Baker's yeast is comprised of microorganisms (known as « yeasts ») that allow dough to rise. When the dough is resting, the yeasts convert the sugars in the flour into carbon dioxide. This gas takes the form of small bubbles, which are trapped in the dough and cause it to rise. After baking, these bubbles give the bread a spongy crumb.

Fresh baker’s yeast can be bought in compressed or cake form at a bakery, but also in the fresh food section of certain supermarkets. Dried baker’s yeast, or instant yeast, is found in envelopes (sachets) in the baking section of supermarkets. There is also active dry yeast, which comes in the form of small pellets packed in a jar. It has to be dissolved in water before using it in the same way as fresh yeast.

Compressed fresh yeast is crumbled and dissolved in lukewarm water or milk before being added to the rest of the ingredients. Instant yeast does not need dissolving and can be added directly to the dough. Fresh yeast must never come into contact with salt, which would make it inactive. On the contrary, sugar stimulates the effect of yeast when it is added to the dough in small amounts.

The microorganisms making up yeast are destroyed at temperatures above 50°C. When this temperature is reached, fermentation stops and baking begins. This process “fixes” the air bubbles in the dough and gives it an airy texture.

Baker’s yeast lets you make any dish that requires leavened dough, such as pain de campagne, brioche, pizza, baba, and fritters. An envelope of instant yeast or 12 g of fresh yeast is enough for 250 g of flour.

Fresh yeast will keep for one week in the refrigerator if carefully wrapped to prevent it from drying out. It can be frozen for several months and should be left to thaw in the refrigerator before use. Instant yeast in envelopes will keep for several months away from heat.

Premium subscription

Gain unlimited access to 1,000 recipes from the greatest chefs
starting from just 1$

Discover top chefs recipes, with step-by-step illustrations and videos

Learn tips and tricks from the greatest chefs

Master techniques at home with interactive videos

Cancel anytime