NCI Future of Feeding Webinar Series | Featuring Dr. Kenneth J. Hellevang

Dr. Kenneth J. Hellevang, Professor and Extension Engineer at North Dakota State University.

Each month, NCI holds a new update in the Future of Feeding webinar series, which focuses on using innovation in the processing of animal food, the equipment being used, as well as using grains from our region for co-products. This last month, we featured speaker Dr. Kenneth J. Hellevang, Professor and Extension Engineer at North Dakota State University. His discussion topic was the proper storage and handling of corn for feed mills.

Hellevang began his presentation by discussing corn conditions as of September 25th, 2022. Corn maturity was, overall, slightly behind where the 5-year average would be. There was also a large degree of variability in terms of planting, drought conditions, etc. across the region. Temperatures in the region are forecasted to be higher than average and precipitation lower than average, though Hellevang stated these would likely begin to shift the other direction around the middle of October.

With the current conditions of the corn crop in mind, Hellevang forecasted that the moisture content of the crop on November 1st, 2022 would likely be between 20-23%. This falls at or above the recommended moisture content for harvesting (20%). It also means that the crop is on track to be harvested in late October or early November, which is right on schedule.

Maximum storage time for corn at varying conditions.

As the graph to the left shows, the maximum allowable storage time for cereal grains varies greatly depending on both the temperature and moisture content of the grains. This range spans from only one day to over 300 days, with much variation in between this range. Though, as Hellevang pointed out, the meters that measure the moisture content of corn aren’t perfect; they’re not accurate below 40 degrees Fahrenheit and are more sensitive to the outside of the kernel than the inside, among other weaknesses. Despite this, they remain an effective tool in gauging this characteristic of corn.

Corn is typically stored in a poly bag, which is a sealed bag that offers protection from the elements. While this bag doesn’t offer protection from mold or insect infestation, it does offer a solution for storing corn. It’s recommended that the bags are ran north-south, so that solar heating is even across both sides of the bag. An elevated location with excellent drainage is also key for preserving the corn for as long as possible. (No matter what, regularly checking and monitoring each bag is key.)

Corn drying time with varying natural air and temperature conditions.

Before the corn is stored, it needs to be dried out. This can be done inside a silo or through natural air drying. For winter storage, the corn is typically cooled to 20 degrees Fahrenheit; from there, drying typically occurs in the spring, once the temp reaches above 40 degrees Fahrenheit. The time required to complete this process is dependent on the time of year and added heat level, as seen in the graph to the right.

The best way to combat corn spoilage from insect spoilage is from cooling which, depending on the degree of cooling, can either reduce insect activity, force them into dormancy, or eliminate them in weeks or hours. (Hellevang was still quick to point out that grain needs to be warm in order to fumigate, which is an important consideration.) This is done by a process called an aeration cycle, which uses the bottom few feet of the grain in the storage bin as a “buffer zone” between the bottom of the bin and the grain being stored for future use.

Risk of ice forming over vents on storage bins.

For optimum operation, Hellevang recommends that the fans in the bins are switched off during rain, snow, and fog. Below-freezing temperatures, on the other hand, pose an entirely different challenge for grain storage: condensation freezing. Condensation from the vents in the storage bin can freeze onto the vent screens and damage the bin due to the pressure buildup from the blocked vents. A solution to combat this issue is to leave the fill and access ports on the bin open to allow for that pressure to escape if the vent screen does freeze.    

To help protect the fans, they should be covered when not in use. This can help keep snow and pests out, and helps prevent warm spring air from entering the bin and interfering with the grain preservation process. It also works to keep damp air out which, once again, could interfere with the process used to preserve the grain.

Something else that’s important to monitor when storing grain is the level of carbon dioxide inside the bin. If the concentration of this gas reaches too high of a level, mold can become a very real threat. As long as the levels remain lower than about 600ppm, the chance of mold growth is minimized. Anything above about 1,500ppm is categorized as a “severe problem” for mold growth.

Three main parts to successfully storing grains.

Really, there are three main parts to successfully storing grains like corn for long periods of time: monitoring, checking, and managing. The first part, like the name suggests, involves monitoring the temperature and moisture content of the grain along with watching for signs of insects and mold. Checking refers to checking the grain every 2 weeks until it’s cooled, every 2-3 weeks during the winter, and back to every 2 weeks during the spring and summer. Managing refers to using measures to adjust the temperature and moisture content along with other factors to minimize the risk of insects intruding on the grain. This can be supplemented with the use of technology, though the human element must still be present.

Northern Crops Institute greatly appreciates Dr. Kenneth J. Hellevang’s involvement and input in our webinar. At NCI, we continue to work towards fulfilling our mission to support regional agriculture and value-added processing by conducting educational and technical programs that expand and maintain domestic and international markets for northern grown crops. All of this wouldn’t be possible without the innovative ideas of guest speakers like Dr. Hellevang.    

To watch the recording, click the video below.    

For more information about future webinars offered at NCI, click here.