Moisture and Shrink: Why Dry Grain Is Worth More

When you haul a load of grain to an elevator, one of the first numbers on the ticket is moisture. It decides how much the buyer will pay, whether the grain can be stored safely and how much weight disappears when water is removed. A little arithmetic here can save real money.

Why moisture matters

Water in grain has no value to a buyer. Wet grain also spoils more easily, because mold, insects and heat build-up thrive in damp conditions. For these reasons, buyers set a base moisture level for each crop and apply discounts when grain arrives wetter than that level.

Common trading standards in the United States are around 15 percent for shelled corn, 13.5 percent for wheat and 13 percent for soybeans. Local elevators may use slightly different figures, so always check the one on your bid sheet.

What shrink means

Shrink is the loss in weight that happens when water is removed. If you deliver corn at 20 percent moisture and the elevator dries it to 15 percent, the dried corn weighs less than what you brought in. Buyers account for this by applying a shrink factor, usually a percentage per point of moisture removed. A commonly cited figure for corn is a little over 1 percent per point, and many elevators round it up to around 1.2 percent to cover handling losses.

A worked example

Suppose you deliver 1,000 bushels of corn at 20 percent moisture. The base is 15 percent, so 5 points of moisture must come out.

• Shrink: 5 points × 1.2 percent = 6 percent
• Paid bushels: 1,000 × (1 − 0.06) = 940 bushels

On top of that, the elevator may charge a drying fee per bushel for each point removed. If the fee were 4 cents per point per bushel, the charge would be 5 × 0.04 = 20 cents per bushel, or $200 on the original 1,000 bushels. The numbers differ by buyer, but the pattern is the same: wet grain costs you twice, once in lost weight and once in fees.

Safe storage moisture

Storage moisture targets are lower than the base trading moisture, and they depend on how long you plan to hold the grain and the temperature. As a general guide:

• Shelled corn kept until spring is commonly held at about 15 percent or lower, and corn kept through summer is often held drier.
• Soybeans are usually stored at about 13 percent or lower.
• Wheat is often stored at 13 percent or lower.

If you plan to hold grain for a long time, ask your local extension service or agronomist for recommendations for your area.

Practical ways to manage moisture

1. Use a reliable moisture tester and check it against the elevator's meter now and then.
2. Let the crop dry in the field as far as weather allows, since field drying is free while artificial drying uses fuel.
3. Compare drying charges between elevators, as they can differ.
4. Aerate stored grain and check it regularly for hot spots.
5. Remember that a tester reading can vary with grain temperature and sample quality.

Connection to the rest of the chain

Moisture testing is part of the sampling step that happens as soon as a truck arrives. If you want a picture of what happens next, see our walk-through of how a grain elevator works.

Frequently asked questions

Is it always better to deliver grain dry? Usually, since you avoid drying fees and shrink charges. But letting grain dry too long in the field can raise the risk of weather losses, so the best choice depends on the season.

Why does shrink differ between elevators? Because some use only the physical water loss, while others add an allowance for handling and fuel. Ask for the factor in writing.

Can too-dry grain be a problem? Over-dried grain loses weight that you could have sold as water-bearing grain, and some crops can crack more easily when handled, so there is a cost to overdrying.