My Kitchen Could Be a Yeast Farm
One of the many lightbulb moments for me in Michael Pollan's book The Omnivore's Dilemma came when the author harvested his own yeast to make bread. I'm always on the lookout for ways to replace items I currently pay for with free or cheaper versions of the same. But when I read about harvesting yeast, I pictured heading out to a stream in the woods, scraping fungus off wet rocks or something like that.
Turns out it's nothing so difficult. Yeast for making bread can be harvested from the air right in your kitchen or backyard.
People do it not just to save money but to develop unique bread that is a truly local cuisine. Pollan doesn't give very specific instructions for harvesting yeast from the air, but naturally, plenty of people on the Internet do.
According to this article, wild yeast is not exactly the same fungus as the dried yeast we buy in the grocery store, but it is pretty close. Every recipe I found for gathering and using wild yeast resulted in a sourdough starter -- that dish of doughy stuff credited with keeping settlers alive in the days of California's '49ers. It's not clear to me if it's possible to make bread that isn't sour with wild yeast -- but personally I don't care because I like sourdough better.
The nice thing about making your own starter is that, if it works, you only have to do it once. Here's an account of a woman who kept her starter going for 15 years. Now, I may only pay about $5 for a month's supply of yeast (I've been making my own bread in the machine several times a week), but extrapolated over a decade, I could save $500.
If you live in the Bay Area, your wild-harvested yeast may make a bread tasting very similar to sourdough you buy in the store. If you live somewhere else, you might end up with a different flavor. That is, if the yeast in homemade starters truly does come from the air; this site suggests that it really comes from yeast already present in the flour used.
As I look over various reports of experiments with sourdough, it's clear that this is a little science experiment; not a very difficult one, but one for someone more interested in the process than in tidy, speedy results. It's also an experiment that requires a little courage. I'm a food-poisoning-fearing girl, and the idea of setting out some bland, wet food product for days to encourage the growth of fungus and bacteria is a little unsettling. The experience of the top poster in this discussion did nothing to assuage my fears -- her starter turned green and pink! The going advice online is to discard any starter that starts smelling aggressively foul or non-foodlike. An alcoholic, beery smell, on the other hand, sounds quite normal.
Instructions for getting started:
This step-by-step from the Bay Area includes helpful photos for how your starter should look, and precise instructions for when to put some of the starter into the fridge to save for a future batch.
While many sites are quite general in their instructions, The Fresh Loaf offers precise measurements, which I plan to follow when I try my own starter. This site also offers a solution to a common problem -- many first-time yeast gatherers complain that their yeast seems to "die" after a few days, but according to The Fresh Loaf, it just needs a little cider to adjust the pH and get things growing again.
Not feeling so adventurous? There's another way to get yourself a starter that you can milk for decades and never have to buy yeast again -- buy or borrow some starter from a more experienced baker and fungus farmer. Here's a site that sells the stuff (note: I haven't vetted this company), and this site will even mail you some dried starter, derived from a historical strain, free of charge.
And by the way, once you have a good starter going, you can make the bread right in the bread machine.
This usenet posting contains lots and lots of information on managing starters old and new.
Books with instructions on making and maintainng a starter include:
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