Small Scale Wheat Milling
Small scale wheat flour milling has become a unique and exciting alternative business in the food supply industry and provides an excellent method for those entrepreneurs who want to break away from the current known way of buying flour to bake bread. An essential component of a typical small-scale flour mill is the use of a stone mill which is the main reason why flour from these small mills produces better tasting bread and all sorts of delicatessen. For the business people there is the additional advantage that more bread can be baked out of the same amount of flour due to the higher water absorption capacity of this type of flour. All of this because a stone mill is used in the process to mill the wheat, just like in the old days. However, in South Africa the bread market wants white bread and to produce flour for white bread the bran must be removed from the flour. A roller mill is used to remove the wheat bran and to “pre-mill” the flour and the stone mill will do the finishing touches. Please be aware that in the flour milling industry sometimes wheat flour is bleached but this is not necessary with the typical small-scale flour mills offered by Gertech.
We at Gertech have personally been involved in the development of the small-scale flour milling systems with emphasis on high and consistent quality cake- and white bread flour. Brown bread flour is basically a blend of white bread flour with some of the mill’s by-products mixed back into the flour.
For those of us loving Africa, most equipment is designed and manufactured in South Africa.
The Flour Mill system consists of :
Wheat Intake and Storage
- Choice between a concrete intake pit or a more modest steel hopper.
Grain transport companies do have tipper trucks available which
make the off-loading of the grain a lot easier. From the pit a 6 inch screw conveyor transports the wheat at a rate of +/- 20 to 25 tph to a silo. The picture on the right shows example of storage silos for wheat.
- A wide range of steel silos is available, but for beginners, 2 x 28 ton corrugated bins are sufficient.
- For future use and investment – discussed below – a silo complex of a couple of hundred ton or even more should be planned for.
- From the silos, the wheat gets transported through a very effective aspiration system to remove dust and light impurities preventing dirty grain dust being blown all over the mill.
- The aspirator dumps the wheat into a mechanical tip scale which is used to determine the flow rate. The counter values of the scale are ideal for record holding purposes. Picture on the right shows example of a wheat cleaning system.
- After the scale the wheat goes through a set of shaking screens to remove all remaining under- and oversized impurities.
- The last cleaning machine is the destoner which removes all stones which are similar in size to the wheat kernel.
- After this cleaning process, water is added to the wheat to differentiate the milling characteristics of the endosperm and the bran to allow the bran to be removed during the milling process.
- Flow capacity of the cleaning process is normally between 1,5 to 3 tph.
- A minimum time of 24 hours is required for conditioning, during which the added
moisture penetrates the wheat kernels.Picture on the right shows example of a conditioning bin.
- Gertech provides a 4-compartment square bin matched to the capacity of the mill.
- Where floor space is available, a number of enclosed corrugated bins can also be used for the conditioning process.
- Roller mill with different breaks / stages will remove the bulk of the bran from the wheat. Sieves will separate and divert the flow of the bran away from the wheat endosperm.
- The stone mill is used to finish the flour milling process. The completely different milling action of grinding the partially milled wheat, received from the roller mill, between two stones gives the flour its unique characteristic taste and baking qualities. One advantage of the stone milling process is that the wheat germ is milled by the stones and forms part of the flour and is partly responsible for the better taste. The big industrial mills do not have stone mills due to the relatively low flow rates involved. But the taste of the baked products will make this type of milling system successful.
- This section is normally driven by the market of the mill. Should the flour be soldthrough retail shops the 2,5 kg paper bag is expected to be
popular but 12,5 kg bags and other sizes might be more suitable for the bakeries.
Picture on the right shows example of a Packing machine.
Gertech has first hand knowledge and hands-on experience of operating a typical flour mill and when such a system is purchased from Gertech support to get the system going will be provided. It is not true that “only a button can be pushed” to get a new mill up and running but Gertech will provide all the necessary knowledge-support to equip the new owner / manager of such a mill with enough know-how to get off the ground and produce a good quality flour which the bakery clients will love to work with.
