Post-Harvest Sunflower Drying, Storage Tips
Tuesday, November 15, 2005
filed under: Harvest/Storage
• Consider cleaning sunflower before putting it in storage to help maintain quality.
• Dry sunflower seeds before storage if they’re harvested wetter than 10%.
• 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.
• 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.
• 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.
• Fire hazard can be reduced by turning portable dryers into the wind so airborne fibers are blown away from the dryer intake and by pointing permanent dryers into the prevailing wind.
• Clean the dryer, air ducts and area around the dryer at least daily. Frequently remove the collection of sunflower lint on the dryer column and in the plenum chamber because the material becomes extremely dry and can be ignited during dryer operation.
• 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.
• Fires can be controlled if they are noticed immediately, which makes constant monitoring necessary. Many fires can be extinguished by shutting off the fan to cut off the oxygen. A little water applied directly to the fire at an early stage may extinguish it if shutting off the fan fails to do so. Good idea to keep a fire extinguisher on hand as well.
• 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.
• Run fans and cool sunflower to about 20 to 25 degrees, and then hold them at that point. Safe storage of oil and confection sunflower over the winter is 10% or below.
• Don’t turn fans off too early when drying. Sample the last exit point to make sure moisture has been pulled or pushed through the grain adequately. 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 cooled. A check should include measurements of moisture content and temperature at several locations.
– Ken Hellevang, North Dakota State University extension agricultural engineer