Buying Yeast

Dry Yeast

For those of you who buy yeast in jars or in bulk, 2-1/4 teaspoons of dry yeast equals one packet, which usually weighs 1/4 ounce.

Fresh Yeast

For fresh, or compressed yeast, one 5/8-ounce cake equals one 1/4 ounce package of dry yeast (water adds the weight in the compressed yeast). And 1/3 of a 2-ounce cake of compressed yeast equals one package dry yeast.

Choosing the Right Yeast
There are a several different types of baker’s yeast. The following are three of the most popular choices among home bakers, including dry active yeast and fast-rising active dry yeast.

Active dry yeast

For the home baker, single-use packets of active dry yeast are often the best bet, although the yeast usually also available in bulk bags. Professional bakers usually use bulk baker’s yeast, or a bread starter. Active dry yeast is the most reliable and probably the most common type of yeast for the home baker. Store it in an airtight container in a cool, dry place. If left in the open, yeast is more susceptible to moisture and can become active, going bad before it is even used to make bread.

• Active dry yeast is highly perishable; always check the expiration date before use.
• Must be rehydrated before use
• Easily damaged by liquids above 115°F (46°C)
• Suitable for recipes that require more than one rise
• Suitable for cold-proofed doughs
• To use in place of instant yeast, activate according to package directions, using a portion of milk or water from the recipe rather than additional liquids.

Instant Dry Yeast

This type of yeast is relatively new on the market and boasts rising times that are half that of conventional dry active yeast. Thanks to its unique manufacturing process, instant yeast is guaranteed to be 100% active, so it's ready for use straight from the package, and its behavior is consistent over time. Due to its small grain size, instant yeast will readily dissolve in the ambient moisture of a dough, eliminating the need for rehydration. Experts suggest mixing this yeast with dry ingredients first, before adding the liquid. Given its stability and shelf life, instant yeast is safe to buy in bulk, dramatically lowering its cost compared with the tiny packets of active dry yeast sold in stores.

• Extremely stable; can be frozen for several years
• Consistent behavior over time
• Tolerant of temperatures up to 130°F (54°C)
• Suitable for recipes that require more than one rise
• Suitable for cold-proofed doughs
• To use in place of active dry, incorporate directly into the dry ingredients. Add any ingredients used for proofing (warm water, sugar) to the dough along with other liquid ingredients.

Fast-Acting Instant Yeast

As a subcategory of instant yeast, fast-acting yeasts are likewise stable and easy to use, but formulated to operate on an accelerated timetable, making them unsuitable for recipes that require a long rise. Whether you're using RapidRise (from the Fleischmann's brand) or Quick-Rise (from Red Star), it's important to remember that these yeasts are defined by their trademark rather than by some objective measure, so their behaviors can vary wildly.

• Highly stable; can be refrigerated up to one year
• Consistent behavior over time
• Tolerant of temperatures up to 130°F (54°C)
• Designed to work with only one rise
• Not suitable for refrigerated doughs
• Not suitable for doughs with a long, slow rise
• To use in place of instant dry yeast, proof at cool room temperature, and follow the recipe's visual cues (such as letting the dough double in bulk) rather than a specific timetable. To use in place of active dry yeast, incorporate directly into the dry ingredients. Add any ingredients used for proofing (warm water, sugar) to the dough along with other liquid ingredients.

Compressed Fresh Yeast.

Rarely found in the United States, this kind of yeast has a much higher moisture content, up to 70 percent, and is sold in blocks. It must be refrigerated to stay fresh, and even then it is only usable for two weeks. Store it in the freezer and it will stay fresh up to six months.