A slow-rising yeast, brewer's yeast is often used to make beer because it produces small bubbles and adds to the fermentation of the beer's brewing ingredients. Brewer's yeast is often referred to as beer yeast. Do not confuse it with a nutritional inactive yeast also known as brewer's yeast, which is the often-bitter yeast product that remains after the fermentation of alcohol. Brewer's yeast is often used when a baker wants to add more flavor to bread, but active dry yeasts such as Red Star baking yeast can be substituted for brewer's yeast with ease.
Consult your recipe. Check to see how much brewer's yeast the recipe requires. Brewer's yeast causes bubbles in fermented beverages such as beer and is sometimes used in baking because of its strong yeasty flavor. Brewer's yeast works differently than baker's yeast by producing ethanol and not the carbon dioxide made by active dry baking yeasts such as Red Star. Yeasts that produce carbon dioxide work faster than ethanol-producing yeasts.
Substitute a little less than half of the active dry yeast for the brewer's yeast, since the active dry yeast is a more concentrated form. If the recipe calls for 1 ounce of brewer's yeast, use a bit less than a half-ounce of baker's yeast. Remember that brewer's yeast and baking yeast are the same strain of yeast fungi, but they grow at different speeds. Brewer's yeast is much slower than baking yeast. You will require less of the dry active yeast, which is made for a rapid one-rise recipe.
Dissolve the active dry yeast in warm water that is no more than 110 degrees Fahrenheit. This reactivates the yeast culture, which has had its water reduced and been rendered temporarily inactive. Add a pinch of sugar to the warm water to stimulate growth of the culture.