Capacity of the basic single production line installation is around 650 kg of wheat per hour but this changes (not only downwards but also upwards) due to a variety of reasons. Refer to point 4A below to be very careful when discussing mill capacities. Like any type of mechanical equipment, it takes some time (a few months) of dedicated work and fine tuning by the owner / manager to get these practical figures from the mill.
A more advanced version of the mill operates at 800 kg of wheat per hour.
Some main points to be considered before purchasing a complete flour mill:
- The person in charge should be somebody with good practical hands-on mechanical knowledge. A traditionally qualified miller is not necessary the correct person for this job. Any person who can see when a bearing needs to be replaced, or hears when the noise levels start to change and has basic people skills, can make a huge success of these type of mills.
- Get to know a local industrial electrician. Gertech can include the control panel for the equipment but a local electrician is preferred to do the cabling, so when an electrical issue pops up, local support is available.
- The secret of success is keeping daily and accurate production records. Records are the base documents used to manage the mill. These documents will also warn when things turn away from perfect and when equipment needs to be re-adjusted.
- Some basic and simple principles will be taught during the commissioning phase of the mill.
- Extraction (amount of flour extracted from the wheat) is to be chased. Not capacity. This is the principle of the financial success of any wheat mill. During start-up the mill is expected to produce extraction figures of between 68 to 70%. This should slowly be increased to reach values of HLM (hectolitre mass of the wheat) minus 3 %. Extraction figures of 75 % white bread flour is not uncommon and should be expected as a norm. We know millers who understand and apply this principle and have reached figures of HLM minus 2 %.
- Once the extraction principle is under control the miller can slowly try to increase the capacity of wheat flow rate into the mill but this can only be done with the production records in hand as a bench mark.
- The owner / manager of the mill should use a detailed spread sheet to keep track of all costs and income. This spread sheet will explain the extraction-rate-principle (point 4.A above) much better than we will ever be able to explain in a write-up on this web page.
- Quality of the flour is based on the quality of the wheat purchased.
- Quality of the flour is highly dependent on the minimum conditioning time of 24 hrs. Conditioning times of 30 or 36 hrs are even better.
- In purchasing the wheat try to keep consistency. Bakeries prefer to work with consistent good quality flourso it is wise for the miller to focus on consistency as well. Big industrial flour mills do this by blending different grades of wheat. It also important to be aware of the change of wheat over the harvest period when the commercial grain silos get rid of the previous year’s wheat and have more fresh wheat available. Milling fresh wheat only will cause havoc inside the mill and needs to be blended with old, previous year’s wheat. If at all possible, try to invest in a bigger silo to be filled with previous year’s wheat to balance the fresh wheat supply. For consistency the big industrial millers have a range of silos from where the wheat is blended to provide a stable and balanced supply to the mill.
- Make friends with a bakery client who, from time to time can do some test bakes. Some basic knowledge of bread baking will be helpful when clients start to blame the flour. Blame shifting is one of the oldest sins of human-kind and some basic knowledge of the baking process will go a long way in assisting clients solving their problems.
- Make sure some basic knowledge of book-keeping and basic SARS / tax issues are included in the home work package before the mill is started.
- Plan ahead to double the capacity of the mill in the future. This includes an electrical power supply of 250 amps, 400 volt, 3 phase for 2 x milling lines. Motors start-up one by one allowing the start-up current to be kept at minimum.
- Do not underestimate the work and time necessary to make these mills a success. It is our experience that these systems pay for the hard work and long hours required to make the business a success. This is so for any small business and it is not any different for a flour mill.
- There must be a market for the flour. This sounds logic, but without a market there is no reason for the mill to exist.
- There is much more involved in making a business successful. Gertech can be directly contacted for a discussion on this topic which will be based on many years of own experience.
Gertech can be contacted to discuss any specific needs and ideas. Please allow for a couple of days for specified quotations.