Detailed Explanation of Wheat Summer Storage Methods and Techniques
Due to the characteristics of high temperature and humidity in summer, the storage of wheat in summer is a very troublesome and important issue. So how should we solve these problems? Below we will explain them to you.
Storage Characteristics of Wheat
Strong hygroscopicity: The wheat seed coat is relatively thin, and its tissue structure is loose, giving it a strong moisture-absorbing capacity.
Long after-ripening period: Wheat has a relatively long after-ripening period. Different varieties have different after-ripening periods. Most varieties have after-ripening periods ranging from two weeks to two months. Wheat with suitable moisture content will have improved quality after completing after-ripening, and its storage stability will also be somewhat enhanced.
Relatively tolerant of high temperature: Wheat has strong heat resistance. According to experiments, wheat with 17% moisture can be dried at a temperature not exceeding 46°C; or when the moisture is below 13%, the sun-drying temperature does not exceed 54°C, the enzyme activity will not decrease, and the germination capacity will still be maintained. The processing quality of the milled wheat flour not only does not decrease, but actually improves, and the steamed buns made from it are soft and puffy. This provides a basis for using high-temperature drying or high-temperature insect killing for wheat.
Good storage resistance: The biggest advantage of wheat is its relatively good storage resistance. After completing after-ripening, wheat has weak respiration, lower than that of other cereal grains. Normal wheat with moisture within the standard (12.5%) can generally be stored for 3-5 years at room temperature or 5-8 years at low temperature (15°C), with no obvious change in its edible quality.
Susceptible to insect damage: Wheat is a grain type with poor insect resistance and a relatively high infestation rate. Apart from a few insect species that feed exclusively on legumes, wheat can be infested by almost all stored-grain pests, among which the maize weevil and angoumois grain moth cause the most serious damage. Wheat maturation, harvest, and storage happen to occur in summer, which is precisely the stage of pest reproduction and outbreak. After being stored, the temperature is high, and if rainy weather occurs, it creates conditions very suitable for pest outbreaks.
Wheat Storage Methods
Strictly control moisture: Because wheat has a strong hygroscopic capacity, wheat storage should pay attention to reducing moisture and preventing dampness. Full use should be made of the high-temperature conditions in summer after wheat harvest for sun-drying, so that the moisture content of wheat is controlled below 12.5%, and then it can be stored. After the wheat is stored, moisture-proof measures should be taken, and attention should be paid to the possible moisture stratification and surface caking during the after-ripening period.
Hot storage in sealed bins: Storing wheat hot in sealed bins is a traditional wheat storage method in China. Through sun-drying, the moisture content of wheat can be reduced, and at the same time, during the sun-drying and sealed storage process, the effects of high-temperature insect killing and sterilization can be achieved. For newly harvested wheat, it can promote the completion of after-ripening. Because pests are eliminated, and the moisture content and microbial load of wheat are reduced, the respiration intensity is greatly weakened, allowing the wheat to be stored safely for a long time.
The specific operation method for storing wheat hot in bins is: during the hottest days of summer, choose clear weather with high temperatures, sun-dry the wheat until its temperature reaches about 50°C, maintain the high temperature for 2 hours, and reduce the moisture to below 12.5%. Around 3 p.m., pile it up, store it hot in the bin, and seal the entire bin, keeping the grain temperature at about 46°C for about 10 days, which can kill all pests. After that, the grain temperature gradually decreases and balances with the bin temperature, and then it shifts to normal sealed storage.
In addition, the warehouse, equipment, tools, and utensils used for hot storage in sealed bins all need to be disinsected in advance.
Warm sealed storage: Although wheat can tolerate high temperatures, prolonged storage at high temperatures will also reduce wheat quality. Therefore, after the autumn cool arrives, wheat can be naturally ventilated or mechanically ventilated to fully dissipate heat, and before the warmth of spring arrives, it should be covered and sealed to maintain a low-temperature state. Low-temperature storage is the basic method for long-term safe storage of wheat. Maintaining a certain low temperature in wheat is beneficial for extending seed lifespan and maintaining quality.
Wheat can also be kept under freezing conditions to maintain good quality. For example, dry wheat stored under a low temperature of -5°C is beneficial for enhancing vitality. Therefore, taking advantage of the severe low temperatures in winter, turn the bins, remove impurities, and freeze the wheat, lowering the wheat temperature to about 0°C, and then seal it while cold. This has a good effect on eliminating overwintering pests in the wheat pile. Low-temperature sealed storage can allow long-term storage, but strict precautions must be taken against contact with hot and humid air flows, so as to avoid condensation on the surface layer of the wheat pile.