After all the work you’ve put into growing and harvesting your own wheat, barley, rye, or millet, the last thing you want is rancid or moldy grain, or an infestation of weevils or mice. The best way to store grain in small quantities is in plastic containers in a refrigerator or freezer. However, if you are growing grains on a large scale, you will want to take precautions to properly dry and store your crop. If stored with too much moisture, grains can develop mold growth, toxins, rancidity, and excess heat. Click here for a printable PDF on Using Farm Moisture Testers, courtesy of Iowa State University Extension.
Some of the moisture problems seen in grain can be prevented with careful harvesting– for example, if one part of your field is wetter than another, it should probably be combined at a later date. While it might seem more efficient to harvest the entire field at once, the grain could spoil and be unsafe if not dried properly. (Note: this can be risky, as a damp grain crop can begin to sprout, and will then be of lesser quality for baking. In some cases, you will want to harvest damp grain and make sure it is aerated and dried properly.)
Drying grains thoroughly is essential, and grains should not be harvested and stored until they have an appropriate moisture content. Most grains can be stored with aeration at 19% moisture, or without aeration at 14% moisture, but this varies for each crop. Milling grains should be stored at about 12.5%, soybeans at about 13%. You will want to aerate grains to reduce the moisture of your crop and also to prevent condensation from forming.
When drying grains, the best aeration system is one that uses low temperatures and long drying times to achieve the desired moisture content. Many grain bins have built-in blowers to force air into the grain and continue drying; you can also improvise with fans and blowers. To circulate air through your grain, you can manipulate a perforated drainage pipe so that it covers the top of the grain and around its perimeter, and then connect the pipe to a blower fan with a small motor. Grain-growers and processors recommend aerating grains that are above 14% moisture, but also checking for condensation as temperatures change throughout the storage period.
Click here for information on building and using a Miniature Portable Grain Dryer like the one Jack Lazor at Butterworks Farm uses. This dryer uses a 12″ axial fan and is quite portable. It is very handy for small-scale grain growers to achieve long-term storage of grains!
On-farm storage of grain crops allows growers to send samples to labs or processors before shipping or delivering large quantities of questionable grain. Containers or bins used for grain should be rodent- and insect-proof, and should also be cleaned thoroughly with a vacuum before each season. Keep in mind that if you are recycling containers that have previously been used for another crop or product, your grain can take on that smell and taste. Also note that the temperature in the bin should be similar to the temperature outside the bin to avoid condensation. Keeping grains at low temperatures will minimize insect damage, as insects will not infiltrate grain stored at temperatures below 64°F. Growers in the northeast recommend temperatures between 41°F and 50°F for long-term storage. If temperatures are low and grain is dry, there should be no problems storing grain for long periods of time.