Yeast: Manufactured and Natural
Yeast produced for baking is a natural biological product manufactured industrially. It is often grown on molasses. It comes in two forms; fresh and dry. The long keeping properties of active dry yeast are beneficial over the three week shelf life of fresh yeast. This should be a consideration for when deciding whether to use fresh or dry yeast. On Vancouver island, the closest yeast manufacturer is in Calgary Alberta, therefore, it is not typical to use fresh yeast here. I usually use dry yeast in my formula's. To convert fresh yeast formula's to dry yeast use the following equation.
Sourdough starters are most intriguing. The science of sourdough is complex and even today, not fully understood. It appears to be a combination of ambient yeast and bacteria. The bacteria however vary from region to region. They also vary slightly in fermentation from bacteria to bacteria. Also the balance between "cold-loving" and "hot-loving" bacteria plays a role on the ph and flavor of a starter. There is much ongoing conversation about sourdough starters. Much of it takes place online. Visit this cool website to take part in some of that conversation, thefreshloaf.com
- (fresh yeast weight) X .4 = (dry yeast weight)
- Active - the yeast cells are in a latent state after being subjected to a low temperature drying process and must be reactivated. To do this rehydrate yeast in five times its weight in water at a temperature of 38C, along with a little sugar. After 15-20 minutes rest, the reconstituted yeast may be put to use. Do not use any more than 2.5% in your formula or a disagreeable "yeasty" flavor will be present in the finished product.
- Instant - this yeast has the advantage of being mixed directly into the flour. It has the advantage of being used in smaller quantities to yield a well leavened loaf with superior flavor. At temperatures of 27C 1% is sufficient.
Sourdough starters are most intriguing. The science of sourdough is complex and even today, not fully understood. It appears to be a combination of ambient yeast and bacteria. The bacteria however vary from region to region. They also vary slightly in fermentation from bacteria to bacteria. Also the balance between "cold-loving" and "hot-loving" bacteria plays a role on the ph and flavor of a starter. There is much ongoing conversation about sourdough starters. Much of it takes place online. Visit this cool website to take part in some of that conversation, thefreshloaf.com