Top-fermented
German: Obergärig
Fermentation method with yeasts working at 15 to 24 degrees Celsius that collect at the top of the vessel.
In top fermentation, yeast strains (Saccharomyces cerevisiae) are used that are most active at about 15 to 24 degrees Celsius and gather on the surface of the wort toward the end of fermentation. It is the older of the two fermentation methods.
Top-fermented beers are often fruitier and more aromatic because the yeast forms esters and further flavour compounds. Fermentation usually takes only a few days and maturation is often shorter than for bottom-fermented beers. Top-fermented styles include wheat beer, Kölsch, Altbier, ale, stout and many Belgian beers.