Esters are the main component of beer aroma substances, only a little in beer, but they have a great impact on the taste of beer. The right amount of esters gives a beer a full-bodied taste; however, too much can give an unpleasant bitterness and aroma to the beer.
The amount of esters in a beer depends largely on the original gravity of the wort and the type of beer.
In top-fermented beers, ester levels can reach 80 mg/l.
In bottom-fermented beers, the ester content can reach 60 mg/L.
(1). Yeast strain
In general, top-fermented yeast will cause more esters than bottom-fermented yeast. This is because wheat beers have a strong estery aroma.
(2). Fermentation temperature
High fermentation temperatures favor the formation of esters. If the temperature is increased from 12.5°C to 25°C, the concentration of ethyl acetate will increase by 60%; the concentration of isoamyl acetate by 30%.
(3). Fermentation pressure
The higher the pressure, the higher the ester content, which is caused by the higher liquid pressure at the higher tank.
(4). Composition of wort
Amino acids and fermentable sugars in the wort affect the formation of esters. Amino acids favor the formation of esters, while fermentable sugars do the opposite.
(5). Processing measures
All measures that contribute to yeast multiplication promote ester formation.
(6). Beer storage time
Longer storage times will produce more esters, even if the effect is very small.