Selkirk 4DT was rated for corn stoves. Not sure if it still is. I would not recommend it as the intake air cools the exhaust gas to the point of comdensation and the acids in the exhaust eat holes through the stainless. I used it originally but in 3 months the pipe was rotted out.

Just wanting to say Hi to all the Harman burners out there to get this category started. Hope Thankgiving was good for my american friends.

I have been burning a mix of half barley, quarter rye, quarter lentils and it burns good. The barley alone is very light. Btu/pound means you have to burn a large volume of barley the get the needed heat.
I have a Harman PC 45 which has a stirrer. I didn't care for straight barley or oats due to the light weight.