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Rising to the occasion

(article, Matthew Amster-Burton)

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A reader writes:

"I have made your pizza-dough recipe a couple of times now, but I've used regular yeast instead of instant. Are there situations when one should always use one kind instead of the other? Or does it really matter?"


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In short: No, it doesn't really matter. And if you don't know which kind to buy, go for instant.

But why are there so many different kinds of yeast, anyway?

Like other live ingredients, such as oysters and lobster, yeast can be intimidating. Its performance is unpredictable: Is this batch fresh? Did you use more or less salt this time? What's the temperature today? All of these things affect rising time.

So the yeast industry keeps trying to make yeast easier to use. In doing so, the industry has also made yeast harder to understand, by giving the same product half a dozen different names.

In the beginning, there was sourdough. Sourdough yeasts are everywhere — in the air, in a bag of flour, in the frosty layer on the surface of grapes. In concert with friendly bacteria, these yeasts make wonderful bread, but you have to capture them and make a starter, and then you have to keep your starter happy with constant infusions of flour and water.

[%image reference-image float=left width=400 credit="Photo courtesy Matthew Amster-Burton" caption="Yeasty homemade dinner rolls."]

Making a starter isn't hard; Nancy Silverton's [%bookLink code=0679409076 "Breads from the La Brea Bakery" newpage=true] has a respected method, and Peter Reinhart's newpage=true has an even easier one. Jeffrey Steingarten describes making his starter in an essay reprinted in the new [%bookLink code=1598530054 "American Food Writing" newpage=true] anthology, edited by Molly O'Neill.

To build a sourdough starter, you mix some flour and water and wait for it to get bubbly and smelly, adding additional flour and water at prescribed times. A sourdough starter is needy — like a puppy, but not as cute. The advantages of sourdough are that the yeast is free and the products are delicious.

But baker's yeast, Saccharomyces cerevisiae, is faster and more reliable. Originally a byproduct of beer brewing, cakes of baker's yeast have been produced in factories since the late 1800s. You can still find fresh cake yeast in the dairy section of the supermarket, but it's no more durable today than it was in its heyday. Cake yeast consists of living, metabolizing cells, and those cells get hungry; you need to give them some dough to chew on within a week or two. Plus, cake yeast is expensive.

It does feel nice between your fingers, but I can't recommend it. Some professionals still use cake yeast because it's what they're used to. But Grand Central, the largest artisanal bakery in the Pacific Northwest, uses active dry yeast.

Active dry yeast dates from World War II, when the U.S. government funded research into durable yeast. The armed forces needed to be able to stockpile all the necessary ingredients to bake bread for U.S. troops abroad. Fresh cake yeast went bad in a matter of days. Stored properly, active dry lasts a year or more.

But active dry has two downsides. For most recipes, you have to proof it: dissolve it in warm water and make sure it's still fizzy and alive. This stops a lot of home bakers in their tracks. (Are you sure the water is 110 degrees?) Also, due to the drying process, active dry granules are coated with a layer of dead yeast cells. How active is that?

Enter instant yeast, also known as RapidRise, QuickRise, or Bread Machine yeast. These are all the same thing: finely granulated, 100 percent live yeast, sometimes dusted with vitamin C for better performance. (Yeast cells go crazy for vitamin C, like Linus Pauling.)

What's the difference between instant and active dry? Instant is more finely ground, so it dissolves quickly, and it undergoes a different drying process, so there are no dead cells. You can mix this yeast directly with the flour; you don't need to proof it beforehand.

Instant hit the market in the early 1980s. (I assumed that it came along with the bread machine, but actually the machine came later.) Instant yeast was supposed to draw new customers, the kind scared off by active dry's fiddly requirements. The yeast market, in the imagination of executives, would grow out of control like an over-leavened dough.

It didn't work; according to a Fleischmann's Yeast representative, instant did not make Americans crazy for yeast. The company wouldn't share sales figures for its yeasts, but the manager at my local supermarket said active dry is still his best seller. People continue to buy active dry because they're used to it and recipes call for it.

But you are smarter than the average consumer, so you should buy instant. Keep it in the freezer for up to a year or until the expiration date. When using instant in a recipe calling for active dry, skip the proofing step and add the yeast to the dry ingredients. Instant is somewhat more active than active dry, so you can reduce the amount of instant by a third. But nothing bad will happen if you just substitute an equal amount.

What about flavor? There's almost no difference. I've seen it argued that instant sacrifices taste because it works faster. But Cook's Illustrated,_ Jeffrey Steingarten, and Peter Reinhart — all of whom know a thing or two about flavor — use instant.

As for nutritional yeast, forget about it; the sour powder may be tasty on popcorn, but the yeast itself is dead.

What will the yeast barons come up with next? If they keep up with this relentless press toward convenience, soon you won't have to buy yeast at all. Supermarkets will sell fully baked bread, right there in the store. 

p(bio). [ "Matthew Amster-Burton"] writes about cooking and culture from his home in Seattle. He keeps a blog titled Roots and Grubs.

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