Here's some yeast info on both those strains (from Jack Keller's site):
Epernay : Epernay is a Champagne yeast, meaning it was isolated in Champagne, France and is used in Champagne production. Epernay is used in bottle fermenting because it ferments slowly and is tolerant to cold temperatures with moderate foaming. It is also used for primary fermentations of still white wines.
Lalvin EC-1118 (Prise de Mousse) : This is the original, steady, low foamer, excellent for barrel fermentation or for working on heavy suspended pulps. It is one of the most popular wine yeasts in the world. It ferments well at low temperatures, flocculates well, and produces very compact lees. It is good for Champagne bases, secondary (bottle) fermentations, restarting stuck fermentations, and for late harvest grapes. It is also the yeast of choice for apple, crabapple, cranberry, hawthorn, and cherry wines. It has excellent organoleptic properties and should be in every vinter's refrigerator. Alcohol toxicity is 18% and it ferments relatively fast. It tolerates temperatures from 39-95° F. It is not, however, tolerant of concurrent malolactic fermentation.
Hope that helps. Regards, GF.
