethanol or acetic acid. Up to this point, heterolactic fermentation doesn't produce as much energy as homolactic, but it does give an advantage over homofermentative LAB, which cannot utilize pentose sugars.

Additional energy can be produced by turning the 2-carbon piece into acetic acid, but it requires the assistance of another substance. The term for this is co-metabolism, meaning that two substrates are used simultaneously---a hexose for its carbon backbone, and a co-substrate to facilitate the formation of acetic acid and generation of additional energy. The co-substrate can be one of a number of things including oxygen, citrate, malate, short chain aldehydes, oxidized glutathione, fructose and 5-carbon sugars. In the absence of co-substrates, the 2-carbon piece is turned to ethanol instead. Alternatively, when pentose sugars are fermented (used as the carbon source), acetic acid may be produced without the help of co-substrates.

Some lactobacilli can use oxygen as a co-substrate. Some cannot, and are inhibited by aerobic conditions. In any case, there is a small amount of oxygen in dough only at the beginning of fermentation, and generally not enough to affect acetic acid production to any extent. Likewise, citrate and malate aren't naturally present in significant amounts, and pentose utilization varies by species and strain as well as availability. While all these things may be used to the extent that they are present, it turns out that fructose is generally the one most available in bread dough.

All of the pathways in this discussion are glycolytic pathways. Glycolysis is the conversion of glucose to pyruvate, which is the springboard to both respiration and alcohol fermentation in yeast, to lactic acid fermentation in LAB, and to many biosynthetic pathways (manufacture of compounds used in other life processes). Oxygen is not required, so glycolysis is especially important to microorganisms that ferment sugars, like the yeast and bacteria which grow in the anaerobic environment of sourdough.

Homofermentative lactobacilli share the same glycolytic pathway with yeasts---the Embden-Meyerhof-Parnas, or EMP pathway. But in contrast to alcohol fermentation, pyruvate is reduced to lactic acid. In either of the two pathways here, the sugars are split into smaller molecules---two identical 3-carbon units (glyceraldehyde-3-phosphate) in the EMP pathway, or a 3- and a 2-carbon unit in the heterofermentative pathway. The 3-carbon pieces all follow the same path to become pyruvate and then lactic acid, while the 2-carbon acetyl-phosphate on the other side of the heterofermentative pathway can become either ethanol or acetic acid.

Glucose is not the only sugar that can be utilized. With appropriate enzyme systems, other sugars can be converted into glucose or one of the intermediates in the pathway such as glucose-6-phosphate (or in the case of pentose sugars, ribulose-5-phosphate). The ability to use other sugars varies by species and strain. Most sourdough lactic acid bacteria ferment glucose preferentially, but Lactobacillus sanfranciscensis separates maltose into a glucose-1-phosphate and a glucose. The glucose-1-phosphate portion is converted to glucose-6-phosphate to enter the heterofermentative pathway, and glucose is excreted from the cell.

In addition to obligately hetero- and homofermentive, there is a third type of lactobacilli characterized as facultatively heterofermentive. These are lactobacilli that are not restricted to one pathway or the other, but can use both. Facultative heterofermenters switch back and forth between the homo- and heterofermentative pathways depending upon which sugars are available. In general, they ferment hexoses via the homofermentive route, and pentoses heterofermentively. Most will use the hexose sugars first, although some strains ferment pentoses preferentially. Many co-metabolize fructose with maltose through the heterofermentative pathway, but use the homofermentative pathway when only maltose is available.

To put all this technical information to practical use, we need to consider factors that influence LAB activity and pathway selection. The end products are determined by the species and available sugars, which for lean doughs, depend upon the flour and the activity of enzymes. Whole grain and high extraction flours can affect acidification in two ways. First, the higher mineral (ash) content serves as a natural buffer system, which allows bacteria to produce more acid before the pH drops low enough to slow their growth. And second, grains supply pentose sugars in the form of pentosans. Although rye flours are best-known for these, pentosans are also present in wheat and other grains. (But, because they occur in the outer layers of the kernel, they are largely removed along with enzymes and many other substances in the milling of refined flours.) Cereal enzymes act on pentosans to some degree, freeing pentose sugars like xylose and arabinose that heterofermenters may be able to use according to species and strain. Pentoses will increase acetic acid production if they can be fermented or co-metabolized, either one.

Acidification is also influenced by hydration and temperature. Contrary to popular belief, all three groups of sourdough lactobacilli prefer wetter doughs a bit on the warm side, many growing fastest at about 90ºF or a little higher. For the homofermentive species producing only lactic acid, increasing activity by raising the hydration and/or temperature will increase acid production. Decreasing activity by reducing hydration or by retarding will slow production. There is a direct relationship between activity and lactic acid. During heterofermentation, for each molecule of glucose consumed, one lactic acid is produced, along with one carbon dioxide (if a hexose is fermented), and either one ethanol or one acetic acid. But under wetter, warmer conditions, where sugars are metabolized more rapidly, the tendency is toward lactic acid and alcohol production in obligate heterofermenters, and all lactic acid (homofermentation) in the facultative heterofermenters. Lactic acid production is directly related to activity during heterofermentation just as in homofermentation, even if only half the rate.

