As promised I will detail a bit more about cleaning popcorn. Usually when I talk to someone about this they wonder if I'm lathering and rinsing the seeds. I am not. The more appropriate name for the process would probably be classifying. Like panning for gold. I only want the gold.
To do this we start with a machine called a screener / scalper. It is commonly referred to as a 'Clipper'. It takes in the shelled popcorn, scalps out the larger debris with the top screen and screens out the smaller debris with the bottom screen. This model is based after an older A.T. Farrell machine called an M2B Clipper. Commodities International in Trilla, Illinois manufactures this replicate. They call it the 'Eliminator 224'.
The Eliminator does a great job getting rid of a whole bunch on unwanted debris and chaff. But it cannot get rid of debris the same size as popcorn like a stone or a pea. Density is not its concern. For that you need a gravity table.
Gravity tables of this small size are not commonly made anymore. This Forsberg #6 gravity table was manufactured in the 1950's in Thief River Falls, MN. It was a bit of a rare find so we jumped at the opportunity to add it to our process. It shakes and blows air through an elevated deck causing the grain to 'float.' The action of the deck causes light objects (cull) to fall downward and the heavier objects to flow up towards the discharge spout. It has many knobs and adjustments and has a pretty steep learning curve to get it to do what you want. But I'm sure by the end of 22,000 lbs of popcorn anyone would feel pretty comfortable.
So now we have ourselves some pretty clean popcorn. The only thing left are seeds and other debris with the same size and density. For now we pick those out by hand. But the ideal next step is something amazing called a 'color sorter.' We might have our eyes on one...you can be sure I'll tell you about it if so.
I'll sign off with a picture of my father's beloved Farmall 560 which ran the hydraulic auger for the entire duration. Thanks!