Different yeasts were employed in the production of lagers or ales. For instance, lagers were produced using
bottom-fermenting yeasts, Saccharomyces uvarum (Carlsbergenesis), at a fermentation temperature ranging
between 7 and 150C. This method was quite distinct from the production of ales, which used top-fermenting yeasts,
Saccharomyces cerevisiae, at a high fermentation temperature range of 18-220C. In this case the yeasts accumulate on the surface of the fermenting wort where they can be skimmed. Lagers tend to be darker in color as well as less bitter than
ales, which are much paler in color.