1. Raw materials and auxiliary products
Malt:
It is recommended to use malt with a protein content of 9% to 12%. Its high-molecular protein can decompose products to facilitate foaming, but it will also increase the possibility of beer turbidity.
Yeast:
It is advisable to use yeast with a short shelf life, fermentation capacity, and vitality, and reduced generation.
Brewing water:
The higher the residual alkalinity of the water, the better the carbonate solidification effect, and the higher the pH value, the greater the impact on the bubbles. Most importantly, the content of metal ions in the water needs to be controlled, such as iron, nickel, and various other ions.
Hops:
Use fresh, high-quality hops to provide specific molybdenum, the most potent alpha-acid structure, and the lowest fatty acid content. Hops must be stored at low temperatures and under oxygen conditions to avoid alpha-acid oxidation and free fatty acid build-up.
Auxiliary basic materials:
Rice, corn, barley, and wheat are commonly used. Among them, the content of wheat glycoprotein is relatively high. Adding some wheat or wheat flour as auxiliary products helps improve the foaming efficiency of beer. Rice and cornstarch contain a certain amount of fat that breaks up beer foam.
2. Mashing process
Temperature has a significant effect on protein breakdown. For well-dissolved malt, the mash tank can be maintained at 52 to 55°C for 30 to 40 minutes to increase the high molecular weight and form foamed proteins, gelatin, and viscous substances.
A high concentration of saccharified mash, lower pH value, and stable enzyme activity benefit protein decomposition and the obtainment of higher polymer nitrogen.
The lauter tank should filter the clear wort, with the water temperature controlled at 75-76℃ and the pH value at 5.8-6.0. Excessive cleaning is prohibited, as it would produce a large amount of polyphenols and fatty acids into the wort, which will affect the beer foam.
When boiling the wort, add a certain amount of hops to extract about 20ppm of isohumulones through cooking, which directly promotes foam formation. The longer the boiling time, the higher the yield of isohumulones, the slower the nitrogen aggregation rate, the increased volatilization of hop oil, and the poor stability of melanoidin foam.
The wort should have sufficient clarification time in the whirlpool tank before cooling to promote the complete elimination of heat condensation and ensure that any condensed fat is distributed in the fermentation broth and directly enters the beer, which may cause poor foaming.
Use a bottom pump mash, adjust the mixer’s speed, etc., to prevent oxidation of the mash and wort, maintain a specific amount of polyphenols, and aid beer foam.
