Seed cleaner

One of the big issues with small scale grain and seed growing, I have found, is cleaning the result. I have grown sesame seed which sat around for a year because it had too much chaff to use, ditto sorghum. Dried beans, I shell be hand to avoid chaff bits, and it takes forever, especially with small one.
 Recently, I have joined the Ujamaa seed cooperative, and they needed a way to clean seeds coming in from the growers. As a member with a garage full of woodworking tools, I ended up with the task of making a seed cleaner. It worked out well, I have to say - no super high throughput and needs electricity to run, but it works and was, overall, pretty easy to build.
 I started from these plans: https://www.realseeds.co.uk/seedcleaner.html
I was thrilled to find them, but the issue with them as written was that cleaning the machine would be hard. So, I included some of the modifications shown here: http://www.bcseedtrials.ca/2019/01/02/building-a-zig-zag-seed-cleaner/

I did NOT change the size from the original realseed plans: for a first pass, I wanted the tried and true dimensions, especially because I wasn't sure what type of vacuum we’d end up with. But I did make the front into a door on hinges, closed with chest clamps. I also used the rubber type window gasket rather than the foam - it made it trickier, but felt less toxic, somehow.
Next up: tips for building.

Hi Lina,
Ujamaa is amazing! Heard some of their members speak at different conferences. That's a really neat seed cleaner. Have you tested yet?

we grow a small amount of seeds for Sow True in Asheville. We just joined a WNC seed collective too.  Anyways they are building a winnow wizard for their cleaning of seeds. I've seen the one you've built before. Is there a reason you selected this model?  I'm just curious, we use screens and it's many hours of labor.

here's the winnow wizard

http://luterra.com/winnow-wizard/#:~:text=As%20a%20precision%20density%20separator,is%20an%20open%20source%20design.

Thanks Sena! Ujamaa is indeed amazing, it is a privilege to work with them.
To be frank, I chose the vacuum model because it was a) cheap to build, with all parts easily available at the hardware store, b) fairly easy and forgiving of less than meticulous woodworking skills, and c) fairly small and easy to store: space is at a premium at the Ujamaa location, and my garage aint that big either!
  I have tried it, and it works pretty well. I’ll try to get some video posted.

Ok, so… I am epically bad at taking pictures during a project, so all I have is an end point. But, if you want to build one, here are a few tips:
1) Even if you are building the one from realseeds, the materials list from bcseedtrials is a pretty good match. I ended up with one extra piece of 1x4 - or rather, I would have if I hadn’t needed to recut a piece.
2) if you live in the US - find yourself a tape measure with centimeter marks. I spent a good two hrs converting, measuring, and ending up with stuff that just wasn’t fitting. My hardware store had a keychain tape measure and a yardstick with cm marks. I got both, which was nice.
3) do sketch out the pieces on your plywood back piece first. It helps with figuring out the angles, some of which aren’t marked.
4) the triangular pieces of the zig zag part were a tad challenging. I ended up ripping a 2x4 with the table saw at a 45 degree angle to get the right sized pieces. The 2x4 was not on the materials list, but I had a short piece sitting around, so didn’t have to buy it.
5) get the vacuum cleaner you want to use first. I think an adjustible speed canister vacuum is the best, but a decent shop vac works too - most vacuums probably will. The thing is, you need a hole saw to cut a hole that will fit the end of your vacuum hose snugly. A shop vac hose might be too large to comfortably fit, in which case you may need an adapter, which is cheap. In any case, measuring the size of your hose and getting a hole saw of that size when you get your supplies will save aggravation at the end.
6) The plexiglass front is not strictly necessary, but it is fun! You could replace it with 1/4 plywood.
7) use lots of glue. Use it like caulk on all the seams so that you have airtight seals.

