Marcy Goldman edits the site www.betterbaking.com

Articles on Baking
 

A YEASTY YARN: Profiles in Leavening

Nothing says lovin' like...fresh bread. And nothing intimidates quite as much. But these days, with heavy duty mixers out there, as well as bread machines (NOT for baking - for dough kneading only) there is no excuse for store bought bread. Easy, high rising loaves are a snap. But it helps to know a bit about the many yeasts out there. In this column, we introduce you to some basics about yeast. We have also given three classic straight dough recipes (as opposed to sourdough or longer rising breads) to practice with.

KNOW YOUR YEAST: A BAKER'S BEST FRIEND

The more you know about yeast, the more you can appreciate the joys of working with it. Many bakers are unconditionally loyal to a particular format or brand. In professional circles, consistency is very important so yeast is chosen carefully. At home, you need a yeast, much like your best friend, which you can count on for most of your baking needs. But where to start? Here is a survey of the yeast that is out there.

Fresh Yeast
Your grandmother probably used fresh yeast. Purists adore it. Doughs made with it are supple and bouncy and the yeast fragrance is subtle. Fresh yeast, usually the choice of professional bakeries, is best for dough which will not undergo excessive handling. The strains used to make fresh yeast are different from those used to make dry yeast.

Fresh yeast, which can be a joy to use (and elusive to find) and a mystery, does have its drawbacks. It is far less stable a product than dry. Fresh yeast in compressed form or in "cream" form is delivered every other day to the commercial baker - sometimes by the tanker truckload!
 

Active Dry Yeast
Most cookbooks still call for "active dry yeast". Bakers who have honed their skills with this yeast, know what to expect from it, and that’s a plus. "Active dry" is being replaced by "instant yeast". When "active dry" is called for, you may substitute "instant" if you like (see the substitution guide). As with fresh yeast, active dry is a live culture. Under most circumstances, it must be proofed or reconstituted with water and a bit of sugar before use. Once it is exposed to air and moisture, it starts to lose its potency. A container of active dry yeast should be well sealed and refrigerated or frozen. Always take note of the expiration date.

Dry strains are selected for their stability under stress (drying, re-hydrating, handling). Dry yeast contains 5% to 8% moisture compared to 70% to 72% in fresh. After re-hydration (adding water to proof) or mixing with other ingredients, there is a "lag phase" which the dry yeast requires in order to become active again. Fresh yeast, of course, has no lag phase.


Instant Yeast
a.k.a. "Fast Rising" or "Bread Machine Yeast"

This yeast comes in a few forms and has many different names (depending on the company and its packaging). I cannot recommend instant yeast enough for home bakers. Instant yeast is very active and very tolerant. It offers the baker a wide margin for error or experimentation. It activates rapidly in warm water and can be added to other ingredients in its dry state - so feel free to add it to the water in the recipe or the flour. Too much flour, water, salt, sugar, or fat...can destroy other yeasts but this one is up to the errors most home bakers can perpetrate¾as they are learning). It's a good keeper, too: 3 to 4 months in the freezer. Instant yeast is a good choice for rich coffee cakes and sweet breads which you may wish to freeze and for doughs which will see a slow rise in the refrigerator. If you use a lot, buy the small can of this yeast. If you use it daily, buy the vacuum bricks of it. Store unused yeast in the freezer. The sachets or packets do not really match the amounts called for in today's recipes, especially bread machine recipes so I do not encourage you to buy them.

Instant yeast's qualities become liabilities when you use too much of it. How do you know if this is the case? A premature rise and an overt yeasty, "beery" odor. Problems also arise when you allow dough to proof too long. Make sure you do not allow dough to rise beyond double their original size - 60% to 70% is fine. You can always opt for more fermentation in the final rise. Over-fermented dough reduces the shelf life of the final product. The solution is very simple: less is more. Decrease the yeast portion by 15% to 25% increments. You can use too little yeast, but you won't compromise taste and structure if you let it rise slowly. This may not work, however, with rich or heavy breads (i.e. rye) which need good fermentation power and mixtures which contain perishables. No two bakers, or kitchens, or ovens, are alike, so don't be afraid to do some tweaking.

Substitution guide: 1 tablespoon active dry = 2 1/2 teaspoons instant = 3/4 ounce fresh.

I recommend Fleischmann's Instant or Bread Machine Yeast.