Influence of RA value of water on beer production process

The RA value of water will increase or decrease the pH value of mash and wort, which will have a series of effects on the production process of beer.

1.Effect on enzymes

In the process of saccharification, pH value has a significant effect on various enzymes, especially α-amylase. In the range of pH 5.2~5.8, the lower the pH value, the better the enzyme effect. When the pH value is high, α-amylase is inhibited, the saccharification time is prolonged, and the final fermentation degree is also reduced due to the inactivation of β-amylase. The viscosity of juice increases, and at the same time, endopeptidase decomposes only a small amount of soluble nitrogen, which slows down the rate of protein decomposition into amino acids; when the pH value is between 6 and 6.2, the activities of aminopeptidase and dipeptidase are almost completely lost; phosphoric acid The enzyme is also inhibited, so only a small amount of inorganic phosphate is decomposed from organic phosphate (such as calcium and magnesium phytate) and reacts with bicarbonate to form phosphate precipitation, resulting in a significant reduction in phosphate content in wort, reducing buffer capacity in the wort.

2.Effect on saccharification yield

As the action of enzymes is inhibited, the viscosity of wort increases, so there will be problems of difficulty in filtration and dirty washing, which can generally reduce the yield of saccharification by 2% to 3%.

3.Effects on wort properties

When the pH value of the mash is high, the first wort and lees wash will elute substances in the husk that are unfavorable to the taste, such as polyphenols with a high polymerization index, resulting in an increase in the color of the finished beer and an increase in the taste. Hard and thin; some proteins agglutinated under acidic conditions are unfavorable for agglutination at a higher pH value, which makes the beer easy to form turbid.

4.Influence on utilization rate of hop bitterness

When the pH value is high, the utilization rate of hops is high, but the bitterness is rough, and many substances harmful to taste are leached from the hops, which will make the beer have a stimulating taste. reduce.

5.Effects on fermentation

As mentioned earlier, a higher pH value in the mashing process will inhibit the action of many enzymes in the malt, resulting in insufficient amino acids in the wort and increased wort viscosity, which will also adversely affect fermentation. Insufficient amino acids will reduce the fermentation speed; high-viscosity wort often contains macromolecular proteins, these proteins are attached to the surface of yeast cells, causing the yeast to prematurely form lumps and settle down, so the true degree of fermentation of beer and final fermentation The degree of difference is large, the composition of the finished beer is not ideal, and the foam performance and stability are also poor.

The requirements of different beer varieties on the residual alkalinity RA value of water

The brewing of light-colored wine has higher requirements on water quality, and the RA value should be less than 0.89mmo/L. In theory, the RA value of water equal to 0.89mmol/L can meet the production requirements of light-colored beer, but with the pursuit of low-color beer, people hope that the RA value of water is lower or even negative. .