Wort composition can affect ester synthesis, especially in high wort concentration brewing. High wort fermentations produced more esters than normal wort fermentations.
At present, most lager beers are produced by high-concentration brewing, which is prone to incongruity of beer flavors. The most prominent problem is that the esters are too high, resulting in beer with solvent and fruity flavors. The increase of acetates in high-concentration brewing was related to the characteristics of the strains, and the increase of esters produced by different strains was different.
Not only the concentration of the original wort has an influence on the formation of esters, but also the sugar profile of the wort has a great influence on the formation of esters. Generally speaking, wort with high glucose and fructose content is easier to ferment than wort with high maltose content to produce more acetates, and glucose and fructose are more easily absorbed and utilized by yeast than maltose. Compared with whole malt wort, ethyl acetate produced by buried fermentation using 30% high maltose syrup as an adjunct was 10% lower and isoamyl acetate 40% lower. Therefore, high maltose syrup is suitable for high-concentration brewing to appropriately reduce the ester content of high-concentration diluted beer.
In general, the higher the wort concentration, the more esters are formed. The high concentration of diluted beer contains more esters than the beer fermented with the same concentration, which will cause the flavor defect of the high concentration of diluted beer. Of course, by appropriately controlling the aeration of the high-concentration wort, the growth of yeast can be correspondingly increased, thereby reducing the ester content. In addition, through membrane treatment, the selective permeation of ethanol can solve its inhibitory effect on yeast growth.
