White Labs WLP017 Whitbread Ale Yeast is a traditional mixed yeast culture with British style character that is slightly fruity with a hint of sulfur production. This yeast can be used for many different beer styles, with the most traditional choices being English style ales (including milds, bitters, porters, and English style stouts). North American style ales will also benefit from fermentation with this yeast. This yeast comes packaged in White Labs' PurePitch packaging using the revolutionary FlexCell process, which creates yeast that has never been transferred or exposed to the environment. The PurePitch packaging is a recyclable, flexible material that allows for increased breathability, reducing the chance of gas buildup and maintaining the optimal environment for yeast.