Hydrogen sulfide in beer
Hydrogen sulfide in beer
Formulation of fermentation process specification for home-brewed beer
Formulation of fermentation process specification for home-brewed beer

Beer equipment manufacturers talk about malt quality evaluation

In craft beer, the evaluation of malt quality is believed that many people do not know very well, and do not know how to judge the quality of malt. The beer equipment manufacturer will take you to know about it next.

Quality evaluation and standard of malt

Sensory test

1. Color: Light-colored malt should be light yellow and shiny. Moldy malt is green, black, or red-spotted.

2. Fragrance: The light-colored malt has a malt fragrance, and the dark-colored malt should not only have a malt fragrance but also a burnt fragrance, without peculiar smell.

3. Granular: The wheat kernels are complete and uniform; the wheat has been completely eradicated and the broken kernels are few; no mold, no insects; no impurities.

4. Inclusions: The malt should be removed from the roots and free from weeds, grains, dust, subtilis, half grains, mildew grains and damaged grains.

physical properties
1. Thousand-grain weight: The more completely the malt is dissolved, the lower the thousand-grain weight. Its degree of dissolution can be measured; generally not higher than 30-40 g/thousand grains.
2. Relative density of malt: The relative density of malt is determined by the softness of malt. The smaller the relative density, the better the drying and dissolution of malt. On the contrary, the dissolution is not good. The relative density can be reflected by the sinking and floating test. The sedimentation particle <10% is excellent; 10%-25% is good; 25%-50% is basically satisfactory; >50% is bad.
3. Chemical characteristics: None of the above malt appearance, physical and chemical indicators can make a comprehensive evaluation of the quality of the malt, so the appearance indicators and several physical and chemical indicators should be used to comprehensively evaluate the malt.
Beer equipment manufacturers talk about malt quality evaluation
Influence of main quality indexes of malt on beer quality

1. Moisture

The moisture of the baked malt reflects the degree of dehydration and coking of the malt. The moisture of light-colored malt is controlled at 3.5-5.0%, and the moisture of dark-colored malt is controlled at 2.0-3.0%. During the post-ripening period of storage, the malt requires a rise in moisture (about 0.5-1.0%), so that the husk loses its original brittleness during the post-ripening period, and is broken but not broken when crushed, which is conducive to wort filtration.

2. Saccharification time and α-amylase

The long saccharification time indicates that the amylase activity in the malt is not high. The resulting wort is low in fermentable sugars, resulting in a lower degree of fermentation. The saccharification time was measured according to the reaction of saccharification mash with iodine solution. The activity of α-amylase is related to the following factors: (1) maceration degree (2) germination conditions (ventilation, temperature, time) (3) addition of gibberellic acid

3. Wort turbidity

The agreed wort turbidity can predict to a certain extent the clarity that can be achieved in mashed wort, generally poorly dissolved wort, unclear wort, well-dissolved wort, clear wort. Wort turbidity is affected by barley variety, growing conditions, germination method, drying temperature and malt storage, and cannot be used simply as a quality standard for measuring malt.

4. Chroma Boiling chromaticity correlates relatively well with beer chromaticity. 
The color is deep and the resulting wort is deep in color. The color of the agreed wort does not represent the color of the beer, but can be used to indicate which type of malt it belongs to. The chromaticity is usually proportional to the boiling chromaticity, but it is not always the case. The coking temperature is insufficient, the malt chromaticity is low, but the polyphenol oxidase and peroxidase residues in the malt are too much, and the boiling chromaticity is deep. 
5. The difference between the leaching rate and the coarse and fine powder 
The difference of coarse and fine powder reflects the dissolution of malt cells. It is generally believed that the difference of coarse and fine powder of well-dissolved malt is less than 2.0%. The difference between the leaching rate and the coarse and fine powder is an economic indicator, and the leaching rate is low, which is equivalent to a small amount of beer made per unit of malt, which increases the production cost. The leaching rate of good malt is between 78-82%, and the leaching rate is related to the malt variety, origin, climatic conditions and malting methods. 
6. Protein and library value 
The protein decomposed during the malting process is basically the same as the protein synthesized, so the protein content of malt is similar to that of barley. Generally, oat and oat wheat are lower in protein than added wheat. But the game protein activity is usually higher. The library value is an important indicator to reflect the dissolution of malt protein. The higher the library value, the more complete the protein dissolution, but the excessive protein dissolution will also affect the foam retention and taste of the beer.
Beer equipment manufacturers talk about malt quality evaluation

7. α-Amino nitrogen

An important indicator to measure the breakdown of malt protein. The α-amino nitrogen is low, the yeast is not nutritious, and cannot reproduce normally, resulting in abnormal fermentation and great changes in the taste of beer. Such as yeast taste, diacetyl can not be reduced and so on. The amino nitrogen in wort mainly comes from malt, and only a small part comes from the continued breakdown of malt protein during mashing. For the same variety of malt, amino nitrogen is generally proportional to the stock value. High protein barley is more likely to produce high amino nitrogen levels.

8. Saccharification power

Saccharification power refers to the ability of malt to form reducing sugars under the combined action of α-amylase and β-amylase. Factors affecting the maltose ability: (1) barley variety (2) barley protein content, barley with high protein content has high saccharification ability (3) malting process, which is mainly related to barley soaking degree, malt solubility and drying process.

9. Beta-glucan

β-glucan is an important component of endosperm cell wall, and high temperature germination is conducive to the degradation of β-glucan. The content of β-glucan has a great relationship with the dissolution and variety of malt, and the first decomposition of malt is β-glucan. The viscosity of the aqueous solution of β-glucan is extremely high, and the viscosity gradually decreases with the continuous degradation of its molecular mass. β-glucan is of great significance to beer. Too high content will affect the filtration speed of wort and cause wort to be cloudy, but an appropriate amount of β-glucan is an important substance that constitutes the body and foam properties of beer.

10. Viscosity and Filtration

Time Viscosity reflects the degradation of hemicellulose and malt substances in the cell wall of malt endosperm, indicating the degree of dissolution of malt. For the same variety of malt, the viscosity is high, reflecting the poor dissolution of malt, especially the poor decomposition of protein and β-glucan, high β-glucan content, and long filtration time. Increasing the maceration degree, increasing the germination temperature and prolonging the germination time can reduce the content of β-glucan and the viscosity of the wort.

11. PH value and total acid

The malt with high solubility has a correspondingly higher acidity and a correspondingly lower PH. On the contrary, the malt with low solubility has a correspondingly lower acidity and a higher PH. If the acidity of the malt is not normal, it means that the germination conditions are not normal, such as insufficient ventilation, excessive immersion, excessive germination temperature, excessive dissolution and so on.

The above is Xiaobian’s sharing of malt quality evaluation. If you want to know more about home-brewed beer equipment and other related content, you can leave a message.