They use Ale Yeast.Their are hundreds of varietys of strains.Ale yeast is top fermenting.Their is also bottom fermenting yeast which is Lager yeast.Top-fermenting yeasts are used for brewing ales, porters, stouts, Altbier, Kölsch, and wheat beers.ager styles made from bottom-fermenting yeasts are Pilsners, Dortmunders, Märzen, Bocks, and American malt liquors. There are many different "strains" of yeast used in **** making. There are also several companies in the business of culturing yeast for sale to the home brewer. Off the top of my head, White Labs and Wyeast are probably the ideal brands to look for, with Wyeast being the most user friendly. They have "smack packs" which come with a nutrient/starter in the pack and you can tell if it's good yeast when the pack expands.