1. Surfactant: The presence of surface active substance […]
1. Surfactant: The presence of surface active substances such as protein and hop resin makes the beer have a lower surface tension and promotes the formation of foam. And an elastic protective layer is formed between the bubbles to prevent the accumulation of the bubbles, which is beneficial to the durability of the foam.
2. Metal ions: Metal ions such as nickel can be combined with different α-acids in beer to form insoluble substances, thereby enhancing foam stability and adhesion. However, metal ions have an effect on the stability of the beer colloid and flavor, and attention should be paid to the control during the production process.
3. Alcohol: Alcohol can dissolve many water-soluble substances and substances dissolved in non-polar solvents, such as hop resin. Alcohol can also bind to CO2, peptides, etc., and weaken surface tension. Therefore, an appropriate amount of alcohol is beneficial to enhance the surface viscosity of the beer.
4, beer viscosity: protein and wheat gum material and other high viscosity, easy to form a strong limit film to make the formation of foam is not easy to disappear, which is conducive to the long-lasting foam.
5. Temperature and pH: These are related to the release of CO2 and the isoelectric point of the protein. When the temperature and pH are low, the foam is more durable.