(Wallerstein Laboratory) WL Nutrient (WLN) Agar is a selective and non-differential medium used for the cultivation of yeasts, molds, and bacteria encountered in brewing and industrial fermentation processes. WLN was developed by Green and Gray while studying various fermentation processes. An exhaustive study examining methods of fermentation control procedures in worts, beers, liquid yeasts, and similar fermentation products led to the development of WL Nutrient Medium. At a pH of 5.5, counts of viable baker’s yeast will grow. Plates are incubated aerobically to obtain a total count of yeasts present.• Product meets ASBC and ASM reference methods and performance criteria.• WLN Agar should be used by trained professionals within a laboratory setting. • Product is not intended for use in the diagnosis or treatment of disease or other human conditions.