Proper management of grain production is essential to ensure optimal grain quality and storage. In order to achieve the highest quality and thus the best selling price of grain, it is essential to take care of all stages (sowing, growing, ripening, harvesting, and drying) as well as to know the best processing methods and have the best equipment.
In this article we focus on post-harvest grain drying: the process used to remove excessive moisture from the grain.
Why is it important to dry the wheat after it is harvested?
A moisture level higher than market standards (typically 13%) would lead to the formation of toxins, mold i and, as a result, deterioration of grain quality. Here it is therefore important to understand what drying methods exist.
To date, in principle, we can distinguish between two grain drying methods:
- Traditional method (natural and manual). The grain is spread out in the sun and stirred periodically so that no moisture stratification is created in the thickness. This is a slow process (can take several days), very labor-intensive (requires large spaces) and, often, made inefficient by adverse weather conditions.
- Modern method mechanized through the use of industrialized machinery, with its own loading system and heating zone, which involves precise setting of the internal temperature, which will dry the grain by expelling the excessive moisture contained within it. These methodologies include mobile, tower, continuous-flow, belt, drum dryers and more.
But how best to perform grain drying after its harvest and how to optimize the subsequent storage phase? Continue reading the article to find out with Mecmar experts.
3 reasons why it is important to dry wheat after harvesting
It is necessary to dry grain immediately after its harvest for three different but equally important reasons:
- Storage. Decreasing the moisture content in grain is equivalent to preventing the formation of spoilage microorganisms, which hinder the proper storage of grain, reducing its quality. Some dryers are capable of cleaning the grain as long as it is being dried-the cleaning effect is typically appreciated because it saves the end user from having to purchase a machine dedicated only to this function.
- Loss reduction. Undried grain is more susceptible to attack by mold and bacteria, but not only that. Residual moisture in the grain provides a favorable environment for enzyme activity that can lead to protein and starch degradation in the grain. Drying reduces these risks, limiting losses.
- Nutritional value. The presence of mycotoxins in wet wheat can pose human health risks if the grain is consumed or used in food or feed production. In contrast, dried grain better preserves its nutritional value, ensuring that the final product is of high quality.
Now that we understand the importance of grain drying, let’s see how best to perform it.
In both traditional and modern methods, we distinguish 4 steps in the sequence shown below:
- Loading
- Drying
- Cooling
- Unloading and storage
Depending on the mode and technology, these steps are carried out in series or in parallel on different batches.
Discontinuous-cycle grain drying is certainly the most popular as it caters to a small- and medium-sized farmer market represented by millions of users. Focusing on this technology, initially, the raw grain is loaded inside the dryer via a handling system typically using an auger or elevator (stage 1).
The dryer is then equipped with a system for ventilating, heating and cooling the grain, as well as can be equipped with dedicated devices for measuring grain moisture. The drying phase (phase 2) begins with the gradual lowering of the humidity of the air inside the dryer, thus facilitating the evaporation of the water present in the grain. In order not to expose the grain to too much thermal stress, it is recommended to manage the drying air temperature by setting an increasing value.
Next, we move on to the actual drying phase: the air temperature increases and the flow of heat reaching the grain becomes constant, so as to achieve uniform drying of the grain and thus avoid wet spots. During this phase, moisture is extracted from the grain until it reaches the desired level, which depends on the type and its purpose of use.
During the drying process, it is essential to monitor the air temperature inside the plant, as well as the moisture content of the grain (the goal is to reach a moisture level of 12-14%), on a cadenced basis to avoid overheating or over-drying, which could compromise the quality of the product.
Once the desired moisture level is reached, forced ventilation with hot air is suspended and the grain is exposed to ventilation with air at room temperature. This begins the cooling phase of the grain (phase 3), which is essential to avoid condensation and for the grain to recover shortly the moisture extracted during drying.
This is followed by the unloading of the processed grain (phase 4), typically by elevator or auger, to clear the dryer and leave room for the next batch to be processed.
Would you like to learn more about this topic? You can read the article dedicated to the correct temperature for drying grains recently published in our blog.
Optimizing the wheat storage phase? Here are some tips
Once drying is completed, it is important to pay attention to the storage stage. Properly dried and stored grain has a higher market value. Therefore, it will be easier for you to plan the best time to resell it at the price you feel is most competitive.
But to get the maximum benefits from the storage phase, you need to follow some well-defined guidelines. Here are some tips that come directly from the Mecmar team.
- Check that the silos or warehouses that collect your dried crop are clean, well-ventilated and impervious to moisture, so as to protect the grain from attack by external agents.
- Continue to monitor the moisture level of the grain even during storage and, if necessary, use aeration systems to keep it at the desired level.
- Maintain as constant a temperature as possible inside the silo to prevent grain damage.
- Don’t forget to regularly inspect the stored crop for signs of decay or contamination. By looking at the grain pile from the top of the silo, you can smell the presence of mold or see a change in color tending toward white (signs that the grain is deteriorating and needs to be recirculated or dried again with a dryer).
- Practice crop rotation to avoid accumulation of grain residue or possible infestation by insects or rodents.
In conclusion…
As we have seen, thorough drying of grain after its harvest is essential to preserve its quality, ensure its food safety and maximize its commercial value.
Mecmar, a company that has specialized since birth in the design and construction of dryers suited for all conditions, offers you a wide range of mobile and tower dryers designed to meet the specific needs of modern agriculture.
If you would like to receive more information about our solutions, please do not hesitate to contact us. We are here to answer your questions.
