First, the main constituents of beer foam 1. Protein: T […]
First, the main constituents of beer foam
1. Protein: The protein of the protein long-distance distinction between A and B is one of the main constituents of beer foam. In particular, the nitrogen-containing substance in B-division is the basic substance for forming a good foam. These proteins are capable of forming a protein bubble membrane that is viscous, elastic and airtight.
Polypeptides affect the foam in the form of glycoproteins, which have a surface active effect, increase the viscosity of the vacuole, and reduce the rate at which the vacuole falls into a liquid. Moreover, the sugar in the glycoprotein can protect the polypeptide from precipitation loss during the brewing process. The greater the hydrophobicity of the polypeptide, the more stable the foam formed, and the larger the molecular weight of the polypeptide in the relatively identical range, the greater the stability of the foam.
2. Isophorone: It is formed by isomerization of humectone in the hops when the wort is boiled, which can improve the hanging cup of the foam. Studies have shown that isohumulone with a certain negative charge can be ionically bonded to a positively charged polypeptide, which is the main body of beer foam.
3. CO2: Beer foam is actually a dispersion formed by the release of CO2 gas contained in itself in a colloidal solution containing protein or the like. The fine bubbles give the beer a certain consistency, fineness and softness, which improves the dispersibility and flavor. The CO2 content not only affects the release rate of the surface gas, but also affects the volume and foam density of the foam. Foams with a diameter of 0.2 mm are generally considered to be optimal.