To ensure a normal saccharification process and obtain a good mashing effect, and to meet the required wort composition for fermentation, each beer brewing process must be designed with reasonable mashing process conditions, that is, the "environmental conditions" controlled by the mashing process. These conditions are as follows:
1. The proportion of malt varieties and different malt varieties used
Different malt varieties or different malting processes of the same variety of barley will result in different malt components. When using different malts in different proportions, consider the needs of the balance process for malt components to achieve fermentation metabolism. As a result, it is reflected in the changes in the amount of flavor substances and the progress of fermentation. Therefore, the process conditions of the mashing process need to be controlled, and the malt varieties and the ratio of varieties need to be selected correctly.
2. The degree of pulverization of raw materials
Different raw materials need to use different pulverization degrees, and different raw materials have different pulverization requirements. Suitable pulverization methods and reasonable pulverization degrees are important conditions for improving the saccharification effect. For example, the roller spacing of the "pair-roll" malt mill is generally controlled to be 0.45~0.55mm, and the roller spacing needs to be adjusted according to the variety of raw materials, water content, and quality of raw materials.
3. The choice of feeding temperature
In order to ensure the freeness, dispersion and function of the enzyme, it is not advisable to use too high saccharification feeding temperature, such as 60°C or even higher temperature. Because the heat resistance of the enzyme, the most suitable temperature and the necessary time must be considered; beer brewing technology usually uses 50°C as a limit for the feeding temperature. When the quality of the raw materials is relatively good, you can use a feeding temperature higher than 50°C, such as 50~55°C; on the contrary, try to use a feeding temperature lower than 50°C.
4. Different mashing stage temperature and action time
The beer mashing process generally uses the method of segmented temperature control to meet the appropriate conditions for the action of different enzymes in the mash process, which is determined by the heat resistance of different enzymes and the most suitable temperature. However, the suitable temperature for enzyme action is not a point, but a range. The more appropriate choice of segmented temperature is to first consider the part of the enzyme action curve that tends to be the most suitable temperature, rather than the temperature range that tends to passivation and inactivation. In addition, the interdependence of enzyme action must be considered, that is, the relationship between the product of an enzyme action and the substrate of another enzyme action must be considered.
5. pH control of mash
Under the condition of ensuring proper alkalinity, it is possible to change the pH of the cold water within a certain range. However, if the pH of the final wort is too high due to the high pH of the hot water, phosphoric acid and lactic acid can be used singly or in combination for proper adjustment.
6. Reasonable mash ion concentration
It is very important to control reasonable water quality and maintain the ratio and stability of the number of ions required in the water quality. The ratio of ions and the number of ions can be different, but they should not change too much, especially pay attention to the important role of Ca2+ and Mg2+ ions in the mash process.
7. Heating method and the level of heat load
The larger the volume of the mash equipment, the greater the degree of influence on the homogeneity and uniform temperature of the material, the heating method (high temperature area), the temperature difference between the heating medium and the material, have a great influence on the mash effect. Therefore, large-volume containers, excessive temperature differences, uneven distribution of heat transfer surfaces, different heat transfer efficiencies at different heating positions, and temperature differences of materials at different cross-sections and different radius positions in the container all have an impact on the mash effect and heat load. The size has a direct impact.
8. Mixing method and mixing time control
The mixing condition has a great influence on the convection, diffusion and uniformity of the material, which is mainly reflected in the direction of the liquid flow, the flow speed and the distribution level. On the premise of ensuring low shear force, a reasonable agitator structure, a reasonable agitator speed and a stirring method are definitely beneficial to the improvement of the mash effect and the improvement of the leaching rate. The stirring effect of the mash process has a greater impact on the dispersion and action of the enzyme, and the leaching of materials.
9. The required first wort concentration and final wort concentration
Mash with a lower original wort concentration is beneficial to improve the mashing effect, and 12oP mash is more advantageous than 15-16oP mash. Therefore, it is more reasonable to increase the concentration of wort in the boiling pot than in the mashing pot. This is related to the effect of enzymes and the theory of feedback inhibition, and is also conducive to improving the adjustment of the material-to-water ratio, the utilization of raw materials, and the utilization of containers.
10. The degree of exposure to oxygen during the mash process
The study found that if 25mg/L of gallic tannin is added to the mash feed water and 10mg/L of gallic tannin is added to the lees water, the mash leaching rate and the filtration performance of the wort can be significantly improved, which means mash a large amount of oxygen exposure in the process has a certain influence on the mash effect and the improvement of the antioxidant performance of the finished beer. This effect may be the oxidative interference of oxygen or free radicals on the action center of the enzyme protein, or the effect of the oxidation of oxygen or free radicals on the enzyme's substrate that affects the action of the enzyme. The effect of adding gallbladder tannins is to improve the antioxidant properties of the mash. Therefore, anaerobic mash is also a very important environmental condition.
This article is excerpted from Xu Bin "Beer Production Questions and Answers"