There's dry yeast and fresh yeast. Dry yeast is what you will see in every grocery store and it comes in little square envelopes or small jars. This is by far the most popular and easiest way to go when baking bread at home. Fresh yeast comes in a square block and feels like moist putty, and it smells. It's mostly used in larger commercial bakeries where they need large quantities and they can use it quicker. Fresh yeat needs to be refrigerated and lasts only a few weeks at the most. Red Star Yeast is my favorite brand to use when it comes to baking bread. They have three different types of dry yeast to choose from depending on your recipe schedule, and a website filled with tips and information saving me from any disasters. I used their Platinum yeast which really sped up the rising process for my olive bread. I've used this recipe before with regular yeast and usually had to let it rise overnight. Not anymore, I can mix this dough together at lunchtime and have crackling hot olive bread on the table at dinnertime!