Table of contents


Proper grain storage helps maintain the quality and characteristics the grain possessed immediately after harvesting and drying.

The quality of grain cannot be improved during storage. Grain improperly harvested and dried will remain of low quality no matter how well it is stored.

In cereal grains, loss in quality and quantity during storage is caused by fungi, insects, rodents and mites. Respiration may in certain cases contribute to a loss of dry matter during grain storage. However, the losses due to respiration are minor compared to those caused by living organisms.

This page provides an overview of key grain storage concepts. For detailed information on grain storage, see:

Management of Cereal Grain in Storage

Grain Storage Considerations

Storage of High Moisture Barley

Lentil Storage

Storage time

The storage time of grains varies depending not on the moisture and temperature of the grain:

Canola: if storing longer than 5 months the moisture should be no higher than 8% with uniform temperatures of under 15 °C.

Peas: for prolonged storage the moisture should be less than 14% moisture and be cooled to less than 15 °C.

Cereals: for long-term storage at 14 % the temperature should be 20 °C or less.

Custom rates

According to government surveys, grain drying costs ranged from $45 to 75/hr, or $10 to 12/T, or $0.15-0.24/bu. These costs vary from year to year as energy costs fluctuate. The amount of moisture that needs to be dried out of the grain will also affect the total costs.


The primary purpose for aeration is to achieve or maintain a uniform grain temperature throughout the bin. Some drying can occur in aeration systems, but generally, grain going into aeration bins should be within 1% of being dry enough for long term storage.

Since aeration is a tool for managing grain temperatures, there is no need to turn off the aeration system at night or on cool days, even if it is humid. The benefit of this cool air for lowering the temperature of the grain greatly overshadows any negative effects of the small amount of moisture that is added to the bin.

For more information on aeration, see Management of Cereal Grain in Storage.

Moisture from grasshoppers

Grasshoppers in grain may look and smell like a problem. But it is unlikely that grasshoppers will add enough moisture to a bin to cause grain to go out of condition.

The amount of moisture that grasshoppers add to grain can be estimated based on the average size of grasshoppers and assuming that they are about 70% moisture. The size and weight of grasshoppers varies with species and with gender. Assuming average type weights for the pest species normally found in Alberta, it takes about 300 to 800 grasshoppers per bushel of barley or canola to raise the moisture content of this grain by 1%. In wheat and peas, it takes 400 to 1000 grasshoppers per bushel to change the moisture content by the same 1%.

Seed moisture levels

Table 1. Maximum moisture content levels for straight grade seed*

Seed Maximum moisture content level
Barley (feed) 14.8
Barley (malt) 13.5
Canola 10
Chickpeas 14
Corn 15.5
Domestic Mustard Seed 10
Fababeans 16
Flax 10
Lentils 14
Oats 14
Peas 16
Rye 14
Soybean 14
Triticale 14
Wheat 14.5

*percentage wet weight basis

Grain drying

Costs per bushel for grain drying

Again this is probably best illustrated with an example calculation using several assumptions. Keep in mind that this example includes fuel costs only and does not include the additional costs of labour, electricity, grain handling, depreciation, and other less direct costs.

  • 1 gigajoule (GJ) = 1,000,000 BTU (1 GJ/1,000,000 BTU)
  • Natural gas costs $5/GJ
    • Weight of water to remove: 9.6 lb - 7.1 lb = 2.5 lb/bu
    • 2.5 lb/bu X 2000 BTU/lb = 5000 BTU/bu needed
    • $5/GJ X 1GJ/1,000,000 BTU X 5000 BTU/bu = $0.025/bu

Drying time

Grain drying time depends on the size and efficiency of the dryer, the moisture content of the grain and the volume or weight of grain to be dried. The drying time for grain is probably best illustrated with an example calculation.

  • It takes about 1500 to 2500 BTUs to evaporate 1 lb of water. The manufacturer of the grain dryer should be able to provide these specifications. For this calculation the energy requirement is assumed to be 2000 BTUs/lb.
  • The heating rate in BTU/hr is usually stamped on the dryer or heated aeration unit. For this calculation it is assumed to be 40,000 BTUs/hr
  • The weight of water in barley at different moisture contents is given in Table 2.
  • Assume 2000 bu of barley that is originally at 19% moisture and want to dry it down to 14.8% moisture.

Table 2. Weight of water in barley at various moisture contents

Moisture content % Lbs of water per bushel
25 13.6
22 11.5
20 10.2
19 9.6
18 9.0
17 8.4
16 7.8
14.8 (dry) 7.1
  • Weight of water to remove: 9.6 lb - 7.1 lb = 2.5 lb/bu
  • 2000 bu X 2.5 lb/bu = 5000 lb of water to remove
  • 5000 lb X 2000 BTU/lb = 10 million BTUs needed
  • 10 million BTU / 40,000 BTU/hr = 250 hr = 10.4 days

Maximum drying temperature

The high temperatures in grain dryers can damage the grain. The maximum allowable air temperatures for drying will depend on the crop in question and the end use of that crop (Table 3). Note that the values given in the following table are air temperatures going into the dryer and are not the temperatures of the grain itself.

For more information on grain drying temperature, see Management of Cereal Grain in Storage.

Table 3. Maximum allowable air temperatures for grain drying

Grain Seed Commercial Feed
Wheat 60°C 65°C 80-100°C
Oats 50°C 60°C 80-100°C
Barley 45°C 55°C 80-100°C
Flax 45°C 80°C 80-100°C
Canola 45°C 82°C ---
Peas 40°C --- 45°C