YPD (YEPD) is a nutritionally rich medium for the growth of S. cerevisiae, containing only, peptone and yeast extract, without dextrose. This is useful for variations of YPD requiring alternate carbon sources. Glycerol can be added as a non-fermentable carbon source to make YEP-glycerol (YEPG) for the study of respiratory deficient mutants. Yeast extract and peptone provide carbon, nitrogen, minerals, vitamins, trace ingredients and other essential growth nutrients which stimulate the growth of yeasts.