The humidity inside the grains, in cereals but also in legumes, can become a problem if post-harvest treatments are not carried out to reduce the level of moisture. In fact, a certain water content is always present in the crops at the time of the harvest. The risk, in these cases, is that excess moisture leads to deterioration of the product in a few days from harvest, causing the onset of molds, aflatoxins or leading to premature and unwanted germination of the grain.
To avoid these problems – and consequent economic losses – it is essential to remove moisture from grains. Once the cereal has reached a humidity level of 13% and temperatures around 15 °C, it can be considered safe from the onset of such deterioration phenomena.
How do you remove moisture from grains in the most efficient and beneficial way? In this article, Mecmar talks to you about the importance of the excess moisture removal process, recommending the best methods and solutions for every need.
Why remove the moisture from grains?
After harvesting, each crop has a certain level of humidity: the more mature the crop, the lower the moisture contained in it. In general, the humidity level can vary from 18 to 25%, but there are many factors that affect this percentage (ripening stage, harvesting season, climate, etc).
In any case, the post-harvest water content is always too high to allow immediate storage without risking losses. In fact, humidity can lead to the appearance of molds and fungi, which produce cancer-causing microtoxins for humans and animals. A cereal containing molds is not accepted by the market, so the work of growing the crop would be lost if such elements arise.
In particular, as regards the contamination of cereals, we have three types of microtoxins: aflatoxins, ochratoxins and fusarium-toxins. Among the best known in the sector there are certainly aflatoxins, responsible for a large part of cereal losses globally: developing in cereals, they make the product dangerous for health and they are recognized as carcinogens agents.
Removing moisture from grains eliminates the risk of contamination and the onset of mold and mildew, with a consequent reduction in wasted time and money.
How to remove moisture from grains?
The main ways to reduce the water content inside the grains are essentially two: natural drying carried out thanks to the heat of the sun and artificial drying, carried out with special machinery for the treatment of cereals.
Natural drying is the most traditional method, carried out extensively in the past but still present today, especially in areas where agricultural mechanization is not yet widespread.
This mode consists in distributing the cereal on a cloth, which is then left outdoors to receive the light and sun rays. This type of drying takes a long time – days or even weeks –, does not guarantee optimal drying and involves various risks (the cereal is easily prey to thieves, contaminants, birds, rodents, as well as exposed to atmospheric agents, so it may be that the nearly dried corn is exposed to strong winds or disruptive rains which reduce its quality).
Mechanical forced air drying (artificial), on the other hand, is carried out using drying systems designed to remove moisture from grains safely and very quickly. These systems, commonly known as grain dryers, use the increase in temperature through a flow of hot air which, surrounding the grain, stimulates the process of water diffusion from the inside to the outside of the grain. Once the water has evaporated, the grain reaches an optimal level of humidity.
What is the best solution for you?
Depending on the needs, there are various grain dryers on the market that meet the most varied requests. To understand how to choose the one that best suits your reality, we can certainly proceed to a first, fundamental distinction: mobile grain dryers and tower dryers.
Mobile grain dryers are suitable for those with medium needs, having the advantage of drying even single batches and different crops, without risking to mix them together. In addition, being equipped with wheels, they are easily transportable and therefore also suitable for those who need to move from one place to another to dry various batches of cereal or to offer the drying service moving from company to company.
Tower dryers, on the other hand, are recommended for more structured companies and drying and storage centers: of larger size and capacity, they exploit a continuous cycle operation for a very high daily production (e.g. 200-400 tons / 24h continuously for several weeks), which gives excellent results with any type of cereal and legume.
Among the Mecmar models, we can point out:
- NANO 6/47 T2 mobile grain dryer - One of the most compact in the range, it ensures a minimum footprint and portability that greatly facilitates operations when mobility is required;
- STR 13/119 T mobile grain dryer - Perfect balance between portability and productivity, this Mecmar model is able to dry and cool more than 100 tons of corn per day (from 20 to 15%), remaining quite compact in terms of size;
- RT 150/7 tower dryer - First among the tower models, the RT 150/7 is able to meet high drying requirements without upsetting the company layout, thanks to a relatively small footprint;
- RG 800/22 tower dryer - The king of the Mecmar range, ideal for large centers that can fully exploit its constant operating capacity and enjoy a daily productivity of 1440 tons of dried product from 20 to 15%.
To remove moisture from grains, natural drying is definitely not the best method: too long times, risks of product loss and uneven drying make this process almost counterproductive. Much more advantageous is to use grain dryers – mobile or tower – which allow optimal and rapid drying. The investment required for their purchase is recovered in a short time and guarantees numerous benefits, reducing losses and increasing profits.
For decades Mecmar has been a specialist in the construction of cereal dryers, customized according to the needs of each customer. If you want to know more or have doubts and questions, do not hesitate to contact us: the Mecmar team is at your disposal.