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Check Your Oil

Wednesday, November 15, 2006
filed under: Harvest/Storage

Don’t assume that your oil sunflower is destined for crushing, or better suited for the bird seed market. The only way to know for sure is to get a sample tested, before selling on the open market.

“We have so many guys who deliver not knowing their oil, who could have got a better price from the bird seed guys rather than a discount from the oil guys,” says Ron Meyer, Colorado State University extension agronomist. “So it’s always a good idea to test oil content before you bring them in, unless you have them under contract, which then of course you’re obligated.”

Sampling will also establish whether you have oil that’s better than expected, particularly with smaller seed harvested this year, advises John McLean, seed merchandizer with Cargill, West Fargo, N.D.

“Some have been nervous about the oil content of smaller seed. However, while there have been some tough weather areas, we’re seeing some very good oils from smaller seeds, and a lot of that probably has to do with the late frost,” McLean says. A lot of the new crop oil coming in thus far has been high, mid 40s, even some 50% oil on smaller seed, with good test weight. “Know what you have,” he says. “Market on good information, not gut feeling.”

Preserve stored sunflower quality

Run fans and cool sunflower to about 20 to 25 degrees or as near freezing temperatures as possible, and then hold them at that point. Safe storage of oil and confection sunflower over the winter is 10% or below.

Keep in mind that moisture meters will not give accurate readings for seed temperatures below about 40 degrees. To get an accurate reading, place the sunflower sample in a sealed container and allow it to warm to room temperature before taking the measurement. It’s also important to remember to adjust the meter reading for seed temperatures above 40 degrees. The adjustment may be 3 percentage points for sunflowers near 40 degrees. Read and follow the operator’s manual for accurate readings.

As well, sunflower coming from a high-temperature dryer will have a moisture gradient that will generally cause the moisture meter to give a reading lower than the correct value. This causes what is commonly referred to as moisture rebound, so the sunflowers appear to increase in moisture after being placed in storage. To determine the amount of error, measure the sunflower moisture content coming from the dryer, place the sample in a sealed container for at least 12 hours and then recheck the moisture level.

If using a high temperature dryer, always keep in mind that sunflower is an oil-based crop, and fine fibers from sunflower seeds pose a constant fire hazard. Prevent dust and “fines” from accumulating, and keep a fire extinguisher on hand when harvesting and drying sunflower.

Clean the high temperature dryer and area around it clean. Remove sunflower lint that builds on the dryer column and in the plenum chamber frequently, because the material becomes extremely dry and can be ignited during dryer operation.

If using a portable dryer, turn it into the wind if possible so airborne fibers are blown away from the dryer intake.

A major concern is that some sunflower seeds will hang up in the dryer or be stopped by an accumulation of material and become overdried. Make sure the dryer is completely cleaned after each batch, keep sunflower seeds moving and check a continuous-flow dryer regularly (hourly) to see that the sunflower seeds are moving.

Many dryers are designed so that sunflowers can be unloaded rapidly in case of a fire and before the dryer is damaged. In some dryers, only the part of the dryer affected by the fire needs to be unloaded.

Don’t turn fans off too early when natural air or low temperature drying. Sample the last exit point to make sure moisture has been removed from all the grain. If you’re pushing it through from the bottom, then check the grain at the top. If you’re sucking the air from the top, then sample at the bottom of the bin.

Monitor the moisture and temperature of seed in storage. Check the condition of stored grain about every two weeks while grain is cooling, then about monthly after grain has been cooled to winter storage temperature. A check should include measurements of moisture content and temperature at several locations.

Another storage consideration is bin vent icing. There is the potential for bin vent screens to become iced over when operating fans near or below freezing temperatures. There have been a few cases where vents iced over on bins of corn that were being cooled at freezing temperatures, which caused damage to the bin roof. It is recommended to leave a bin fill-hole or manhole unlatched as a pressure relief valve if the air is being pushed up through the grain. If humid air is being pulled in through bin vents at temperatures near freezing, provide an unscreened opening, such as the manhole, for the airflow. However, make sure bin openings are closed for the winter.

– Tracy Sayler, with storage recommendations from Ken Hellevang, North Dakota State University extension agricultural engineer

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