Getting rocks out of grains

Forgive me if I'm making too hasty an assumption, but I am guessing that investing in a commercial grain-sorter is probably out of the question. Unfortunately that would be just about the only way to guarantee stone-free wheat berries, short of verifying each individual grain by hand. But since, I assume, you want to grind these berries to make bread at some point in the next decade, that doesn't seem like a viable option, either.

But I'm think about the basic principle of grain sorting (le "triage" here in France, a word I love, by-the-bye), and most systems that I have seen are pretty simplistic designs ; on a commercial scale, one will still see the same basic design with some bigger motors attached to handle larger payloads. But the principle is not too complex : passing grain through a series of screens of different textures and sizes to send the bad stuff out at one level and the good at another. Often, even early nineteenth-century "trieurs" were multi-storied screen systems that sifted out different materials at each level (husks, other grains, stones, etc.)

Where the problem comes in, is if your stones are about the same shape and size as your grains. However, if this is not the case, you can go out looking for a wire screen or mesh that seems like it will let wheat pass through (but not rocks). Bring along some samples of your wheat and rocks to do a test on site. I would imagine that your local mom-and-pop hardware store (not your mega-hardware-supply-shops) would be able to help you out finding something like that. If not, then you'll be sure to be bombarded by a barrage of opinions on how to get the job done. (Hence why you go to the mom-and-pop store).

Good luck !

I had this happen with a 40# bag once. Here is what I did.

-Big clean, empty bucket

-Clean table

-Clean newspaper with fold or something that can hold a small pile of grain and fold/lift so the inspected grain can be poured into the bucket.

-the grain

Method:

Take 1-2 cups of grain and pour it onto the newspaper,spreading it into a single layer.

Inspect for debris

Remove debris into garbage

Pick up inspected grain by picking up edges of newspaper,folding and pouring it into clean bucket.

Continue until done.

Really, it only took me about an hour to get it inspected and cleaned and I had a lot of tiny rocks. If you have a lot of sand left, just pour the grain through a flour sifter over a garbage. The sand is small and will fall through the sifter while the grain berries will stay in the sifter.

We are not used to processing our food these days. Imagine harvesting and cleaning it from the stem by beating it on the ground. Then you have the chaff to deal with!

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First, sift the wheat over a sieve or large strainer with 10-12 openings per inch to get rid of the small stuff.  I do that routinely.  If you think you have stones larger than the wheat kernels, sift again through a screen of 6 openings per inch.

After that, you will have to sort by hand, either on a paper as described above, or on a flat-bottomed white plate.  A light-colored formica counter with a square edge might also work. 

A commercial mill uses a de-stoner or gravity table.  I haven't tried it, but you might be able to approximate the process with a large baking sheet.  Put some grain on it and tilt slightly.  Then vibrate the sheet, perhaps with taps from a large spoon.  The denser stones should separate on the high side.