Mas Vinor Por Favor

April 11, 2011

Torah Kachur

Torah on Location in Mendoza, Argentina


There are two things I can't live without: oxygen and wine.  So it seems perfect that I find myself in Argentina with lots and lots of wine and I believe there is some oxygen around too. 


Wine is made from fermenting grapes using the natural yeasts that grow on the vines and, to point out the obvious, is incredibly delicious.  It is both the quality and type of grape and also the type of yeast that determine the difference between the wines that end up in a box or those that end up in a bottle.  Many wineries are often ultrasecretive socieities protecting their magical potions and they can supplement their grape mixture with a particular blend of yeast that they prefer for the fermentation process.  When the grapes are crushed (a la Lucy) the sugars in the juices are released and can feed the yeast so the yeast can grow.


The types of yeast that grow on the grapes are the Saccharomyces variety - the same one that you've got in your cupboard for making bread.  But winemaking not just as easy as grapes, yeast and a fermentation chamber, as anyone victim to any homemade wine can attest.  There are many different varieties of both grapes and yeasts that yield different types of wines.  Yeast strains like S. bayanus, S. oviformis, S. logo and S. oxydans are just some of the different genetic strains used for fermentation.  It is the variety and mixture of the types of yeast that grow in different areas of the world that leads to some of differences in wine types.


Fermentation is when the yeast produce that wonderful essential ingredient in wine - alcohol. The yeast use sugar as food and undergo a process to slowly use the energy stored in sugar in a process called glycolysis and then and produce ethanol as waste.  Carbon dioxide is also produced as waste and provides the bubbly in bubbly.


Ethanolic fermentation wine beer production science in seconds


The nectar of the gods has a normal alcohol content of 11-12% which allows for moderate consumption and inebriation (yeah right) because the yeast die at their own hand.  As the byproduct of yeast metabolism builds up, the ethanol actually kills the yeast thus limiting the entire process.  Any beer or wine to claim higher alcohol content has been fortified with more ethanol, much to the chagrin of your impending hangover.

And just in case you can't really get enough - study the science and art of wine making at the University of Auckland.



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