We would like to dispel the myth that fresh yeast produces better bread than dry yeast. In fact-if used properly-dry yeast will produce the exact same bread as fresh yeast. As long as the amounts are correct, the process is the same. It may even be the better choice in some situations, especially when you do not have a reliable source for fresh yeast. And, even if you do, instant yeast is a good back-up to have on hand in case you run out of fresh yeast. An unopened package of instant yeast has a shelf life of up to two years.
Active dry can be used at 50% of the weight of fresh yeast and instant dry can be used at 40% of the weight of fresh. Based on the recommendation of the yeast manufacturers, most people are under the impression that 33% is the proper conversion for instant yeast. This is true for an industrial process, but 40% is better in the artisan process, when dough temperatures are generally lower.
The instant form is the easiest to use since it does not need to be re-hydrated before adding to the dough. The only precaution is that it should not come in direct contact with cold temperatures and therefore should be mixed into the flour before adding water or added after the flour and water is incorporated.
Fresh yeast to dry yeast conversion and vice versa
The packaging types, sizes and measuring systems aren’t the only thing needing conversions. If you only have dry yeast and the recipe calls for fresh yeast, what do you do? Fresh yeast to dry yeast conversion and other way round is an easier one. Very often I read in different recipes suggestion to half or double the amount to change the type of yeast. That would result in too much of dry yeast of too little of fresh and longer proving time.
The rule of thumb is dividing or multiplying by 3:
from fresh yeast to dry – divide amount by 3, eg. instead of 30 grams of fresh yeast use 10 grams of dry
from dry yeast to fresh – multiply by 3, meaning 7 grams or dry yeast becomes 21 grams of fresh.
Another easy way to remember yeast conversion is:
10g of fresh yeast = 1 teaspoon of dry yeast
10 : 3 = 3.33 g
As you can see above, this is close to 3.5 g – the average weight of one level teaspoon of dry yeast. Teaspoon volume varies depending on the manufacturer and the shape. However, a few grams more or less of yeast won’t make a huge difference in your recipe.
The amount of dry yeast in recipes and on the packaging instruction is often exaggerated. As a result the dough rises too quickly and has a yeasty taste. Reduce the amount of yeast and allow the dough a bit of extra time if necessary.