top-fermenting
Adjective
Meaning
top-fermenting (not comparable)
Pertaining to any of numerous edible yeasts that produce, e.g., ale, and whose respective fermenting actions appear to be at the top surface of the wort.
Examples
As such, the yeasts involved in what has been typically called top-cropping or top-fermenting ale may be both Saccharomyces cerevisiae and complex hybrids of Saccharomyces cerevisiae and Saccharomyces kudriavzevii.
By the late 18th century, two yeast strains used in brewing had been identified: Saccharomyces cerevisiae (top-fermenting yeast) and S. carlsbergensis (bottom-fermenting yeast).
Lager yeast can be fermented at a higher temperature normally used for top-fermenting yeast, and this application is often used in a beer style known as California Common or colloquially as " steam beer ".
These vessels have no tops, which makes harvesting top-fermenting yeasts very easy.