Chapter 3 Sections

 3.2 Processing Equipment

We detail how we reached the decisions we did when choosing our processing equipment and provide editable basic user instructions to print and display next to each machine. You will need to adapt these to the model that you choose.  We also provide more detailed information taken from the instruction manuals for ongoing maintenance and care of the machines. For details of using the processing equipment See Chapter 6 - Processing the Crops.

3.2.1 How we chose our equipment

When we chose our machinery, we were unaware of any projects operating on the scale we wanted other than John Letts’, when we went to visit his set-up in Oxfordshire we were impressed by the compact size of his machines and their output. He had been using them for a number of years and was clearly happy with what he had. Without other examples for comparison we decided to purchase the same kit(1). Some of John’s equipment came from a manufacturer called Heger in Germany; unfortunately when we approached them they were in the process of selling their business to Horn and so we purchased our polisher (and aspirator) and flaker from them. We purchased our mill from SAMAP in France and our sieve from Farley Green in the UK. Details of the models and their specifications can be found in the table here.

Negotiations with Horn were not particularly easy, partly because of the language barrier; their machines didn’t come with English manuals but we were lucky enough to have a German volunteer who translated the essentials. Farley Green had the benefit of speaking English, but the disadvantage that their sieves are used for a wide range of materials, from paint to pharmaceutical products, and they did not have detailed understanding of the needs of a miller, however John advised us as to what mesh sizes we needed, which was the main consideration. We debated at length getting a second-hand mill that needed refurbishing but decided that this was beyond our skill-set and so stuck with the model that John had. We did buy a second-hand Heger dehuller from Dove’s Farm, only to discover that Horn didn’t make the separator to fit. We enlisted the help of our metal fabricator neighbours to create an adaptor plate so that the two bits of kit were compatible but we never did get the dehuller to operate 100% effectively, and the lack of common language with Horn made trying to resolve this issue extremely difficult.

(1) Thanks to John Lett’s for his generously given advice and time

In this video you can see Holly giving a brief tour of the processing unit and the different processing equipment that we used.

3.2.2 Dehuller

In hindsight we realised that the dehuller wasn’t suitable for use inside the building as essentially it was a ‘dirty’ job and would have been better placed on a farm, working in combination with a winnower (to separate the dehulled crops from the hulled). We struggled to get the dehuller to separate the dehulled from the hulled grains without the winnower and in the end only grew crops that didn’t have a hull, such as peas, naked oats and wheat. In addition to the dehuller, we purchased a separator and a cyclone; the cyclone was necessary to diffuse the energy of the dehuller, simply because we had no way of sending this excess pressurised air outside, as our industrial unit had no walls to the outside accept the front, and blowing out grain waste would have been unacceptable to our neighbours.

The official Heger technical sheet for the dehuller can be found here.

3.2.3 Polisher

All of our grain was sent through the polisher prior to processing. It was an eye-opener to discover just how much dust is removed from the grain.  The polisher was attached to an aspirator that sucked out all of the dust; as the grain travelled the length of the polisher’s brushes the dust would fall through the grid and be sucked out from the chamber below. The polisher was an essential piece of kit for grain hygiene; infestations of mites, moths and their eggs etc are removed by the action of the brushes.

3.2.4 Flaker

The flaker had two adjustable metal rollers; once you’ve got the distance right it literally squashes the whole grain to make a flake, like a jumbo oat. Our flaker had a big magnet which would collect any pieces of metal, picked up in the field during harvest, preventing it from entering the finished product. It would have been better for the polisher to have the magnet, as all of our grain went through the polisher, which would have ensured our crops were uncontaminated by metal, but not all of it went through the flaker. We don’t know if this is an option that Horn offer.

3.2.5 Mill

The mill had a fixed bottom stone. The top stone could be adjusted to increase the gap between the two stones for coarser milling, and could be removed for cleaning. The specific design of the SAMAP reconstituted stone millstones enables the stones to self-sharpen when fine grinding. This ensures constant regeneration of the millstones so they maintain the same bite, supposedly even after numerous years of usage. Natural stone that wears becomes smooth, and this causes the flour to heat up and spoil.   

There was a voltage measure on our mill, showing the maximum voltage that the milling process should reach; anything over this level will cause the flour to get too hot, which is most likely to be caused by having the stones too close together. It also has a counter which records the number of hours the mill has been running, and a timer.

 The SAMAP manual for the mill can be downloaded here.

3.2.6 Sieve

Officially, wholemeal is 100% of the grain with nothing removed. In practice, 99% of millers sieve the flour over a 1.2 or 1.3 sieve to remove husk, bits of straw, insects parts, seed coats of weeds such as vetches, etc. You don't have to do this if the grain is extremely clean, but it usually isn't. Inevitably a small percentage of the largest bran particles are also removed when sieving wholemeal flour. The other advantage to sieving the flour is that it helps to rapidly cool the flour. We sieved all of our flour. For wholemeal we used a coarse sieve, 1.2mm, and for white flour we used 0.6mm.  Note that when comparing sieves the size of hole is not the only factor to consider; you also need to take into account the number of holes per cm2.

The Farley Green Manual for the Sieve S M E-grader can be found here.