Sunday, June 10, 2012

Balsamic Vinegar...Aged to Perfection


            While I was researching the chemistry of gelato, I kept coming up empty.  It was then that I realized that eating gelato is much more fun than researching it, so I decided to change my topic for this week to my other favorite thing here in Italy: balsamic vinegar.  After obsessing over how great the balsamic vinegar at dinner was earlier this week, I realized that I had absolutely no idea how balsamic vinegar is made. So, decided that I should find out to see if I could make it at home.
            It turns out that even though balsamic vinegar is classified as one, it isn’t really a wine vinegar at all because it does not come directly from wine.  Instead, balsamic vinegar is made from white grape pressings (typically of the Trebbiano variety), that are first boiled down to a dark syrup.  Even though white grapes are used to produce traditional balsamic vinegar, the end product has a dark color due to the deactivation of proteins in the grape musk when they are boiled down.  This dark syrup is then fermented in anaerobic then aerobic steps involving yeasts. 
Once the syrup has fermented, the ethanol that has been produced is converted to acetic acid by ambient acetic acid bacteria.  When this process is complete, the aging process involving a series of wooden barrels and at least 12 years begins.

Conversion of Ethanol to Acetic Acid

            Aging in barrels made of different types of wood is an extremely important component of making tradition balsamic vinegar.  A barrel set of five barrels, each smaller than the next and made of a different woods than the preceding barrel, is used to age the balsamic vinegar and imbue it with different properties.   In addition to giving balsamic vinegar a robust taste profile, the wooden barrels allow water to escape and for the vinegar to concentrate.  The wood also allows for the acetic acid and other volatile compounds to remain intact while still exchanging small molecules with the outside environment by acting as a semi-permeable filter (just as in wine production).

The Barrel Set Used for Aging Balsamic Vinegar

            The balsamic vinegar in the casks is never removed all at once; instead, small portions of it are removed from the smallest cask each year, and are replaced with a portion from the preceding cask.  The contents of the largest cask are replaced with the newly boiled down and fermented syrup.  This process is important for making sure the vinegar content of each cask remains the same, and to compensate for loss of volume due to bottling, leakage, and evaporation of water.  The balsamic vinegar must stay in these casks for at least 12 years to be considered traditional balsamic vinegar.
            The end composition of balsamic vinegar is extremely complex, and involves a multitude of different polyphenolic compounds (these compounds often act as antioxidants); acids such as acetic, malic, and gluconic acid; and different sugars like glucose and fructose.  Some of these compounds have purported health benefits, and many people (including my Grandmother’s 105 year old friend) often take small doses of vinegar every day to promote good health.  Regardless of any extra benefits, balsamic vinegar makes for an incredible way to add a ton flavor to many dishes without using very much (although I’ll be honest, I often just pour a ton of the stuff on to bread, or really anything because it tastes so good).
            Overall, balsamic vinegar is the classiest of all the vinegars due to its extensive aging process (12 years compared to the normal few months for other vinegars) and its long history that began ~900 years ago in Modena, Italy.  It’s uses range from providing health benefits to providing amazing pops of taste to a variety of dishes and appetizers. Despite all this, my most important discovery during this endeavor to find how to make balsamic vinegar is made is that if I were to try to make this tasty substance at my house, I would probably end up making something inedible.  I figure I’ll just leave it to the professionals and buy a nice bottle of aceto balsamico here in Italy to take home with me; in the end, it just seems like a better idea.

Bottled Balsamic Vinegar



http://www.whisky.de/archiv/experts/starch.htm

http://purehealthyoil.com/recipe/balsamic-vinegar-is-not-a-wine-vinegar/

http://en.wikipedia.org/wiki/Vinegar

http://en.wikipedia.org/wiki/Traditional_Balsamic_Vinegar

http://voices.yahoo.com/10-health-benefits-vinegar-561289.html

http://www.amazon.com/Italian-Products-Traditional-Balsamic-3-5-Ounce/dp/B001D6B1BC

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