The goal of rice drying is to reduce its moisture conte […]
The goal of rice drying is to reduce its moisture content to meet the recommended levels for safe, long-term storage. When placed in bins, rice should be dried quickly to a moisture level of about 12% to minimize any quality deterioration. Rice drying can be accomplished in bins by blowing large volumes of dry air through the grain. This website will explore the challenges of rice drying and storage and provide the required spread sheets that might help producers maintain their rice quality and reduce the drying and storage costs.
Tips for Rice Drying:
It is best to place the rice harvested first in the drying bin at a depth of 6 to 12 feet. This depth is dependent on the initial MC of the bulk rice and the capacity of the fans.
Level the rice uniformly across the entire drying bin at the depth selected. It is very important to level the rice in order to distribute the air pressure equally throughout the entire horizontal cross-section of the bin to obtain uniform airflow.
Open the bin exit windows to allow exhaust air to readily exit from the drying bin.
Turn on the fans as soon as the ducts or the perforated floor is covered with approximately 1 foot or more of rice.
If possible, do not hold wet rice in a bin, truck, combine hopper or grain cart longer than 12 hours without moving air through the container to cool the rice.
Measure the relative humidity and temperature of the ambient air to determine the maximum temperature setting of the heater.
It is highly recommended to exercise extreme caution when drying air temperature exceeds 100oF.
Dry high moisture rice in shallow batches until the rice MC is 15% or less. Then, deeper depths with lower airflow requirements are acceptable.
Drying time per batch is determined by airflow rate, measured as cubic feet per minute (CFM) per hundredweight (cwt), temperature difference between air entering and leaving the rice, the MC of the ambient air, and the original MC of the rice.
One way to reduce drying time is to increase airflow, but this may not be the most energy efficient manner of drying.
Once the rice has reached 15% moisture, move it to another bin where the depth can be increased and the airflow per hundredweight (cwt) can be decreased. Drying can be continued until the MC reached 12.5 to 13%. Expect the drying rate of low MC rice to be much slower than high MC rice.