American (Sierra Nevada). Activator pack. 100 billion cells. Used commercially for several classic American ales. This strain ferments dry, finishes soft, smooth and clean and is very well balanced. Flocculation: low to medium, apparent attenuation: 73-77%, 60-72 deg F. 125 ml XL packets contain 5 times the amount of yeast as a regular Wyeast package. There is enough yeast to pitch 5 gallons of wort without incubation or 15 gallons with incubation.