Question

Why should grains be dried before storage?

Answer 1

Hint: Moisture is the most important factor in the growth of organisms.

Complete answer:
Drying is the oldest and a very common method of storing food, following are the reasons why grains are required to dry before storage:

> Freshly harvested grains are generally dried to about 12% moisture, this makes sure that microbial growth is negligible. Since free water is unavailable, microbes or fungi cannot adhere and grow on the grain, and hence spoiling is prevented.
> Grains themselves require moisture to respire hence preventing ripening.
> When they are devoid of this moisture they enter a state of dormancy and can be stored for extended periods of time due to the fact that during dormancy their metabolic activity decreases.
>To a certain extent, drying prevents insect infesting and destroying of the grains.

Additional information:
Drying methods of grains vary depending upon a number of factors like temperature and humidity of the climate, space available, etc. Common drying methods are listed below:
- In-storage drying methods: in this method grains are dried and stored in the same container
- Low-temperature drying: also known as near-ambient drying. In this system, grains are dried between 30°C to 50°C. It usually takes about 5 days to dry one batch of grains.
Multiple layer drying: this method requires higher temperatures than low-temperature drying. This method is most commonly used to dry corn for storage.
> Batch drying methods:
- Bin batch drying: In this method, a decided amount of grain is placed first which is usually about 2 to 4 inches and the batch is first dried, post drying the batch is cooled and removed.
- Column batch drying: In this method, the grains are placed between two vertical perforated steel sheets where the layer is about 12 inches thick. This method is used when the size of the grains is too small.

Note: Drying in the olden days before technological and scientific advancements were done under the sun. The two major disadvantages of this method were that first, it required grains to spread out over a large surface area, and second, the grains were dried unevenly and were still spoiled comparatively easily.