Reprinted from GRAIN JOURNAL May/June 2020 Issue
This article is based on a presentation by Scott Chant, president, Safe-Grain, Inc./Maxi-Tronic, Inc., Loveland, OH (800-659-8250), given in February 2020 at the GEAPS Great Lakes Regional Conference in Sandusky, OH.
Scott Chant
Grain operations employees have it rough. They’re often the lowest on a company’s food chain, but they’re expected to be alchemists. Merchandisers buy low-quality grain and expect the elevator operator to turn it into gold.
It is the operator’s responsibility to maintain grain quality through a combination of various actions, including segregation, cleaning, drying, aeration, fumigation, and transferring; however, you can’t improve quality. The quality of grain coming into your facility is a good as it will ever be.
Think about buying a loaf of bread at the grocery store. That loaf of bread is as fresh as it will ever be when you take it off the shelf. All you can do is maintain the quality – you can’t improve the quality any more than it is at that moment. And if the bread becomes moldy, can you make it unmoldy and make it tasty to eat again? Of course not. The same principle apply to grain storage.
Moisture migration, mold activity, and insect infestation threaten the quality and condition of stored grain. It is up to the operator to monitor the temperature, odor, and visual appearance of grain to interpret its condition. It also is up to the operator to take prudent steps to keep grain in proper condition, such as aeration, fumigation, and moving/turning the grain.
Shelf Life of Grain
The goal of aeration is to safely change the temperature of the stored product to a level sufficient for safe storage. The amount of time grain can spend in storage before it deteriorates is a function of product temperature and moisture. Insects will become a factor in grain stored at 56 degrees F or warmer. Mold is a possibility wherever there is moisture. To prevent mold growth, keep stored grain at 48 degrees F or cooler.
To determine how long your corn can be stored safely, use the Corn Storage Life Wheel (see Figure 1 at right) by drawing a straight line from your grain temperature to grain moisture. Where the line crosses the middle of the wheel indicates the number of safe storage days. For example, as shown on the chart, corn at 15% moisture and 40 degrees F has a safe storage life of 512 days.
Grain Temperature Monitoring
Once your stored grain is the correct moisture and temperature, you need a monitoring system to keep it that way. The best, fastest, and most reliable way is to use a grain temperature monitoring system. These systems use cables with sensors every 6-8 feet that monitor the air temperature between grains, which is representative of the grain temperature. Because of the voids between grain, the expected temperature coverage range is about 10-12 feet from each sensor. Corn and other large grains in storage are about 2/3 grain and 1/3 air. Smaller grains, such as wheat, are more compact.
When reviewing data taken from grain temperature cables, look for trends – warmer or cooler – that indicate activity in the grain mass. The red cells show a sharp rise in temperature.
The data recorded by the sensors typically is sent to PC-based software. When reviewing the data, focus not necessarily on the temperature, but look for temperature trends. If temperature is changing over time – warmer or cooler – it tells you that something is going on inside the tank (see Figure 2 above).
Tucker Scharfenberg, managing editor
