yeast
Also Known as
Dry yeast
Description
Yeast is a one-celled fungus (a living organism) that exists in many forms. For baking (fermentation) purposes, it produces carbon dioxide when mixed with warm water, flour, salt, and/or sugar, which cause expansion in dough. Yeast is a one-celled fungus that converts sugar and starch into carbon dioxide bubbles and alcohol. This has made it a useful ally in the production of bread, beer, and wine.
There are many varieties of yeast:
· Active Dry/Rapid Rise/Bread Machine - These are often referred to as baker's yeast.
· Active Dry - The most commonly used and recommended for hand-kneaded dough. Available in 1/4-ounce, 3-strip packets and 4-ounce jars.
· Rapid Rise and Bread Machine yeasts - Fine-grained. Will cause a "single-rise" reaction, which makes them more efficient in machined dough. Rapid Rise is sold in 3-strip packets and Bread Machine yeast is sold in 4-ounce jars.
· Cake Yeast/Fresh Active - Foil-wrapped, compressed square cakes. Two sizes available: 2 ounce and .06 ounce. Cannot be used in bread machines. This type is typically used by commercial bakers.
· Wild Yeast - This is the "starter" that many cooks keep alive in a crock. Each week, 75% of the starter is replaced with water and flour to keep it growing. The live yeast that is removed is used for baking or discarded. Most artisan breads are made from wild yeast. Starter or sponges are not as reliable as packaged or cake yeasts.
How to Select
Yeast comes in envelopes, jars or bulk and can be regular or quick rising. Quick rising will half the time needed for rising to occur. Because you are purchasing live organisms, please note the expiration date on the package when using (fresh yeast will only last 1 week).
Culinary Uses
· Bread is made with baker's yeast, which creates lots of bubbles that become trapped in the dough, making the bread rise so it's light and airy when baked.
· A small amount of alcohol is also produced, but this burns off as the bread bakes.
· Beer yeast and wine yeast are used to convert sugar into alcohol and, in the case of beer and champagne, bubbles.
· Yeast needs both a warm environment and food to grow. The process is often called "proofing the yeast." Yeast should be dissolved in warm water (100-110 degrees F), but not hot water or it will die. Sugar is usually added to "feed" and grow the yeast. You should see activity within 5 minutes, bubbling and expansion during yeast activation. If you see no activity, your yeast is too old; the water was too warm or too cold. Time to start over Yeast for bread-making can be fresh, dried or 'easy-blend', but in all cases it is a living organism that needs moisture, warmth and food (such as sugar or flour) to grow. As yeast grows, it produces carbon dioxide, which makes the dough expand and rise. In general, slowly risen dough results in bread with superior flavour and texture.
· Extreme heat kills the yeast, which is why the dough stops rising when it's baked in a hot oven. You should never use very hot water to mix dough because it will kill the yeast and stop the dough from rising.
· You should never eat raw active yeast, since it will continue to grow in your intestine and rob your body of valuable nutrients. But once deactivated through pasteurization, yeast is a good source of nutrients.
How to Store
Always store in a cool, dry place, preferably the refrigerator (a must for fresh yeast), but bring to room temperature before using. Fresh yeast is extremely perishable and should be used within 1-2 weeks or date on package.