Tom is in the middle of AIB’s Pizza Production workshops this week so he may be a bit behind on answers. In the meantime, here is some info I have located from past articles he has written that may help.
Active dry yeast can be used as a substitute for the compressed yeast. It is used at half of the compressed yeast level. Make sure you pre-hydrate the ADY in water at 105F for 10 minutes before you add it to the dough (get a good thermometer). When putting together your formula, put the water in the mixing bowl followed by the yeast, then add the flour, and the dry ingredients and the softened butter.Then mix the dough in your normal manner.
Tom Lehmann/The Dough Doctor
Question:
I’ve heard you recommend that the yeast not be put into the water with the salt and sugar, why is this?
Answer:
Both salt and sugar can exert a great osmotic pressure (they impede the ability of the yeast to absorb nutrients through the yeast cell wall/membrane). This effect can impair the ability of the yeast cells to feed, and under certain conditions (high salt and sugar and little water) it can actually exert a very damaging, evicerating affect upon the yeast cells where the liquid contained within the yeast cells is pulled out into the salt/sugar water. If this isn’t bad enough, contained within that liquid is the amino acid, glutathione. Glutathione is very similar in its effect upon dough as is L-cysteine, the active ingredient in many dough-relaxing agents such as PZ-44. So, by mixing your yeast, salt and sugar together in the water you stand a good chance of impairing the ability of your yeast to function at its best plus you also stand a chance of possibly getting a softer dough than you had bargained for if any glutathione should be leached out from the yeast cells. This is why we like to “play it safe” and recommend that the yeast always be kept separate from the salt and or sugar until they are all incorporated into the dough. The only real exception to this is in the case where active dry yeast (ADY) is used. In this case it is sometimes recommended that just a very small amount of sugar be added to the warm water in which the yeast is being hydrated/activated. In these small quantities, no harm will come to the yeast.
