How does pulling cores from bins to remove grain fines aid in stored grain health? Well, first let’s look at how we got grain fines in the first place, then how coring grain bins keeps grain healthy.
How Grain Fines Get in Your Bins
Through the grain harvesting process, kernels of the grain can often be broken into smaller pieces. This happens in the grain handling process during harvest. Machinery is the culprit from the field to the bin.
If you also need to dry the grain for storage, now you’ve increased the risk of breakage even more. Overdrying is hard on kernels, and they break even more easily. Plus, you may have had to move them from field to truck to loader to drying bin to storage bin.
That’s a lot of movement and opportunity for breakage.
Now as the grain is placed in the storage bin, the fines tend to end up in the center of the bin. If you don’t remove grain fines, aka broken and damaged grains, you’ll have a storage problem.
Visualize the Inner Workings of a Grain Bin
At this point, the problem may not be clear but just imagine for a minute a tall glass filled with marbles about the same size.
It you poured water into the glass, each space between the marbles would be equally filled, because all the marbles are the same size. This fact makes the space between them also equal in size.
Now, take a similar glass and repeat the process described above except without water. Once you have your marbles in the glass then pour in rice so that it hits the center of the marbles as much as possible. That mimics how grain is loaded into a bin. At this point, you may notice a difference.
The spaces between marbles in the center are smaller compared to those around marbles on the outside of the glass. If you poured water into the glass, you would notice that liquid had a harder time going through the center. On the other hand, the liquid around marbles on the outer edges had no problem.
If you substituted the water for air, you could see that proper ventilation occurs when marbles are equal in size. When you think about a grain bin then, all the grain would be equally cooled. But due to fines, this is not true. In the same way water had a hard time moving through the rice, so does air through grain fines.
What this means for your stored grain is that it is not being cooled uniformly. In turn, you’re increasing your chances of losing money to pests and molds that set up in grain that is too warm.
Pull Cores to Remove Grain Fines
Coring a grain bin simply means you are removing a “core” of grain from the center. If you took a view of a grain bin that is full you will notice that a center peak. This peak is formed as the bin is filled from the top. Drawing the grain down the unloading sump to the unloading auger takes grain from the peak first. If you draw down and unload about half the peak, you’ll end up with a center that’s the same level as grain near the bin wall. Viewed from the top, the surface will now have a W shape.
Think of our glass example. The center is where a lot of the rice was located. In the bin, that’s where a lot of the grain fines are located. When you remove grain fines to the extent possible, it will increase air flow. By increasing air flow you are allowing the grain to cool uniformly.
Coring your grain bin is not 100 percent effective, but at around 90 percent it’s well worth it.
What Size Core Do I Need to Remove Grain Fines?
Since every grain bin is different in size, how much to remove is not cut and dry. Some use a formula to calculate the exact amount that needs to be removed from each bin. But this can be a complicated process.
A simpler approach is to use the golden rule. Remove half the peak to make an inverted cone like the W shape we talked about. This is enough to remove almost all the fines. Those fines that are left will be distributed throughout the grain, which won’t be problematic.
Reflecting on our glass example, let’s just mix a small amount of rice with the marbles. If we put this mixture in the glass and poured water into it, what would happen? The water would move freely compared to the rice all in the core. But, the water will not move as freely as it did with just marbles. No system is perfect.
To pull core from bins to remove grain fines is a simple technique. While it may feel like another farm chore that needs to be done, it will reduce grain profit loss.
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