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Relationship between malt quality and craft beer quality

Sep. 09, 2019

In the actual production process, according to the current experience, the leaching rate, the thickness of the powder, the saccharification time, the filtration time, the color, the total nitrogen, the Coulbach value, the color of the boiled wort, etc. Technical indicators directly affect the quality of beer, we will now describe the quality of malt separately.

1.Leach rate

The rate of malt leaching depends on the variety of the original barley, which is related to the year and location of the planting, and has a certain relationship with the protein content. The high-quality malt leaching rate is usually set at 79.5%~81%. It is very important that the leaching rate is high. If the leaching rate is not measured, no malt analysis is required. Technically, the low leaching rate is often due to insufficient protein solubilization. The protein solubility is higher, the leaching rate is also higher, and the leaching rate does not mean that the carbohydrate dissolves well, so the leaching rate is an important parameter, and it is more important that the cells dissolve well and evenly.

2. Thick and fine powder

The difference in the thickness of the powder indicates the degree of dissolution of the barley cell wall. The small difference in the thickness of the powder indicates that the cell wall is well dissolved, which is beneficial to the filtration and improvement of the mashed wort. The difference in the thickness of the powder affects the utilization rate of the raw material and the filtration speed of the wort and the beer, and also affects the composition of the wort. The difference in the thickness of high-quality malt is less than 1.9%, and the use of malt with low powder and fine powder can increase the yield of beer.

3. Saccharification time

Although saccharification is the result of a combination of alpha and beta amylases, the saccharification time can indirectly show the amount of alpha-amylase present in the malt. If the saccharification time of light malt exceeds 10~15min, saccharification will be difficult. Dissolving malt will prolong the saccharification time. Appropriately increase the degree of impregnation, carry out low temperature germination for a long time, increase the concentration of carbon dioxide in the wheat layer in the late stage of germination, which is conducive to the formation and accumulation of enzymes, and improve the activity of the enzyme to shorten the saccharification time.

4. Chroma

The chromaticity is used as a general indicator in the line standard, and the light color malt requires 2.5~5.7EBC. However, with the popularity of light beer, the importance of the brewery to the color of the malt seems to have become the primary factor of various indicators. Some manufacturers It is required that the lower the malt color is, the better, which is contrary to the objective color and roasting coloration of barley. Other manufacturers think that the malt appearance is bright white and the malt color is shallow. We analyzed the collected samples, some of the malt appearance is bright, but the measured malt color is as high as 9.5EBC. For the color, domestic laboratory testing facilities are different, there are EBC colorimetry, the same malt sample, may be in different laboratories. The following readings are available: 3.0, 3.1, 3.25, 3.3, 3.5 EBC, where 3.0EBC and 3.5EBC may be caused by visual errors, and 3.1, 3.25, 3.3 EBC is the error caused by the estimated reading. In addition, there is an iodine liquid colorimetric method, which has a large operational error and should be eliminated. Therefore, the EBC colorimeter should be used uniformly. The color wheel is regularly calibrated and it is recommended to gradually adopt the EBC digital display meter.

5. Boiling chroma

Boiling color industry standard requires glycerin temperature 108 °C ± 2 °C, according to our test it is difficult to ensure such precision, once the glycerol temperature rises, it takes a long time to fall down, and the glycerol upper and lower layers temperature difference is large, some experiments The room uses saturated brine as a constant temperature water bath. The boiling temperature can reach 108 °C ± 1 °C, and the temperature is consistent at each point. The effect is ok, but the starting temperature should be uniform. The correlation between boil chromaticity and finished beer chromaticity is very good. Therefore, the value of soluble nitrogen is reversely checked. Generally, the light color of the malt boil is up to 7 EBC, and the measured values in different laboratories often vary greatly, indicating that the determination Be very careful and be good. As a general rule, the broth color of different batches of malt cannot be changed too much, otherwise the difference in chromaticity of beer will be too great.

6. Total nitrogen

In order to determine the Coulbach index, it is necessary to know the protein content of malt. The effect of protein content on beer yield is well known. The higher the protein content, the lower the beer yield, but the effect of protein content on beer quality is better than people. The degree of envisioning is much lower. Looking at the protein content alone, the actual range is quite large (10% to 12%) has no effect. It is important to evaluate it with soluble protein.

