Grain shrink: what wet grain nets in town, and what dry grain gives away
Sigurd Lindquist, Certified Crop Adviser (CCA), Chetek, Wisconsin
Type your bid, or let the page fill one in.
Enter the moisture and the load.
How your elevator shrinks and charges
| Up to moisture, % | ¢ a wet bushel |
|---|---|
The numbers are on your elevator's discount sheet or the back of the scale ticket. Test weight for bushels: 56 lb.
Per acre
Show the math
How the elevator figures it
The buyer pays for dry bushels at a base moisture. Grain wetter than base gets shrunk on paper to what it would weigh dried to base, and most elevators also take a drying charge per wet bushel. Grain drier than base gets no credit: it is weighed at the standard test weight, so the water you dried off is grain you did not get paid for.
Water shrink is the weight of water taken out, as a share of the wet weight:
water shrink % = 100 x (wet moisture - base) / (100 - base) corn, 25% to 15.5%: 100 x 9.5 / 84.5 = 11.24%Buyers add a little for dry matter lost in handling. Some use a drying table (water shrink plus about 0.5%); others use a flat factor per point, typically 1.2 to 1.5% (NCH-61). A flat factor carries more handling loss the wetter the corn. Iowa State measured 0.22 to 1.71% handling loss on farms and 0.64 to 1.33% at commercial dryers; NCH-61 calls more than 1% a loss greater than those surveys found. The calculator tells you what handling loss your elevator's factor assumes.
Water shrink per point, by base moisture
| Base moisture | Water shrink per point | Used for |
|---|---|---|
| 15.5% | 1.183% | Corn |
| 15% | 1.176% | |
| 14% | 1.163% | Grain sorghum |
| 13.5% | 1.156% | Wheat |
| 13% | 1.149% | Soybeans |
Overdry grain: what it gives away
The dry matter in the grain does not change when it dries. Only the water does. Delivered under base, you are paid on the weight you hauled; at base, the same grain would have weighed more and made more bushels:
bushels at base = bushels delivered x (100 - delivered moisture) / (100 - base) soybeans at 9%, 1,000 bu: 1,000 x 91 / 87 = 1,046 bu, 46 moreSoybeans delivered under 13%
| Delivered at | Share of the crop not paid for | Bushels per 1,000 delivered |
|---|---|---|
| 12% | 1.1% | 11.5 |
| 11% | 2.2% | 23.0 |
| 10% | 3.3% | 34.5 |
| 9% | 4.4% | 46.0 |
| 8% | 5.4% | 57.5 |
The share column is how Nebraska CropWatch states it: of the bushels the crop would have made at 13%, the share that never got paid for. Their example: 75 bushels an acre at 13% harvested at 9% sells 3.3 fewer bushels an acre.
Corn delivered under 15.5%
| Delivered at | Share of the crop not paid for | Bushels per 1,000 delivered |
|---|---|---|
| 15% | 0.6% | 5.9 |
| 14.5% | 1.2% | 11.8 |
| 14% | 1.7% | 17.8 |
| 13.5% | 2.3% | 23.7 |
| 13% | 2.9% | 29.6 |
Questions
How is grain shrink calculated?
Water shrink is 100 times the points removed, divided by 100 minus the base moisture. Drying corn from 25% to 15.5% takes out 9.5 points: 9.5 x 100 / 84.5 = 11.24% of the wet weight. Buyers then add handling loss, either a flat 0.5% on a drying table (11.74% total) or by using a flat factor per point, such as 1.3% a point (12.35% total). That is from NCH-61, the National Corn Handbook shrink publication.
What is a normal shrink factor for corn?
NCH-61 says flat factors typically run 1.2 to 1.5% a point. Water alone is 1.183% a point when the base is 15.5%, so anything over that is handling loss. On 28% corn, a 1.25 factor assumes 0.83% handling loss and a 1.4 factor assumes 2.71%. Iowa State measured 0.22 to 1.71% on farms and 0.64 to 1.33% at commercial dryers; NCH-61 calls more than 1% a bigger loss than those surveys found.
Should I sell wet corn or dry it myself?
Run both. Iowa State's 2019 example: 1,000 wet bushels of 20.5% corn at $3.50, with a 4.8 cent drying charge a point and a 1.4% factor from a 15% base, nets $2,967 sold wet. Dried on the farm at their figured 3 cents a point, with 1% handling loss and $40 of extra hauling, the same corn netted $3,033. Your elevator's numbers and your own drying cost decide it.
How much do overdry soybeans cost?
Beans delivered under 13% are paid on the weight you haul, so the water you dried off is beans you did not sell. At 9%, 1,000 delivered bushels would have been 1046 bushels at 13%, 46 more. Nebraska CropWatch's example: 75 bushels an acre at 13% harvested at 9% sells 3.3 fewer bushels an acre, $33 an acre at $10 beans.
What is the base moisture for corn, soybeans, wheat and sorghum?
Arkansas Extension's FSA1078 lists corn 15.5%, soybeans 13%, wheat 13.5% and grain sorghum 14%. Those are the defaults here. Your elevator's discount sheet is the one that counts, so change the base box to match it.
Is a moisture discount the same as shrink?
Not quite. Some buyers knock a share off the price instead of the bushels: Iowa State's example takes 2% of the price per point over 15%, 11% for 20.5% corn. Paid on wet bushels, that comes to the same dollars as a flat 2% a point shrink with no drying charge, so enter it that way.
Where does the bid come from?
Type your own, or enter your ZIP and the page uses the nearest elevator's posted bid for that grain from the same boards as the cash bids page. With no ZIP, pick a state and the page uses the latest futures settle less that state's median basis, labeled as such. Sorghum has no state basis yet, so it needs your ZIP or your own bid.
Sources
- Hicks and Cloud, University of Minnesota: Calculating Grain Weight Shrinkage in Corn Due to Mechanical Drying, National Corn Handbook NCH-61 (Purdue). Water shrink, drying tables, flat factors, handling loss.
- Iowa State ICM: Grain drying considerations this fall (2019). The 20.5% corn example with a drying charge and a 1.4% factor.
- Hellevang, NDSU: Post harvest tips for later maturing corn (2009). Moisture shrink formula, 1.1834 per point to 15.5%.
- Nebraska CropWatch: Harvest soybeans at 13% moisture. Beans under 13% are paid on weight; the 75 bushel example.
- University of Arkansas: FSA1078. Base moistures: corn 15.5, soybeans 13, wheat 13.5, grain sorghum 14.
Bids: the nearest posted bid comes from the same elevator boards as cash bids near me. The state default is the futures settle less the state's median basis from the basis page. Call the elevator before you count on a bid or a discount.