15 grams of fresh yeast is equivalent to 7.5 grams of dry yeast. Normally, the conversion ratio of fresh yeast to dry yeast is 1:2, i.e. 1 gram of dry yeast is equivalent to 2 grams of fresh yeast. This is because fresh yeast contains more water, whereas dry yeast is dehydrated and therefore has a relatively high content of active substances. Please note that the actual conversion ratio may vary depending on factors such as different brands, different recipes and different environmental conditions. Therefore, in actual use, it is recommended to determine the amount of dry yeast according to the requirements of specific recipes. Yeast is a microorganism that ferments sugar into alcohol and carbon dioxide. It is a typical heterotrophic parthenogenetic anaerobic microorganism that is widely distributed in nature. The fermentation of yeast in dough is mainly to use the carbon dioxide produced by yeast cells to make the dough rise and expand, and at the same time to produce unique flavor substances, so that the fermented food has a unique color, aroma, taste and soft and fluffy texture. Yeast can be used in brewing production, such as flour, wine, sauce, etc., but also as a model organism for genetic engineering and cell cycle research.