In episode 41 of the Japan Distilled podcast, your hosts Christopher Pellegrini and Stephen Lyman roll up their sleeves and dive back into a very specific aspect of alcohol production: the absolute necessity of yeast.
CHRISTOPHER PELLEGRINI Vermont born and bred, long-time Tokyo resident and author of The Shochu Handbook, Christopher learned about delicious fermentations as a beer brewer at Otter Creek (Middlebury, VT). He now spends most of his waking hours convincing strangers that shochu and awamori are unlike anything they’ve ever tried before.
STEPHEN LYMAN discovered Japan’s indigenous spirits at an izakaya in New York City. He was so enthralled that he now lives in Japan and works in a tiny craft shochu distillery every autumn. His first book, The Complete Guide to Japanese Drinks, was nominated for a 2020 James Beard Award.
Stephen and Christopher have a deep and abiding respect for this single celled organism.
If you have any comments or questions about this episode, please reach out to Stephen or Christopher via Twitter. We would love to hear from you.
World’s Biggest Overachiever?
There may be no single cell organism more vital to human civilization. Archeologists have discovered ruins of ancient civilizations in which it was clear that they were working with yeast even if it wasn’t actually identified as a living organism until Louis Pasteur in the 1850s.
Yeast has been used to make bread and alcohol since time immemorial. While you can make unleavened bread without it, you simply cannot efficiently make ethanol without yeast.
The Science of Yeast
This single celled organism has two respiratory pathways. One for an oxygen rich (aerobic) environment and one for an oxygen poor (anaerobic) environment. When the aerobic respiratory pathway is activated, the yeast will convert oxygen and sugar into water and carbon dioxide (CO2). When the anaerobic pathway is activated, it will convert the sugar into CO2 and alcohol. Therefore, alcohol fermentations are almost always submerged in liquid to deprive the yeast of oxygen.
The Art of Yeast
Yeast’s primary job in alcohol production is to convert sugars to alcohol, but it also adds flavors and aromas both through by products it creates while alive, but also when its cells die their own enzymes digest their bodies into aroma and flavor compounds. Managing this delicate balance of flavor and aroma derived is one of the arts of alcohol production.
Types of Yeast
There are hundreds if not thousands of species in the world. Yet one, saccharomyces cerevisiae is dominant for both bread and alcohol production. While this particular species shares the same DNA, strains of s. cerevisiae used for bread and alcohol are different. In fact, the strains used for beer versus wine versus sake versus spirits are different as well. Bread yeast is more resistant to the adverse conditions present in an oven while alcohol yeasts remain active at higher alcohol concentrations. And of course, those used for wine can remain active in high alcohol concentrations than those used for beer.
Of course, each yeast has its own flavor and aroma characteristic as well. Many have been cultivated specifically to express green apple or star anise or banana notes. As a result, yeast may very well have a larger impact on the final product than any other component other than the main ingredient and sometimes even that.
Much More to Explore
Of course, there is certainly much more to learn. Please have a listen and let us know what you think.