Microscopic yeast are in the air all around us. They are the reason that we have beer, wine, and other alcoholic drinks.
Beer (and therefore yeast) lubricated the rise of civilization:
At some point in prehistory yeast fell into the gruel of one of our ancestors–after all, yeast is in the air around us. The gruel had been made from grain that had started to sprout (when seeds sprout an enzyme is released that breaks the starches stored in the seed into sugars the seedling will need for energy). Or perhaps the gruel tasted bad and our ancestor spit into the bowl (our saliva contains enzymes that break starch into sugars). The yeast started eating the available sugars. As they ate they produced ethanol (C2H5OH) and carbon dioxide (CO2). The next day, our ancestor would have noticed some froth on the top of the gruel, sipped it, and she (yes, she) found it didn’t cause problems. In fact, she felt better after drinking the frothy liquid.
She had discovered what Oscar Wilde discovered generations later:
“I have made an important discovery…that alcohol, taken in sufficient quantities, produces all the effects of intoxication.” — Oscar Wilde
Without yeast we would not have beer or civilization.
A couple of weeks ago my friend Ron (who runs Kelsey Creek Brewing) gave me a container of Irish ale yeast–a big container of yeast. So much yeast that I could have used it for 100 gallons of wort (rather than the 5 gallons I planned to make). I put the plastic container in the refrigerator for use in the following day’s brewing. Cold temperatures make yeast less active. But, even with the cold, they were active enough to produce a lot of CO2 gas.
The picture above shows the aftermath of my opening the plastic jar. I’m still finding yeast in places in our kitchen.
Fortunately for me, my wife loves the beer I make.
Here is some yeast (in a Better Bottle fermenter) eating sugars and producing CO2 and alcohol:
- How does yeast affect the taste of a beer? (52beers.wordpress.com)