Yeast

Difference between active dry and instant yeast: active dry yeast needs to be proofed in warm water. Instant yeast does not.

In a recipe that calls for active dry, you can use 20% less instant yeast instead, still adding the liquid that it calls for for proofing the yeast.

In a recipe that calls for instant yeast, you need 20% more active dry yeast--proof it before adding it to the other ingredients. Also, you should reduce the amount of liquid you add later in the recipe by the amount of water you proof the yeast in.

(correct me if I'm wrong, but this is how I understand it)