I have a cinnamon roll recipe that calls for 7.5 lbs of high-gluten spring wheat bread flour along with 4.0 ounces of yeast. Since its an old recipe, I assume this is for compressed yeast. This flour/yeast ratio is where I need your opinion.
Originally, I was using 4 ounces of dry yeast but the rolls literally swelled out of the pan so I knew something was wrong. I am going to try about 1 to 1.5 ounces of dry yeast on my next run. Does this sound logical?-- Paul
Compressed yeast is fresh, moist yeast that is ready to use. It hasn't been dehydrated like active dry or instant yeast. Compressed yeast should be refrigerated until used. It will keep for about two weeks, or it can be cut into usable portions if necessary, wrapped in plastic and frozen for three or four months. Frozen compressed yeast should be allowed to thaw to room temperature before use.
The approximate substitutions between the three type of yeast are:
Reinhart (The Bread Baker's Apprentice: Mastering the Art of Extraordinary Bread) says that the typical ratio by weight of yeast to flour is 0.66% for instant yeast and 2% for compressed. There is a lot of leeway in this estimate, though.
Looking at your recipe, you had 7.5 lbs (120 oz) of flour and 4 oz of yeast. The weight of the yeast is therefore 4/120 = 3.33% of the weight of the flour. Given that ratio, as you suspect, your recipe was likely originally intended to use compressed yeast.
When converting from compressed yeast to instant yeast, you want to use ⅓ of the weight of the compressed yeast and make up the difference, ⅔ of the weight of compressed yeast, in water. For dry yeast, use about 7/16 of the weight of compressed yeast, but still add the same weight of water. For your recipe, then, you would use 1¾ ounces of dry yeast and add an extra 2⅔ ounces of water to the recipe. Because the ratio of yeast to flour in the original recipe was so high, your estimate of 1½ ounces of dry yeast would probably be good. Just don't forget to add the extra water to keep the percent hydration about the same. After you try these changes, you may still want to change the amounts of dry yeast and added water until you are happy with the recipe.