Yeast, ahhh, patience. Which type do you use? GKC uses all types and had to demystify them for our GKC friends.
Fresh yeast, also called cake or compressed yeast, is perishable and it is not unusual to buy a block that is dead (I always buy one extra when I’m using it). The flavor is bold and fresh and I love it in challah baking. The water used to activate the yeast should be 80 – 90 degrees. You do not need to add sugar during the proofing process. Remember to keep it refrigerated until use and buy it only a few days before needed.
For less maintenance and sensitivity, we recommend using active dry yeast, which is more reliable and easier to use. Granulated active dry yeast is made by putting yeast on a dryer to remove 90 percent of its moisture. It’s a harsh process that produces many dead yeast cells, which form a hard coating around each granule. That’s why the granules must be proofed or soaked in water at a temperature of 100 to 115 degrees before they are used. This process dissolves that coating and awakens the active yeast within.
Instant, or Rapid Rise Yeast requires no proofing. The drying process for this kind of yeast, developed in the 1970’s, is gentler so that fewer cells are killed and the yeast is faster acting and can be added directly to dry ingredients. The liquid you add to make the dough should be warm, 110 to 130 degrees to activate it. It is more potent so you should use less (3/4 of a teaspoon to a single teaspoon of active yeast).
Both types of dry yeast keep up to a year at room temperature. And all types will be killed with water above 132 degrees. For faster challah making try the rapid rise yeast; just dump and stir all ingredients together. And for extremely fresh bread tasting recipes try the fresh yeast. When in doubt, you can always use the active dry yeast. Remember to “feed” both fresh and active dry yeast with a teaspoon of sugar to start the proofing.
Yeast Conversion Rates
To substitute rapid rise yeast for active dry yeast, use 25% less instant yeast than active dry.
A .6-oz cube of cake yeast is roughly equivalent to 1½ to 2 teaspoons rapid rise yeast or 2 to 2¼ teaspoons active dry yeast.
Each little .25-ounce packet of active dry yeast contains about 2 1/2 teaspoons of yeast.
How to Proof Yeast
To proof (either type of dry yeast), dissolve in warm water (100 to 115 degrees), feed it with a teaspoon of sugar and wait for it to bubble and grow in volume. Let it stand for 10 minutes until creamy and bubbly.
Adequate “proof” is visible bubbles (a by-product of yeast multiplication) or a “yeasty” smell or froth at the top of the liquid. I like yeast to puff up about 3 inches or double in size.