1. The harm of PH to enzymes. In the whole process of s […]
1. The harm of PH to enzymes. In the whole process of saccharification, pH value often has obvious harm to the action of various enzymes. The high residual pH of the water causes the pH of the mash to rise, which can reduce the specificity of the enzyme. For α-pepsin and some exopeptidases, in the lower pH range of 5.2~5.3, the lower the pH value of the mash, the better the enzyme effect; when the pH exceeds the suitable pH range of the "enzyme", if When α-pepsin is inhibited, the saccharification time will increase; if the specificity of β-glucanase is reduced and β-glucan is not scientifically dissolved, the viscosity of beer malt will increase; if endopeptidase is compromised, only The dissolution creates a small amount of soluble nitrogen, and the whole process of dissolving protein into carbohydrate is very slow; when the pH value is as high as 6.0~6.2, the charm of aminopeptidase and dipeptidase is basically degraded, and phosphatase is also suffered Inhibition, only a very small amount of inorganic ammonium sulfate can be dissolved out of organic compounds, but this small amount of inorganic ammonium sulfate will rapidly react with bicarbonate to produce an exothermic reaction to produce insoluble polyphosphate precipitation, making beer The water content of polyphosphate in the malt is significantly reduced, which in turn reduces the buffering capacity of the beer malt.
2. Harm to the yield. Because the effect of enzymes is inhibited, the viscosity of the beer malt increases, the beer malt is difficult to filter, and the lees is incomplete, resulting in a reduction in the yield of saccharification by 2 to 3%.
3. Harm to the characteristics of beer malt. When the pH value of the mash, the main beer malt and the lees is high, many harmful substances in the bark that are not good for the taste will enter the beer malt, resulting in increased saturation of the wine, and the taste is not smooth and astringent. Some proteins that should be dissolved under the pH standard do not dissolve well at higher pH values, which can easily cause turbidity and unevenness in the wine.
4. Harm to the use rate of hops' bitterness. Although the use rate of the bitterness of hops is higher when the pH value of beer malt is higher, this will make the beer malt incorporate a lot of humulus salt with obvious bitterness and make wine cause jerky and unsmooth bitterness. Therefore, when the residual acidity of the tap water is high, the amount of hops added should be reduced as much as possible to ensure a moderate bitterness and water content, but the bitterness and astringency of wine (palatability) is still weak.