At lower hydrations and temperatures (lower activity), more acetic acid is produced, but not because of temperature per se. Acetic acid production is influenced indirectly by temperature, in that it affects the kinds of sugars available. The fructose that drives acetic acid production, is liberated from fructose-containing substances in flour, largely through the enzyme activity of yeast. And, because lower temperatures are more suited to yeast growth than higher, more fructose is made available to the bacteria at lower temperatures. At the same time, the bacteria are growing and using maltose more slowly, so the demand for co-substrates goes down as the fructose supply goes up. The ratio of acetic acid to ethanol and lactic acid goes up, because a higher percentage of the maltose is being co-metabolized with fructose. Reducing hydration has a similar effect of slowing the bacteria more than yeast, which I believe is the real basis for increased acetic acid production in lean breads made with refined flours.

Contrary to myth, the species that grow in sourdough starters are not tied to geographic location, but rather to the traditional practices in the different regions. Several organisms go into the mix, but the environment created inside the starter from the combination of flour, temperature and maintenance routines is what determines which ones will thrive. In type I, or traditional sourdoughs (i.e., those maintained by continuous refreshment at room temperature), the obligately heterofermentive Lactobacillus sanfranciscensis is the species most frequently and consistently found---not just in San Francisco where it was first discovered, but all around the world. And so it deserves special attention.

Lactobacillus sanfranciscensis is fairly unique among the obligately heterofermentive lactobacilli, in that it ferments no pentose sugars. And unusual among lactic acid bacteria in general, because it prefers maltose over glucose. But it will co-metabolize fructose with maltose to produce acetic acid. L. sanfranciscensis converts maltose into one glucose-6-phosphate which enters the heterofermentative pathway, and a glucose which is excreted back into its surroundings. This is a good arrangement for common sourdough yeasts, since maltose is the most abundant sugar in wheat doughs, and some lack the ability to break it down for themselves. Yeasts and other bacteria that can ferment maltose, generally prefer glucose. And so by providing glucose to competing organisms, L. sanfranciscensis actually helps to conserve the maltose for itself---just one of the ways in which it gets along well with other sourdough microorganisms, and perhaps one of the reasons it is found so often.

Alternate pathways are a recurring theme in the microbial world, because microorganisms have less ability to control their environment or to leave when conditions become difficult. They sometimes have to switch gears to survive. In that effort, lactic acid bacteria will utilize whichever fermentation pathway that generates the most energy within their capabilities and resources. In order of preference, the hierarchy seems to be heterofermentation with co-substrates (forming lactic acid and acetic acid), followed by homofermentation (all lactic acid) and heterofermentation without co-substrates (lactic acid and ethanol).

While traditional sourdough starters usually support one or more strains of Lactobacillus sanfranciscensis, it is often found in combination with the facultatively heterofermentive Lactobacillus plantarum, many strains of which can either ferment or co-metabolize at least one pentose sugar. Various other obligate and facultatively heterolactic acid bacteria are also common (obligately homofermentive LAB are only transient in the startup process and do not persist in established type I starters). Sourdough starters are sensitive ecosystems with complex associations of lactic acid bacteria, and combinations can be highly variable from one starter to the next. Lactic acid fermentation is as complex and varied as the organisms involved, and so sourdough processes may need to be optimized on a starter by starter basis.
- Debra Wink

Bibliography

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De Vuyst, Luc and Marc Vancanneyt. 2007. Biodiversity and identification of sourdough lactic acid bacteria. Food Microbiology 24:120-127.

Doyle, Michael P., Larry R. Beuchat, and Thomas J. Montville. 2001. Microbial physiology and metabolism, p. 19-22 Lactose metabolism, p. 653-655. Food Microbiology Fundamentals and Frontiers, 2 nd ed. American Society for Microbiology Press, Washington, DC.

Gänzle, Michael G., Michaela Ehmann, and Walter P. Hammes. 1998. Modeling of growth of Lactobacillus sanfranciscensis and Candida milleri in response to process parameters of sourdough fermentation. Applied and Environmental Microbiology 64:2616-2623.

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Katina, Kati. 2005. Sourdough: a tool for the improved flavour, texture and shelf-life of wheat bread. VTT Technical Research Centre of Finland.

Ng, Henry. 1972. Factors affecting organic acid production by sourdough (San Francisco) bacteria. Applied Microbiology 23:1153-1159.

Paramithiotis, Spiros, Aggeliki Sofou, Effie Tsakalidou, and George Kalantzopoulos. 2007. Flour carbohydrate catabolism and metabolite production by sourdough lactic acid bacteria. World J Microbiol Biotechnol 23:1417-1423.

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This article was first published in Bread Lines, a publication of The Bread Bakers Guild of America. Vol. 15, Issue 4, Dec. 2007.