Fermex (Worcester) supplies a frozen yeast product with characteristics similar to dried and fresh yeasts, but also a number of advantages over both, particularly when used in frozen dough applications. Like dried yeast, it is free-flowing, even at –20°C, is unaffected by oxygen and moisture, so vacuum-packed storage is unnecessary, says the company.Fresh yeast normally has a shelf-life of around four weeks when stored at 4°C and in conventional bakery production works satisfactorily throughout its shelf-life. However, when used in frozen dough, particularly when sugar is present, the effect of the age of the yeast can reduce the long-term storage quality of the frozen dough. This is not the case with Fermex F3 yeast, claims the company. The yeast remains in peak condition throughout its shelf-life in frozen storage. It has the same gassing power of traditional yeast and so is especially useful in ensuring consistency of final product, says Fermex.The shelf-life of frozen dough products is adversely affected if fermentation commences before the freezing process. Fermex F3 yeast contains approximately 75% solids, compared to about 30% solids in fresh, compressed yeast. This reduced moisture content means the onset of fermentation is delayed as Fermex F3 yeast has to absorb water, first.In addition, dough temperature can be kept to a minimum as Fermex F3 is added directly to the mix in frozen form, and does not suffer the “cold shock” that can reduce shelf-life of frozen dough products made with dried yeasts, says the company.The strains of the yeast are also specially selected to ensure optimum stability of fermentation power.