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yeast questions

"Schmitt, Barbara E." <BSchmitt@goulstonstorrs.com>
Mon, 19 Aug 2002 08:30:08 -0400
v102.n036.1
You have both asked for some basic information on yeast, so let me see if I 
can help.

Active dry yeast is the yeast that comes in the little envelopes in the 
supermarket.  It works fine, but if you bake a lot of bread, it gets expensive.

Instant yeast is usually bought in larger quantities, and often comes in a 
vacuum-sealed "brick" or in a jar (sometimes labeled bread machine yeast).

They measure virtually the same, teaspoon for teaspoon -- my experience is 
that the difference is so small, it is not worth trying to make any 
adjustments.  One packet of active dry yeast equals about 2 1/4 to 2 1/2 
teaspoons of instant yeast.

They can be used interchangeably in recipes, with the following change:
Active dry yeast must be rehydrated in water before you use it (also called 
proofing).  The process is simple -- you mix the yeast with about 1/4 cup 
of the liquid from your recipe, warm to the touch but not hot.  Let it sit 
for about 5 minutes (if you are concerned that your yeast is no longer 
good, add a pinch of sugar; if the mixture bubbles after about 5 minutes, 
the yeast is good).  Then mix the yeast mixture in with the rest of the 
liquid in the recipe (be careful that the other liquid, if it has been 
heated, is allowed to cool to "warm but not hot" or you risk killing the 
yeast).  Instant yeast does not require rehydration, so you can just mix it 
in with your dry ingredients and proceed as usual.  Because it does not 
require mixing with water first, instant yeast works better in a bread 
machine, especially if there is a delay between when you add all the 
ingredients and when the machine starts.

As for storing instant yeast, I keep my unopened packages in the pantry; 
once open, I put them in a zipper bag in the refrigerator.  Some people put 
it in the freezer, but I have not had good luck with that.  I find it keeps 
fine in the fridge for at least 6 - 12 months.

Instant yeast can be purchased at some supermarkets (the bottles of "bread 
machine yeast"), in catalogs and specialty stores (the good old King Arthur 
catalog comes to mind) and, I have heard, occasionally from bakeries.

Do not confuse instant yeast with "Rapid Rise Yeast," which also comes in 
envelopes in the grocery store; this is a yeast that is formulated for 
making bread very quickly.  Some people like it, but my view is that bread 
made this quickly is not very good.

Hope this helps.  Keep on baking!

Barbara