How yeast works, a scientific study

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Zacharomyces

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In 1839 the Annals of Chemistry, Volume 29, by Friedrich Woehler and Justus von Liebig, stated:

"Beer yeast, when dispersed in water, breaks down into an infinite number of small spheres. If these spheres are transferred into an aqueous solution of sugar, they develop into small animals. They are endowed with a sort of suction trunk with which they gulp the sugar from the solution. Digestion is immediate and clearly recognizable because of the discharge of excrements. These animals evacuate ethyl alcohol from their bowels and carbon dioxide from their urinary organs. Thus one can observe how a specifically lighter fluid is extruded from the anus and rises vertically, whereas a stream of carbon dioxide is ejected at very short intervals from their enormously large genitals."


So now you know, and knowing is half the battle!
 
Most likely they were looking at chained yeast colonies, failing to realize that each cell was a complete alcohol factory. Yeast were first though of as animals, then plants, then fungi.
 
Glycolysis is the pathway that our blood sugars first enter to make usable energy. At the bottom of the pathway, we end in pyruvate. If no oxygen is available (like with yeast in an oxygen deficient wort), we shunt off to lactate (or lactic acid). This is why our muscles burn when we sprint for a while.

So why does this matter?.. Well, instead of lactic acid, yeast produce ethanol to keep glycolysis going.

In essence... if we could do the same thing, I'd go to the gym a hell of a lot more often!
 
Sorry for digging up this old thread.

But this weekend I read something that puts Liebig's text in perspective. Liebig was a strong proponent of a chemical explanation of fermentation and could not believe that the yeast has anything to do with it. His text was a satire intended to ridicule the theory that yeast is responsible for fermentation.

I thought that this was important for the understanding if this text.

Kai
 
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