Fermentation : Dry yeast, fresh yeast and sourdough

Who were the first bakers in history?

It is believed to be the ancient Egyptians and that they used starch flour. But what about their breads, were they made with leaven or yeast? And what's the difference between the two?


Active dry yeast

It is the ideal yeast if you are new to making bread. Easy to use, it can be stored for several months (up to two years when refrigerated). This is the same substance as fresh yeast, it is simply dehydrated and broken into small balls.

Brand: Fleischmann’s (traditional, bread, quick, pizza)

Where to find it: all grocery stores


Fresh yeast

Also called organic yeast or baker's yeast. It is in fact a microscopic fungus which, by consuming the starch present in the flour, will produce the gases which will make your dough rise. With a moist texture, similar to butter (it looks like a large block of compact tofu), it can be stored for 10 to 20 days in the fridge. It is recommended to dilute it before using it, that is to say that it should be diluted in a lukewarm liquid.

Where to find it: several bakeries, including the Automne bakery


The leaven

What exactly is it? It is a mixture of water, flour, sugar or honey. After natural fermentation for about 10 days, it can be used for bread making. It should be fed every day, adding a little flour and water. Just like a plant, it will require minimal love and maintenance from you. The touch of acidity it will add to the taste of your bread is well worth it, however. The more so as it allows the bread to be stored longer and it is easier to digest than yeast.

Where to find it? The leaven can be split (from someone who gives it to you) and you can feed your new master leaven to keep it going. Want to start yours? Follow the links below:


Do it yourself: where to start?

Here is a step-by-step recipe to start your sourdough. By Andrew Janjigian (resident baker for the Cook's Illustrated magazine):



In video:

L’Épicerie (SRC) - The art of sourdough

And the bread of the Egyptians in all this?

Legend has it that an ancient cook left his cereal paste in a ceramic casserole dish. The dough would thus have had time to ferment and become the first leavened bread in the world. Was this bread seeded with sourdough or did it ferment spontaneously, thanks to the yeasts present on the poorly washed casserole dish? Impossible to know, but oh how fascinating!

Guillaume Ganivet-Boileau
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