Beer brewing water (2)

Influence of Inorganic Ions in Water on Beer Brewing

1. The biggest role of Ca2+ is to adjust the pH value of the mash and wort, protect the activity of α-amylase, precipitate protein and oxalate, and avoid turbidity and gushing in the finished beer; if the content is too high, it will bring rough bitterness.

2. Zn²⁺ is an essential ion for the growth of yeast. When the content is 0.1-0.5 mg/L, it can promote the growth and metabolism of yeast and enhance the foam retention.

3. The carbonate form of Na+ sodium can greatly increase the pH value of mash and wort, and the coexistence of chloride ions can make beer taste salty; too high content often makes beer rough and not soft.

4. SO₄^2- can also increase the pH value of mash and wort; too much will cause bitter taste, which will damage the flavor and foam stability of beer.

SO₄^2- has the effect of increasing acidity, increasing the aroma of hops, promoting protein flocculation, and facilitating the clarification of wort; excessive volatile sulfides in beer will increase, resulting in light and bitter taste of beer.

5. Excessive Fe²⁺ iron content will inhibit the progress of saccharification, deepen the color of wort, affect the growth and fermentation of yeast, accelerate the oxidation of beer, produce rough bitter taste and iron smell, and cause beer turbidity and gushing.

6. A small amount of Mn²⁺ is good for the growth of yeast; excessive amount will make the beer lack luster, rough taste, cause beer turbidity and affect the flavor stability.

7. NO^3- can be used as an indicator ion of water pollution, which can cause serious damage to yeast, inhibit yeast growth, and hinder fermentation.

8. Appropriate Cl^- content can promote the action of α-amylase, increase the activity of yeast, and make the beer taste soft, round and plump; if the content is too high, it will easily cause premature aging of yeast, make beer taste salty, and easily corrode equipment and pipes. road.

9. If the SiO^3- content is too high, the wort will be unclear, which will affect yeast fermentation and beer filtration, easily cause beer turbidity, and make beer taste rough.

Residual Alkalinity of Water and Its Calculation Method

Residual Alkalinity of Water (RA)

The residual alkalinity (RA) of water is an important index to measure the quality of brewing water, and it is also a comprehensive evaluation of the acid-reducing effect and acid-increasing ions in water. Through the calculation of RA value, it is possible to predict the degree of influence of bicarbonate ions in water on wort and beer, so as to find out adjustment and remedial measures to make the whole brewing process go smoothly.

1. Total Alkalinity (GA) of water

When the water does not contain NaHCO3, the bicarbonate in the water mainly combines with calcium and magnesium ions to form corresponding salts. At this time, GA is the carbonate hardness (temporary hardness) of water, expressed in mmol/L. If the water contains NaHCO3, the GA is greater than the carbonate hardness, and the water is negative hardness.

2. Counteracts Alkalinity (AA)

AA is the alkalinity formed by the acid-increasing effect of calcium and magnesium ions counteracting the acid-decreasing effect of bicarbonate.

3. Calculation of residual alkalinity (RA value)

RA＝GA－AA＝GA－(Calcium Hard/3.5 + Magnesium Hard/7.0)

It can be seen from the above formula: when GA is higher than AA, RA is a positive value. The higher the concentration of calcium and magnesium ions, the stronger the acid increasing effect, the lower the RA value, and the lower the pH value of the wort. When AA is higher than GA, the RA value is negative. This kind of situation can only exist when the temporary hardness is much lower than the permanent hardness, and such water quality rarely exists.

4. Requirements for RA value of different beer varieties

 Different beer varieties have different requirements for the RA value of water, and the lighter the color of the wine, the lower the RA value is required.

Pale beer RA≤1.78mmol/L

Dark beer RA＞1.78mmol/L

Black beer RA＞3.57mmol/L

5. Basic requirements for water quality in brewing pale beer

RA≤1.78mmol/L

Total hardness <12.48mmol/L (depending on RA value)

Non-carbonate hardness: carbonate hardness = 2.5~3.0/1

Calcium Hardness: Magnesium Hardness > 3/1

6. Effect of RA value on beer production process

The high RA value of water will increase the pH of mash and wort, which will have a series of effects.

(1) Effects on enzymes The optimum pH value of relevant enzymes in the saccharification process, such as α-amylase, β-amylase, β-glucanase, protease, peptidase, R~enzyme, phosphatase, etc. Both are relatively low, and the pH value is too high, which will inhibit the action of enzymes and fail to achieve the decomposition effect of the corresponding substances, which is unfavorable to the saccharification process, thereby also affecting the fermentation process and beer quality.

(2) Affect the wort yield. Due to the restriction of enzyme action, the decomposition of starch and protein is not complete; the decomposition of β-glucanase is poor, the viscosity of wort is high, the filtration is difficult, and the washing is not clean, so the wort is affected. yield rate.

(3) Influence on the properties of wort The higher the pH value of the wort, the more polymer polyphenols will be extracted from the barley skin, which will make the beer darker, rougher in taste and prone to turbidity.