It’s undeniable – no matter what direction you look, yeast is everywhere! It floats freely in the air, reproducing, metabolizing and being the reason for the creation of (depending on the type of yeast) mold, mildew, wine and beer!
Being that this is a beer newsletter, I’ll concentrate on the latter. Since ancient times, mankind has known that yeast can make an alcoholic drink out of nearly any plant, fruit or vegetable. Some archeologists claim that primitive forms of yeast selection were put into use by brewers as early as 1400 B.C.
When viewed under a microscope, brewer’s yeast appears to be a chain of little fungus organisms. (Their life’s work is to convert sugar to both carbon dioxide and alcohol.) Yeast was first viewed under a microscope by Dutch scientist Anton van Leeuwenhoek, the inventor of that instrument. It is believed that beer yeast was the first thing Leeuwenhoek sought to observe under the lens!
By the mid 1800’s, it had been determined that malted barley was very receptive to yeast. And there were two primary strains of yeast that worked particularly well in the making of beer – one was successful in producing lagers, and the other was instrumental in creating ales.
Ale yeast gives beer its expressive, complex, fruit flavor. This yeast ferments at the top of the brew barrel in temperatures of 55 to 75 degrees F. In yeast past, this top-fermenting yeast lent itself to contamination as it worked in close proximity to the air where unwanted yeasts came into play.
Lager yeast is bottom-fermenting and works in a cooler environment of 32 to 55 degrees F. Lagers of today are stored for many weeks (even months) while the lager yeast works its magic, giving lagers their clean, soft taste.