I want to sing praises to an unsung microbial hero of humanity. The humble yeast. The unseen and its unwavering willingness to change the chemistry and flavor and consistency of our food. I recently rediscovered this microbe while making a sourdough starter and this process inspired this review of the most elementary and essential fungus to a human's life.
This member of the fungus kingdom is a unicellular micro organism that consumes plant sugars and excretes CO2 and alcohol. Although there are more than a thousand varieties of recognized yeast, one species, Saccharomyces Cerevisiae has become industrialized and used in the production of bread and beer. Furthermore, yeast has been used by humans in processes to improve and preserve food for thousands of years and a hallmark of the agricultural revolution that required the improvement and preservation of food. Yeast is used to leaven bread, brew beer, ferment pickles. It is used in the processing of an extraordinary amount of foods that societies have come to rely on and enjoy.
Wild Yeast vs Commercial Yeast
Many recipes may call for commercial yeast, which is reliable and can be counted on to be mixed into any recipe and start doing its work, consuming sugars and producing waste, creating that fluffy and airy texture in bread or a fail safe way for breweries to jump start and expediate their brewing processes. Commercial yeast is a reliable partner. Then there is wild yeast, which is borderline magical.
Wild yeast is like catching air in a bottle. When cultivating yeast, you pretty much prepare the potential inhabitants food, water and shelter and they arrive by their own motives. The part that I find most fascinating of all is that different yeast will take up residence in your starter depending on geography and time. To think about a bakery that has maintained its "levain" yeast mixture for more than 100 hundred years. This means that communities of this particular microbe can survive indefinitely and maintain a particular flavor and rise profile based on the microbes in the air at the start of that starter's existence. Which also leads to the nostalgic idea that when you start your own starter, capturing the wild yeast in its new home, you are capturing an essence of that time and place, preserved indefinitely in a jar of flour (unbleached) and spring water.
This concept holds true for breweries and distilleries that want to develop a unique taste and stand out from the rest. Never underestimate the power of yeast to transform a beverage into an experience and a memory. When I had my home distillery, I mainly used commercial yeast to get my brews bubbling, however I am wondering how my brews would have turned out had a taken the chance to cultivate some local Be'er Sheva microbes into the brews, I am sure they found their way in by any means.
Pickling and preserving is another aspect to this story. The act of canning, pickling and preserving has both improved food and has proven essential to survival during desperate times. The complex biological and chemical processes that are occurring can be boiled down to lactobacillus bacteria that reproduce in the pickling jar in the presence of salt. The salt slows competitive bacteria allowing the "good" bacteria to thrive. You can always tell when your pickling is coming along nicely when you start to see bubbles forming in the brine of the pickling jar. Pickling let's you enjoy your own produce far into the fall and winter months and adds great taste and good probiotics to any meal.
When dealing with fermentation of bread, beer, or preserving food, things can go wrong and "bad" bacterial colonies can form and develop. Not to worry or be discouraged, try to be a little cleaner next time, but don't let it prevent you from there being a next time! The best feelings of success come with the error side in trial and error. Also, those microbes are present, invite them in and talk to them, maybe they can't hear but I am sure they can sense your good will and invitation. Above all, be observant, these are small creatures and the smallest of changes are probably significant!
When one stops to think about yeast, how important it is to our diet, how prevalent it is in our environment, how unseen of a microbe and how much presence it holds in society, gives reason for appreciation that this tiny creature holds the weight of humanity on its shoulders.