Not all types of yeast are created equal. The different types of yeast used in baking, cooking, and brewing have characteristics that suit a certain application. While some types of yeast can be used interchangeably if you tweak the recipe, others are so different that they don't work for all purposes. When shopping for a particular recipe, make sure you buy the right version.
Types of Yeast Used in Baking
"Baker’s yeast" is the general term given to all forms of Saccharomyces cerevisiae used to make bread products. Baker’s yeast is available in several forms such as active dry, fresh (or cake), liquid, and instant.
- Active Dry: This yeast requires dissolving it in warm liquid prior to adding to a recipe and should not be substituted with or for instant yeast. Active Dry yeast should not be exposed to liquids hotter than 110 degrees Fahrenheit, or else it will kill off the yeast, a live culture. This yeast is usually sold in 1/4-ounce envelopes or 4-ounce jars.
- Fresh: Fresh yeast is sold in compressed or cake form. This type of yeast is extremely perishable, so it must be kept refrigerated and used within a couple of weeks of purchase. To use fresh yeast, it must be dissolved into a liquid prior to adding to a recipe. Fresh yeast should be proofed, or tested for potency, before each use. To proof yeast, dissolve in warm water and add a pinch of sugar. If the yeast does not begin to foam within 5-10 minutes, it is no longer active.
- Liquid: This was the most popular form used prior to the invention of compressed or cake yeast in the early 19th century. Liquid yeast is basically a slurry of live yeast organisms, flour (or other carbohydrates), and water, similar to a sourdough or bread starter. As long as fresh carbohydrate is added on a regular basis, the organisms will continue to live and replicate.
- Instant: Instant yeast is the most active form that's commercially available. This yeast does not require dissolving into a liquid before adding to a recipe and often only requires one rise. This form of yeast is very shelf-stable and can be stored in a dry, airtight container at room temperature until the expiration date. Instant yeast can be referred to also as rapid rise or bread machine yeast. Labeling instant yeast as “bread machine yeast” makes it easier for consumers to choose the correct yeast to use in their bread machines.
Types of Yeast Used in Cooking
Although yeast extract is technically a type of nutritional yeast, it's used in a very different manner. Therefore, they can be treated as two separate products.
- Nutritional Yeast: This is a deactivated form of yeast, which is used as a nutritional supplement. The deactivation of yeast is important because consuming large quantities of live yeast organisms can lead to proliferation throughout the body. Deactivated yeast is a good source of minerals and B vitamins. Nutritional yeast has a nutty or cheese-like flavor and is often used as a topping or seasoning for foods.
- Yeast Extract: This is a concentrated nutritional yeast product often in the form of a paste. Yeast extracts are favored for their pungent, umami flavor. Yeast extracts have a wide variety of uses and have developed a cult following around the world. Popular brands of yeast extract include Marmite and Vegemite.
Types of Yeast Used in Brewing
Brewer's yeast is the variety used to make beer. Several types of yeast are used to brew beer, each lending its own flavor and texture characteristics.
- Top-Fermenting Yeast: Also known as ale yeasts, top-fermenting yeast rises to the surface during the fermentation process of beer-making, which creates a rich, thick head. This yeast should be used at temperatures ranging from 50 to 77 degrees Fahrenheit, or 10 to 25 degrees Celsius.
- Bottom-Fermenting Yeast: Bottom-fermenting yeast is also known as lager yeast, which should be used at temperatures between 44 to 59 degrees Fahrenheit, or 7 to 15 degrees Celsius. The yeast grows more slowly than the top-fermenting kind and doesn't create at much foam. It also settles to the bottom of the fermenter as the process ends.