I am a big fan of yeast. Yeast are my friends. They work hard for me. I like yeast so much I keep a few in a tub in the back of my refrigerator. There they happily coexist with their good friends the lactobacilli, all chomping away in froth of water and wheat flour.
Cats and dogs make me sneeze. I am unable to keep parakeets happy. But even if they are mere fungi, my yeast make great pets. I just have to feed them once a week, or leave them with friends when I go on vacation.
In return for this modest attention, on Saturday mornings I can drop a few sticky spoonfuls of this fungus-bacteria culture into a mixture of water, wheat flour and salt and let it all sit for a few hours. The yeast will ingest the sugars of the flour and expel carbon dioxide, which is trapped in the elastic proteins of the wheat dough. When baked it makes beautiful, puffy, tender, filling bread. The yeast adds volume, the lactic acid from the friendly bacteria adds flavor. I can attest from personal experience that this and a little butter can make your family very happy. I read that this technique dates to the dawn of civilization. I have something in common with the ancient Egyptians — we put microbes to work. I think it borders on miraculous. Thanks, yeast.
That’s not all, of course. Long, long ago humans figured our how to keep a very useful and good yeast we now call Saccharomyces cerevisiae. In fruit juice or a mixture of water and grain the busy S. cerevisiae take in sugars and give off carbon dioxide and alcohol. We call it fermentation, and as Benjamin Franklin supposedly said of wine, this is a sign that God loves us and wants us to be happy.
I was pondering yeast recently when I came across a terrific article by John-Manuel Andriote in The Atlantic (“Yeast: Love and Fear, Death and Beer,”) that convincingly explained the whole microbial thing, all the fungi ups and downs. There’s more to it than bread, beer and wine. The genome of S. cerevisiae has been mapped and scientists found that inserting strands of useful DNA from another creature, human beings for one, the yeast will reproduce with the desired traits. It’s biotechnology, or genetic engineering, or whatever you want to call it, but it produces many valuable medicines and vaccines. Half the insulin used to keep diabetics alive is produced by modified yeast (the other half by modified bacteria), reports Andriote. He quotes the discoverer, Gerald R. Fink of MIT: “A lot of what people are having injected into them are vaccines that are human protein made in yeast by putting the gene from humans into yeast.” And Fink addresses the critics, who want warning labels on bags of sugar made from GMO beets, but don’t say much about the products of GMO yeast. “Why is it not OK to eat things, but it’s OK to inject them in your veins?”
An interesting point. I looked further when the opponents of Initiative 522 reported that winemakers or brewers can use genetically modified yeast to produce their product, which will then be exempt from labeling requirement, being alcoholic beverages. There is a GMO yeast for winemaking invented in part at the University of British Columbia, designed to ferment with fewer of the chemical byproducts that cause young red wine to give some people headaches. It’s called ML01, approved by the FDA for use in the United States. Apparently, it’s not used much and those who use it aren’t advertising it, and most wine is filtered so you won’t drink it anyway.
It does not cause me fear. It does, however, make me wonder about the possibilities. Yeast, I’m a fan.
Tracy Warner’s column appears Thursdays and Fridays. He can be reached at firstname.lastname@example.org or 665-1163.