Final Report for FNE11-731
Project Information
I designed and built a small dehuller that has been tested on winter spelt and spring emmer. The design works as intended with a high dehulling percentage and little to no cracked grain. However, the electronics ended up being more involved and over twice as expensive as I originally envisioned.
That said, the dehuller cost about $13,000. It is worthy to note that in addition to the commercial 1/4″ space cloth screen, I had two wire cloth screen sizes custom woven (one for spelt and one for emmer). These screens do a much better job than the 1/4″ space cloth screen. Due to manufacturing set up I had to have 5 of each of these screens made which cost me a total $3,900. These custom screens will be able to dehull 1,000 tons of grain before they are worn out (100 ton per screen).
When I submitted the grant I did not realize how dust sensitive the variable frequency drives were. They have to be enclosed inside of a Nema 4 or 12 electric panel. I also had to install a filtered ventilation system into the panel. My electrical supplier said that the dehuller motors drive needed a dynamic brake which needed its own separate panel with its own filtered ventilation system. Also there are things like an internal fused disconnect that are needed to be compliant with the electrical code.
The manual is too large a document to upload here but may be downloaded from the site
http://weatherburyfarm.com/saregrant.htm
The actual link to the manual is
http://weatherburyfarm.com/Sare%20Spelt%20Dehuller%20Book.pdf
In the construction manual I have a drawing of how the design could be adapted to run off of a tractor’s PTO.
Introduction:
While spelt works well in an organic system, the hull presents a tenacious problem. With the hull on, the bulkiness of the grain doesn’t make it cost effective to ship spelt long distances. Larger processors want to buy entire truckloads of hulled spelt and a small farmer would probably not have the volume of spelt to fill a truckload. The hull on spelt also prevents small farmers from producing their own flour and selling their flour and whole grains locally. Spelt is gaining in popularity and products made from it can be found in most grocery stores. People with wheat allergies often can tolerate spelt and other people feel that they can digest spelt easier than wheat. Unfortunately the small farmer is shut out from this niche market by his inability to remove the hulls. Flour cannot be ground from spelt with the hulls on.
There are commercially available spelt dehullers; however, the cost of them and their ancillary equipment means a farmer would have to raise over 100 acres of spelt a year to justify the purchase.
Dehulling is a three step process. First the grain is passed through the dehuller which separates the grain kernel from the glume or hull. Then the product is aspirated in an air column to remove the free hulls from the grain. Lastly the hulled grains are sorted from the unhulled grain. For the last step either a grain cleaner which separates the grain on size ( the smaller hulled grain is separated from the larger unhulled grain) or a gravity table that separates on density (the heavier hulled grain is separated from the lighter unhulled grain) is used (either alone or in combination). Used grain cleaners and gravity tables are available at affordable prices. About 30 – 60% of the spelt will be dehulled per pass. The spelt that retains its hull is sent back through the dehuller.
The people I talked to used two classes of machines: American built impact dehullers and German built rotary screen dehullers.
The impact dehullers,made by Forsberg and Codema, cost $7,500 and $20,000 respectively and require an additional $35,000 of support equipment. The impact dehullers have a rotor which rotates at a high speed and throws the grains into a metal ring on the periphery of the rotor. The shock of the impact with the ring causes the grain to separate from its hull.
The German units, used by the people I talked to, are made by Horn Anlagenbau and are a complete plant with a dehuller, aspirator and gravity table all in one unit; they cost $45,000.
In 300 miles from my farm, I have been able to find only 4 people who dehull spelt. The closest person with a dehuller is over 100 miles away. When you consider the cost of shipping in addition to the cost of custom dehulling, it makes this option prohibitively expensive for me and many other small farmers like me.
Additionally, people that do custom dehulling often don’t do identity preserved lots for less than truckload quantities. This is very important to the customers buying directly from small farmers as they want to buy a product that the farmer grew and not a mixture of product from several additional unknown farms.
If the small farmer has a dehuller, its use wouldn’t be limited just to spelt. In addition to spelt, the ancient grains of Emmer (also known as Faro) and Einkorn could be dehulled thus offering an additional niche product for the small farmer.
The objective was to build a small spelt dehuller that would allow small farmers to dehull their spelt and emmer. The goal was to create a dehuller that would dehull 30-50% of the grain per pass. The machine would also have a simple aspirator to remove the hulls after the grain and hulls left the dehulling chamber.
Cooperators
Research
I designed the machine in CAD so that other people can use my blueprints to build a machine of their own. I fabricated the machine. I took pictures along the way which are included in my construction manual to help other people while they are building their own machine. I sandblasted, painted and assembled the machine. I ended up doing the control wiring myself as my electrician went AWOL. I tested my machine both with large grained spelt, small grained spelt and emmer. The machine worked as intended.
