Three ways producers can better manage stored grain

Invest in monitoring, learn the three basic principles of drying, and clean out those bins before harvest

Reading Time: 5 minutes

When farmers look at their full grain bins they are essentially looking at thousands of dollars in investment.

The last thing any producer wants is to lose any part of that investment before it even leaves the farm, but that’s exactly what happens every year due to overheating and spoilage.

There are three basic things producers need to do to avoid that, said Joy Agnew with the Prairie Agricultural Machinery Institute.

1) Better monitoring

Many producers hold back on buying a monitoring system because of cost and concerns about their effectiveness.

However, costs are coming down, and both efficiency and ease of use are improving, said Agnew.

But the real issue is managing risk, she added.

“Grain conditions can turn quite quickly during storage and if you’re not monitoring carefully, an entire bin can spoil before preventative action can be taken,” she said.

“Look at it this way: If you had a bucket containing a million dollars in cash and it was hanging around in some relatively insecure building on your farm, how often would you go check on it? Probably daily, and you’d probably invest in some kind of monitoring or alarm system to keep you apprised of the condition or status of that bucket of cash. A 100,000 bushels of canola, for example, is worth a million dollars, so it needs to be monitored.

“We never think an entire 100,000-bushel bin can spoil. But it can and it has happened, as recently as last spring in Saskatchewan.”

Agnew sympathizes with producer concerns that many of today’s monitoring systems are not as cost-efficient as they would like.

“The gold standard in grain sensors right now is the strands of sensors suspended inside the bin. They’re great but they only monitor a relatively small portion of the grain itself,” she said.

“Because grain is such a good insulator, if a hot spot exists three feet away from where a sensor is located, the sensor isn’t going to pick up any difference until that hot spot grows and damages more grain.”

However, there are both existing technology and new systems in the pipeline that tackle that issue.

“There’s some well established technology like the OPI grain management system,” said Agnew. “There are some up-and-coming technologies coming out of Winnipeg and Saskatoon that may automate little robots that transport themselves through the grain and transmit data back to a reader.”

One question producers frequently have is whether moisture sensors are better than temperature sensors or vice versa. That depends, said Agnew.

“Some moisture sensors are great if you have tough grain you’re trying to dry using natural air drying (NAD). That’s the best way to determine the degree of drying you’re getting. If the grain comes out of the field relatively dry, temperature sensors are probably all you’re going to need to monitor aeration and storage conditions.”

2) Know these terms: Aeration, NAD and EMC

The terms ‘aeration’ and ‘natural air drying’ are frequently used interchangeably but are actually quite different.

Aeration is used to cool and condition grain throughout the bin while NAD removes moisture. The biggest difference between the two is air flow rate — aeration system have a much lower air flow rate.

“A lot of producers assume that because they have a fan on their bin they can get some drying with that fan. That is not always the case,” said Agnew. “The fan and duct systems have to be selected for NAD if that’s what the farmer wants to do. NAD requires a half to one cubic foot per minute per bushel (cfm/bu) of air flow whereas aeration systems are usually designed for 0.1 cfm/bu — about a tenth of the air flow rate required for drying.”

However, you can get aeration from an NAD fan.

“It’ll just happen faster than with an aeration fan. If you only need aeration, your best bet is to go with a lower cost, smaller fan. If you think you’re going to need both, invest in a larger fan that can achieve the higher air flow rate required for NAD.”

There are several theories out there on what time of day and how long grain should be dried.

Producers need to understand the principle of Equilibrium Moisture Content (EMC), which is basically a measurement of the air’s capacity to dry, said Agnew.

Equilibrium Moisture Content is a measurement of air’s capacity to dry based on outside temperature and relative humidity. Above is a chart indicating the EMC for wheat. If you blow air with a relative humidity of 50 per cent and a temperature of 5 C through wheat, that wheat will eventually equilibrate to 13.1 per cent.
Equilibrium Moisture Content is a measurement of air’s capacity to dry based on outside temperature and relative humidity. Above is a chart indicating the EMC for wheat. If you blow air with a relative humidity of 50 per cent and a temperature of 5 C through wheat, that wheat will eventually equilibrate to 13.1 per cent. photo: PAMI

“EMC helps farmers understand which outside temperatures and outside relative humidity will actually result in drying of the grain,” she said. “It all depends on grain conditions, air conditions, and air flow rate.”

Go to to find EMC charts for a wide variety of grains.

“Producers often get confused because EMC is different depending on the grain,” she said. “The EMC of air at a set temperature and relative humidity is going to be different for wheat than for canola. You have to look at the appropriate chart for the grain you’re drying.”

While the concepts can be challenging to learn, stick with it, she said.

“The more you know, the better it’s going to work for you. A lot of producers say, ‘It doesn’t really matter — we’ll just turn on the fan and let it run.’

“That’s fine, but it’s not going to be as efficient as it could be and it could result in overdrying or maybe not drying at all if you don’t have sufficient air flow rate.”

The problem with turning fans on and off based on EMC is that it requires extensive monitoring and, in many cases, investment in automatic fan control in order to consistently hit the sweet spot.

“It’s very complicated, not well understood and not easy to implement, so honestly my recommendation to producers is to run your fans continuously until you have an automatic fan control,” said Agnew. “The OPI system has a full fan control system available on the market. It’s quite costly and is only really cost effective for very large bins 30,000 bushels and up. Most producers I talk to say they want technology that is suitable for 5,000 to 15,000 bushel bins.”

3) Clean bins between loadings

This is crucial to prevent insect infestations and mould, said Agnew.

“After grain is unloaded and the augers have gotten everything, a person has to go in and sweep up any excess grain that could be stuck or caught along the edge and bottom edge of the bin, around doors and trap doors or anything like that. That’s where old grain can mould, rot, sit and fester or foster microbial or insect infestations.”

But think safety first.

“Do it early in the morning because those bins get really hot once the sun comes up — don’t be going in there when it’s 50 or 60 degrees inside the bin,” said Agnew, adding proper breathing protection is a must.

“There’s dust in there, and there could be fungal spores and mites and things that could irritate the respiratory tract. Be sure to filter those things out by wearing a mask.”

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