Yeast extract is a seasoning that appeals to the receptors for the basic umami taste. It therefore serves an important culinary function. Every chef is aware that the taste of a dish can be enhanced by sprinkling a pinch of sugar or salt over it. Similarly, a small amount of yeast extract adds the umami taste highlighted in Laura Santtini´s cookbook. This is especially important for vegetarians or vegans. Often the cooking times of their dishes are shorter and hence the glutamic acid is released from the proteins in smaller quantities. In this case, natural yeast extract can be used to provide an intense umami flavour.
Yeasts are single-cell microorganisms classified as fungi that multiply rapidly by means of cell division. For centuries, they have been used specifically in food and drink production, for example in beer brewing and bread making. Yeast extract is made from brewer’s or baker’s yeast. The yeast extract production process is similar to baking. Sugar is added to fresh yeast, which is then allowed to grow under optimal conditions: a temperature of 30 degrees Celsius and a sufficient supply of oxygen. This results in a viscous, creamy yeast mass.
The next step involves obtaining yeast extract: with a heat treatment, the yeast’s own enzymes break down the yeast protein into its components – amino acids and peptides. The enzymes also make the cell walls permeable, thus allowing amino acids, peptides, minerals and vitamins to leave the yeast cell and blend with the surrounding liquid. The resulting mixture already tastes like a savoury bouillon.
In the final stage of the yeast extract production process following autolysis, the yeast cells are removed mechanically with a centrifuge. What remains is yeast extract: a liquid that has an amino acid profile very similar to that of a cooked meat stock and still contains valuable vitamins and minerals. In simple terms, yeast extract contains all the natural components of the yeast cell without the surrounding cell wall. Finally, the yeast extract is concentrated into a paste or a liquid in a gentle evaporation process at around 60 degrees Celsius or all water is evaporated through a spray drying process. The final product is then ready to be transported to food producers who use the ingredient to season their products.
