How cold weather impacts corn oil extraction
As we’re in the midst of the coldest time of the year, it’s important for producers that rely on revenue from corn oil to be reminded of the seasonal oil extraction trends in the industry. Multiple years of data shows that oil extraction tends to decrease with colder weather. The image below shows detectable fat in the corn flour (without regrinding the flour) over the course of 3 years. Note that the fat content dips every January and peaks half way between – during the summer.
The reduction in detectable fat is due at least in part to larger particle sizes in the corn flour – caused by the cold weather. In correlation with the image above, the regression chart below shows an example of the percent of the finest particles from a sieve analysis of corn flour at one plant over the course of nine months for three different screen sizes. It shows that most fines are created in the summer, while significantly fewer fines are produced in winter.
Additionally, the image above shows that as screen size decreased, the percent of fines increased. In other words, more small particles were produced with smaller screen sizes. Just be aware that increased fines can also increase slurry viscosity as they gelatinize quickly. This can also lead to increased suspended solids in the thin stillage and, subsequently, evaporation.
Screen size can help, though. In Novozymes’ trials, plants that switched to smaller screens during colder months mitigated the decrease in fine particles, ultimately helping to minimize the drop in corn oil extraction.
Just as producers take steps to winterize their facilities with an eye to ethanol production, consideration should be given to corn oil extraction.