I tested the machine with a 2,478lb lot of good quality hulled spelt. With the spelt screen the machine was able to take 620lbs of hulled spelt in per hour and discharge 428 lbs per hour of dehulled spelt. The hulling rate with the spelt screen was 91.8%. The yield rate for dehulled grain on this lot of spelt was 66.58% of the starting rate.
At the end of the first test run, I installed the ¼” x ¼” space cloth screen and ran some spelt. This screen had a hulling rate of 86.4%. The hulls that were retained with this screen were larger intact hulls which would be easier to separate out with just a screen cleaner. So this screen might be a better size for a small producer without advanced separation technology. The throughput seemed comparable to the spelt screen. I was going to use this screen on the next lot of spelt that I was going to dehull to get some accurate data on throughput. But, the next lot of spelt was from 2012 when we had a drought and ended up having much smaller grains.
I ended up using the emmer screen to dehull the 2012 spelt. While I didn’t keep accurate track of the time, the throughput on this screen was about 400+ lbs/hr of hulled spelt in and an output of about 300 lbs per hour of dehulled spelt. The power requirement was also higher with this screen.
At the end I ran some spring emmer through the emmer screen and the machine did a nice job dehulling at a work rate comparable to the small spelt. I didn’t do a prolonged test as I don’t have much emmer left beyond what I am saving for seed.
The hulling percentage was much higher than I anticipated. The work rate was a little lower than I thought it would be but the machine did an excellent job with little to no cracked grain.
I was going to sell the first lot that I dehulled to a local mill as milling grade spelt. But, they felt that the quality was as good as or better than the spelt berries they were buying from a large supplier so they will be selling the grain as spelt berries instead.
I created a dehuller, while more expensive than I originally intended, which accomplishes the goal of offering smaller farmers an option to allow them to dehull their spelt and emmer. I have tested this machine with spelt and emmer and it will probably also work to dehull einkorn.
Education & Outreach Activities and Participation Summary
Participation Summary:
I talked about my dehuller as part of the presentation that I gave at the PASA/Penn State field day on June 25, 2013. My dehuller was briefly mentioned in the PCO Matters article in the Fall 2013 newsletter covering the PASA/ Penn State field day. I also talked about my dehuller as part of a producer panel at the Kneading Conference in Skowhegan Maine on July 25, 2013. My dehuller was also mentioned in a Mother Earth News Article in the April/May 2014 Edition. I have also responded to numerous emails about my dehuller. OGRIN as part of its OREI grant is also comparing the economics of my dehuller to other dehulling systems.
Here is the article in Mother Earth News that mentions my dehuller: http://www.motherearthnews.com/real-food/how-to-grow-wheat-zm0z14amzbla.aspx?PageId=4#axzz2xOJ6eCjz The section on hulled wheats starts on page 4 and the article mentions my dehuller on page 5. I have corresponded with a couple of people about my dehuller who had seen it mentioned in this article.
Here is the article in the PCO Organic Matters Newsletter about the Penn State PASA field day where I talked about my dehuller as part of the presentation that I gave: http://np.netpublicator.com/netpublication/n95738459 It briefly touches on that I had built the dehuller on the last column of page 12. (After talking about how spelt, emmer and einkorn need to be dehulled it mentions that I fabricate my own equipment. I talked about the dehuller for 10-15 minutes but it only got a very brief and abstract mention in the article. )
The Construction Manual can be downloaded from a page on our website. I am sending a flash drive with the blueprints to SARE. I will also download the CAD files for people if they send me a flash drive with a return envelope.
The actual link to the manual is
http://weatherburyfarm.com/Sare%20Spelt%20Dehuller%20Book.pdf
In the construction manual I have a drawing of how the design could be adapted to run off of a tractor’s PTO.
Project Outcomes
Potential Contributions
As regional and small scale milling makes a return, there is going to be more and more demand for a way to dehull spelt, emmer and einkorn. This machine offers an affordable small scale solution to the dehulling problem. I have been contacted by numerous people who have expressed interest in my dehuller. While the cost is higher (due to the electronics) than I had anticipated, this machine costs a fraction of the larger scale dehulling machines.
Future Recommendations
There are three steps in dehulling: dehulling (to remove grain from the hull), aspiration (removing the empty hulls from the good grain) and separation (separating the dehulled grain from the grain that still retains part or its entire hull). My dehuller dehulls the grain and aspirates the hulls out.
In the future there should be more research as to the best way to separate the dehulled grain from the grain that still has its hull.
Information Products
- Spelt Dehuller Fabrication Manual (Manual/Guide)
- CAD Drawings (Manual/Guide)
- Spelt Dehuller Plasma Ready Drawings (Manual/Guide)