After I built it, I heard that some people have had issues. I am not sure why, but my guess is that it can be tricky to get a airtight seal everywhere. I got around this by using wood glue on every seam like caulk, and by making the little door on the bottom right close with chest clamps and window the rubber window flashing. The original just had a tight fit on the wood. At some point, I might modify so that is is hinged, which would make it slightly easier to operate. Also, don skip the step where you weight the door while putting on the hinges and chest clamps. That makes certain you have a tight seal on the rubber gaskets.
In order to make it stand straight, I also used a small piece of 1x4 near the center, to make up for the bottom right door clamping onto the bottom.

Here is the finished product. The hole drilled into the front of the plexiglass is to give more control over the suction. I cover it with tape when cleaning larger seeds that need more suction.

I just uploaded a video of it working on my sesame seeds:


Last note: the smaller the hole you pour your seeds in, the stronger your suction will be - but larger seed still need to go through. Best to find a funnel with a reasonable mouth and size the hole to that.

That's awesome Lina!!
Thanks for sharing. This will be quite helpful to many people.

Trying to clean the seeds is the largest stumbling block to saving my own seed. I've been doing it all by hand and, oh my gosh, what a total pain. The larger seeds like beans are not horrible, but radishes? cabbages? Wow. It's rare when I can't come up with something else that needs to be done instead. It's amazing how productive you can be when you're avoiding a task you don't want to do.

The zig zag seed cleaner looks like a do-able project. Thank you! It would be particularly valuable to a homesteading community that could share its use.

I would be interested (and im sure many other permies as well) in being able to purchase a ready-built unit. I don't have power tools or even a garage at this point but have a test plot out of town I'll be trialing some northern adapted sorghum, cowpeas, beans and amaranth and something like this would save me... an extremely large amount of labour in seed cleaning.

A small note as well: a ball valve (probably the plastic plumbing ones) valve mounted into the suction side would be an excellent way to precisely regulate suction

Tammy Farraway wrote:Trying to clean the seeds is the largest stumbling block to saving my own seed. I've been doing it all by hand and, oh my gosh, what a total pain. The larger seeds like beans are not horrible, but radishes? cabbages? Wow. It's rare when I can't come up with something else that needs to be done instead. It's amazing how productive you can be when you're avoiding a task you don't want to do.

The zig zag seed cleaner looks like a do-able project. Thank you! It would be particularly valuable to a homesteading community that could share its use.

For radishes and brassicas, the easiest ways I've found are:

Harvest a ton of the pods, put them them in a strong bag, stomp the hell out of them and pour out the seeds.  Probably 2/3rds of the seeds stay with the bulky pods but who cares, you got enough.

Put crushed up pods in the blender and pulse it a bit.  Pour out the seeds.  Some will be broken but you'll still have tons of good seed.

A lot of seed doesn't need to be clean to grow.  Who cares if you have a bit of chaff mixed in with your lettuce or flax seeds?  Who cares if the carrots have their fuzzy jackets on?  Unless you're selling them, that is...

Mike Haasl wrote:
A lot of seed doesn't need to be clean to grow.  Who cares if you have a bit of chaff mixed in with your lettuce or flax seeds?  Who cares if the carrots have their fuzzy jackets on?  Unless you're selling them, that is...

Or eating them! Sesame, mustard, flax, coriander, sorghum, black cumin, fenugreek, basil seed, fennel, anise, oats - all are potentially useful culinary items that are a pain to clean at the small scale. Some sort of streamlining is helpful, whether that is a seed cleaner, a set of sieves, or just a fan…

Very true! When I'm saving seed for planting, I don't mind if it has chaff, but for example, I recently tried to clean some caraway seed for baking, and, ugh! what a headache! I spent and hour or two poking seeds around on white plates and got a couple of tablespoons of clean seed. Winnowing between two pots outdoors didn't help in this case.

