Sukup Fastir - Managing Stored Grain

Managing Stored Grain
41
MANAGING STORED GRAIN
I. Basic Principles
Grain will deteriorate faster as temperature and moisture content increase. Using corn as an example, Table 16
illustrates just how quickly grain can spoil even with proper aeration.
Table 16 - Allowable Storage Times for Aerated, Shelled Corn
Corn Moisture
18%
20%
22%
24%
26%
28%
30%
Grain Temp
Days Before Spoilage
ºF
ºC
30
-1
648
321
190
127
94
74
61
35
2
432
214
126
85
62
49
40
40
4
288
142
84
56
41
32
27
45
7
192
95
56
37
27
21
18
50
10
128
63
37
25
18
14
12
55
13
85
42
25
16
12
9
8
60
16
56
28
17
11
8
7
5
65
18
42
21
13
8
6
5
4
70
21
31
16
9
6
5
4
3
75
24
23
12
7
5
4
3
2
80
27
17
9
5
4
3
2
2
Corn is a perishable commodity with a limited shelf life that depends on its moisture content and temperature.
“Shelf life” refers to length of time that aerated, good quality shelled corn can be stored before losing 1/2% of dry
matter. With this amount of dry matter decomposition, it is assumed that corn loses some quality, but maintains its
market grade. For each 10°F (5°C) increase in temperature, storage time is cut in about half when held at a
given moisture content.
Grain moisture content changes with relative humidity of surrounding air. Table 17 shows moisture content of corn
at various temperatures and relative humidity. Contact your local extension office for information on other grains.
Table 17 - Corn Equilibrium Moisture Content
Relative Humidity
10%
20%
30%
40%
50%
60%
70%
80%
90%
Grain Temp
Corn Equilibrium Moisture Content (%)
ºF
ºC
20
-7
9.4
11.1
12.4
13.6
14.8
16.1
17.6
19.4
22.2
25
-4
8.8
10.5
11.9
13.1
14.3
15.6
17.1
19.0
21.8
30
-1
8.3
10.1
11.4
12.7
13.9
15.2
16.7
18.6
21.1
35
2
7.9
9.6
11.0
12.3
13.5
14.8
16.3
18.2
20.8
40
4
7.4
9.2
10.6
11.9
13.1
14.5
16.0
17.9
20.5
45
7
7.1
8.8
10.2
11.5
12.8
14.1
15.7
17.6
20.5
50
10
6.7
8.5
9.9
11.2
12.5
13.8
15.4
17.3
20.2
55
13
6.3
8.2
9.6
10.9
12.2
13.5
15.1
17.0
20.0
60
16
6.0
7.9
9.3
10.6
11.9
13.3
14.8
16.8
19.7
65
18
5.7
7.6
9.0
10.3
11.6
13.0
14.6
16.5
19.5
70
21
5.4
7.3
8.7
10.0
11.4
12.7
14.3
16.3
19.3
75
24
5.1
7.0
8.5
9.8
11.1
12.5
14.1
16.1
19.1
80
27
4.9
6.7
8.2
9.6
10.9
12.3
13.9
15.9
18.9
85
29
4.6
6.5
8.0
9.3
10.7
12.1
13.7
15.7
18.7
90
32
4.4
6.3
7.7
9.1
10.4
11.9
13.5
15.5
18.5
95
35
4.1
6.0
7.5
8.9
10.2
11.7
13.3
15.3
18.4
100
38
3.9
5.8
7.3
8.7
10.0
11.5
13.1
15.1
18.2