There's a baking frenzy at the moment and many people are making their own sourdough bread. I'm a fan of traditional yeasted breads and always use fresh yeast for my bread. I generally pick some up from the bakery department at the supermarket (just ask, they'll always give you a piece.) Lot's of people have been asking me about the different types of yeast available; how to know what and how much to use in recipes. There are three main types but you bet your life that you will have a different type than specified in the recipe
Fresh yeast which must be kept chilled, will store for a couple of weeks in the fridge and also freezes nicely. Fresh yeast needs to be activated in liquid with a little sugar in order to start the fermentation. If a recipe asks for active dried yeast and you only have fresh yeast then you must double the quantity. See below.
Active dried yeast is a dried form of fresh yeast and will also need activating in the same way as fresh yeast. Active dried yeast does not need to be refrigerated.
Instant or Quick dried yeast can be added directly to the dry ingredients in a recipe and does not need activating. It is best to check the manufacturers instructions if using this.
Amount to use - 20g of fresh yeast = 10g of active dried = 5g of instant dried.
1 tsp of Active dried yeast is 3.5g.