7. Soluble nitrogen

Soluble nitrogen is an important indicator to measure the degree of protein solubilization. It has a great influence on the quality of wort. It is generally expressed by the Coulbach index and reflects the degree of malt cell wall dissolution to some extent. The soluble nitrogen of malt can neither be too high nor too low, preferably 650~750mg/L. If the value is below this range, the protein solubility of the malt is too low, although this has no effect on fermentation and yeast reproduction, but it will reflect the type of aroma of the beer, such as increasing the ethanol content, but if the soluble nitrogen content is too high There will be no change in the type of aroma, but it will have an impact on the taste of the beer, especially the mellowness of the wine. The use of unmalted cereals to reduce the dissolved protein content gives the beer a "dry" taste. This effect can also be achieved by using malt with low protein solubility, which also makes the beer body lighter. Saccharification has half the effect on protein solubilization, so malt proteins are particularly important.

8. Courba value (index)

The Kulbahar index refers to the ratio of soluble nitrogen to total nitrogen, expressed as a percentage. This index is used to determine protein degradation and allows for a good evaluation of various relationships of proteins while taking into account total protein content. The index is usually set at 38% to 45%. If the total protein deviates from the usual 10% to 11% range, more attention should be paid to soluble nitrogen rather than Coulbach.

9.pH value

The pH indicates the acidity of the malt, and the pH of the malt is usually about 5.90. This value is reduced to 5.75 when heated directly in a furnace with a sulfur-containing material. The low pH makes the activity of most of the enzymes of the glycosylated bismuth increase, so it also has a higher leaching rate and a better value of 45 ° C, but the protein is more soluble. Now the indirect heating method is generally used, and the pH value will be Between 5.85 and 5.90, the pH should be noted: 1 The pH meter should be calibrated before use every day. The temperature difference between the calibration and the temperature at the time of use should not exceed 1 °C. Since many laboratories do not have air conditioning, the temperature difference between winter and summer is large. The pH test has a large error. 2 should be uniformly used to adjust and measure at a constant temperature of 20 ° C, the reported pH should also be specified as the measured value at 20 ° C, no temperature-limited pH value is meaningless.

10. Brittleness

Brittleness reflects the solubility and brewing properties of malt, which is generally required to be above 80% internationally. When measuring in the laboratory, the roller distance and screen should be checked regularly, and the comparison test between the laboratories should be carried out regularly. The malt is stored and transported, the water content is different, and the thickness of the skin is different, which has an impact on the test results. Therefore, the acceptance of commercial malt should be According to the moisture of the variety, the manufacturer's malt brittleness analysis value can be used as the quality proof.

11. Viscosity

The viscosity of wort is related to solubility, and the viscosity value exceeds 1.67 mPa·s, indicating poor cell lysis. A viscosity of less than 1.48 mPa·s indicates that the portion is excessively dissolved.

12.α-Amino Nitrogen

Α-amino nitrogen refers to amino acid low molecular nitrogen, α-amino nitrogen is important for wort composition and beer fermentation, and is the main nitrogen source required for yeast fermentation. The main factors affecting the content of α-amino nitrogen in malt are barley quality and characteristics, wheat immersion, germination temperature and time, temperature and time before drying. If the wheat immersion is low, the temperature in the early stage of germination is too high, the temperature is too low in the later stage, the temperature in the early stage of drying is high, the temperature is too fast, the baking temperature is high, and the time is long, etc., which will reduce the a-amino nitrogen content in the malt.

13. Saccharification

The saccharification industry standard QB-1686-93 puts forward clear requirements for saccharification power and evaluates it as a limited index. The low maltification power is due to the low saccharification power, low protein content, short germination time, low germination temperature and drying temperature of the original barley. High, too fast heating, high baking temperature and long time. The malt saccharification power is too high because of low drying temperature, low coke temperature, short time, and high moisture content. This malt lacks aroma, and the wort is difficult to filter and turbid. Beer is prone to turbid precipitation.


Malt is the main raw material for the production of beer. High quality malt is a material guarantee for the production of high quality beer. How to produce high-quality malt is a topic in front of beer science and technology workers, and it is worthwhile to make unremitting efforts to explore. It is worth our step by step.


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