Dumb Yeast

Time to talk about yeast, because without them, I wouldn’t have much to write about. So, at the risk of scraping from the bottom of the barrel, here I go…

Bet you didn’t know that yeasts have a tendency to kill themselves in their own excrement. They’re such voracious consumers of sugar that they ignore how fast they expel ethyl alcohol, carbon dioxide and heat.

Yeasts can cook themselves to death, especially in a large tank, because the act of fermenting sugar gives off a wasteful smidgen of heat. While you wouldn’t be able to feel anything remotely warm from one yeast doing its work, put billions of them together and you’ve got a mini power plant.

They start dying off over 130 degrees, which is why those dimpled stainless-steel cooling jackets or internal coils are crucial to keeping large batches of micro-winemakers happy. We commonly set the thermostats to an optimal 85 degrees.

Most yeasts struggle to work once they are swimming in 14% alcohol or more. At 15%, all but the specially-bred über-yeasts are ready to explode.

And you don’t want them unhappy, because disgruntled individuals cut loose with nasty aromas and flavors that can sabotage a season’s worth of work in the vineyard.