Safale S-04 Dry Yeast, English Ale. A well-known, commercial English ale yeast, selected for its fast fermentation character and its ability to form a very compact sediment at the end of the fermentation, helping to improve beer clarity. This yeast is recommended for the production of a large range of ale beers and is specially well adapted to cask-conditioned ales and fermentation in cylindro-conical tanks. Sedimentation: High. Final gravity: Medium.