White Labs WLP004 Irish Pale Ale is a liquid yeast from one of the oldest stout producing breweries in the world. It produces a slight hint of diacetyl, balanced by a light fruitiness and slight dry crispness. This yeast is great for Irish ales, stouts, porters, browns, reds, and a very interesting pale ale. White Labs is world-renowned for quality and innovation, certified kosher, GMO free, and subject to thorough quality analysis before being packaged.