For little seeds like lettuce, I use my wild rice winnowing basket/tray.  It looks like this:

People assume you throw the seeds up in the air and let the wind carry the chaff away but that's not how I was taught.  You hold the basket up at an angle (rising away from you) and flick it downward fast (maybe 4-6").  Then lift it back up slower and flick it down fast.  This lets the seeds levitate while staying above the tray.  Air is drawn through the seeds and it puffs the chaff away off the end of the tray.

So winnowing gets the littler debris and dust out.  Shaking the tray around gets the bigger stuff to often pile up along one edge so you can scoop it off with your fingers.

Winnowing is how I do some seeds, I also have sets of the 5 gallon seed screens and another set that fits on one gallon coffee can. I'd like to come up with a simple column compressed air winnower, adjustable compressed air from the bottom, ports that can be opened or closed at different heights where you could adjust a side puff to blow the chaff out. Work your way down the column to where the seeds are and once cleared of chaff open that port and puff the seeds out to collect. The different level ports might even work as a venturi by using the compressed air at 90 degrees to the column sucking up the lighter chaff as you work your way down the column. Something like a hot air popcorn popper thar has an adjustable snorkel.

When I toured Baker Creek Seeds facilities, they were using the same tools that I use to process seeds. Tarps, buckets, sticks, screens, and fans. They were processing million dollar seed crops with the same simple methods that created civilization.

Fancy winnowing equipment doesn't make things easier. In the time it takes to clean the machine, I could have processed several more lots of seed.

Joseph Lofthouse wrote:
Fancy winnowing equipment doesn't make things easier. In the time it takes to clean the machine, I could have processed several more lots of seed.

Naturally, seed and grain can be cleaned with very little equipment. However, the cleaner I built can be cleaned in less than 2 minutes: you open the door, use the vacuum to suck up any bits of chaff,  then spritz and wipe with rubbing alcohol. I haven’t made a direct comparison, but I think cleaning the bucket, screens and tarp would take about as long, if you were doing the alcohol wipe to avoid disease. If you aren’t, the vacuuming takes less than a minute.
One advantage I see to the cleaner is the compactness during operation. You don’t need a large and preferably outdoor space to spread the tarp, and both the chaff and seed are contained in the machine. You can do it in your house or after dark on a rainy day. Without having dust everywhere.

As above, the space needed for tarp winnowing is a big issue in my situation, plus my climate means that cold snaps to -10° happen by late October, putting me under significant time constraints if I want to winnow anything outdoors. Small footprint of a seed cleaner like above is a very large advantage in my situation. In the future when I have aquired a homestead of sorts and move somewhere warmer, it probably would be a nice device to save time and effort on rainy days, but the tarp method is obviously going to handle larger volumes and not require the electrical input.

Lina, It's kinda hard to see the sesame seeds and to know the path they take. Where do you put the seeds in and where is the suction located? Maybe add a diagram with arrows to show the movement of what is happening? It is a clever build if it works on such small seeds up to larger ones.

Sure! Here is a quick diagram: I think the sites with plans have better ones. Basically, the seeds fall down the narrow side, bouncing off the zig zag pieces. The lighter stuff gets pulled through the narrow opening by the air flow (dashed line) once it gets into the larger chamber, the bulk of it drops down to where you can open the hatche and drop it out at the end.
I like it a lot, but it isn’t a miracle machine. Chaff that is too big and heavy will stay with the seed, just like with any winnowing, so screens to get the really big pieces out are still useful.

Oh, OK, I didn't realize it was a vacuum suction.  So some of the chaff ends up inside the vacuum bag I presume?  I thought it was a blown in airstream, like a strong wind or what I would do with my lungs when I winnow.  When it's a windy day it helps save my breath so I don't get light-headed. I do winnow my birdseed and it can be tricky. I "pour" it slowly from one container to another one held lower while blowing thru the falling seeds.  It goes slowly so I can catch my breath!  Sometimes I use my vacuum cleaner with the hose set into the exhaust to blow at the seeds but it's hard because it really requires a "third hand" for optimal control.  It takes longer or I loose more good seed that way as it (blown air) is so strong.