Grainstoves from J. A. Mitchell Marketing

Chapter Three: The First Half of the Grain Burning Process

As explained above, the grain-burning process is centered around driving the moisture out of the grain and then heating it to 1100º, so the volatiles can burn. Even though heat is being used to drive the moisture out of the grain, the volatiles will not burn while moisture is coming out of the grain as steam. Instead of burning, the volatiles come out of the grain as smoke. The burning process may therefore be best understood as a process where the moisture is driven out and then the volatiles are burned. Along the way, any efficient and dependable grain-burning stove will have mechanisms to break down husks or hard shells and to deal with the high level of ash produced by the grain combustion.

In the Harmon PC-45, the heat from the fire in the burn pot drives the moisture out of the grain as the grain enters the burn pot from the auger system. In a properly adjusted stove, you will see smoke rising from the first two inches of grain entering the firebox. The smoke is steam mixed with volatiles that are unable to burn because of the moisture. After the grain has moved two inches, all of the moisture should have been removed, and you should see the grain entering the burn pot in a “V” shape with flames burning the grain on the edges of the "V."

Proper V-shape Burn Pattern

The moisture content of the grain is the single most important factor affecting how the grain will burn. If a grain is too moist, the moisture cannot be driven out in the first two inches and the fire cannot be sustained. Many of the problems associated with grain stove operation are the result of an operator trying to burn extremely moist grain. We have found that grain with a moisture content above 14% simply cannot be burned by itself and will have to be mixed with drier or more easily combustible grains. Most of the grain we burn is between 8 and 14% moisture.

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Warning, J.A. Mitchell Marketing Ltd. is not the manufacturer of the Harman PC-45 or any other product. J.A. Mitchell Marketing Ltd. is not responsible for any loss or damage caused by the Harman PC-45 or any other product. J.A. Mitchell Marketing Ltd. provides no representations or warranties. If you are confused or unsure at any point, contact your local Harman dealer.