Grain Mills Q & A
A Technical Discussion About The SAMAP Grain Mill –
From: A Grain of Salt-Fall 1998
The relevance of nutrition to health is now increasingly recognized. For those who are particular about their health, and the quality of the food they eat, freshly milled flour is a must. It is lighter, fluffier and has not time to become oxidized, rancid, or to lose volatile germ oils through evaporation. More and more households are grinding their own grains because of their taste choices, their allergies, their health, or their physician’s orders.
The following is an excerpt from an imaginary interview between the designer of the SAMAP electric and hand mills, Mr. Zimmer, and a potential customer who is interested in the technology of the domestic (household) grain mill.
Q: How fast do the stones of the SAMAP electric grain mill revolve?
A: When the mill is under a full load of grain the speed of the stones is about 2,800 rotations per minute. In terms of the speed at the perimeter of the stones, they revolve at 30 miles per hour.
Q: Is there a noticeable difference in the amount of heat produced when milling finely or coarsely?
A: The difference is significant. The finer the flour, the more energy needed to mill it and the greater the heat thereby generated. The SAMAP mill can produce very fine flour because of its powerful motor and the particular shape and design of the precision-made stones. Our mills can produce a very large portion of fine meal. This is a desirable characteristic because all sorts of cakes, noodles, and other fine things can be made and baked without the addition of any white flour. Also, the bran is almost entirely broken up. The valuable nutritional parts of the grain which normally stay unobtainable between the layers of bran, are thereby made available in the flour. This is just one great advantage the SAMAP mill has to offer over the old mills.
Q: Production of fine flour results in increased mill temperature and increased temperature is not good for grain. What can you say about that?
A: Even the large old stone mills churned out a mill product which was slightly warmer than the temperature of the grain prior to milling. SAMAP has patented a special feature for temperature control. Very fine milling creates a higher temperature in any material. Because of the grain’s fineness, the high temperatures also decrease the flour’s stability. Because of this problem, the SAMAP mill has a very efficient method of cooling. A strong air stream within the mill cools the stones and carries the warmth away from the milling chamber.
Q: What does this cooling system consist of?
A: It consists of two fans that work simultaneously. One fan cools the motor while a second fan, situated under the moving millstones, cools the stoned. The air stream, caused by the fans, cools the stones efficiently and removes the flour from the mill chamber at the same time.
Q: If I have understood you correctly, increasing the amount of grain that goes through the mill must cause even more warmth.
A: Quite right. The greater the quantity of flour milled the more warmth produced in the mill. For this reason, the SAMAP grain mill has an adjustable feed inlet. This inlet allows us to mill corn, dried peas, and several other kinds of large grains at a suitable speed. The adjuster allows a very exact amount of grain to be milled at a certain time. The energy used and the warmth produced can be carefully controlled. This means the mill is never overloaded.
Q: Why does one actually use stones to mill with?
A: Real stones, which have a special structure, have a good effect on the creation of a milled product. Stone is harder than metal and it possesses a valuable resistance to heat. Today, our mills use a magnesite compound, rather than engraved steel, or cast steel, or cut granite. Stone is a poor conductor of warmth in comparison to steel and it actually provides resistance to heat which is optimal to creating quality flour.
Q: Why do you compare stone with steel?
A: Because, in the present day milling industry, mill stones have been replaced by steel rollers. Steel rollers permit very highspeed milling but also create high temperatures.
Q: How would you define “basic quality” when you refer to the stones?
A: The stones of the present grain mills consist of emery and a binding agent in which the emery is set. For our emery, we use only the extremely hard NAXOS granules. NAXOS is a naturally occurring stone that has long been mined for millstones. It is an extremely hard stone, which is beneficial for milling grain. The quality of milled flour is particularly fine when NAXOS stones grind it. The binding agent for these NAXOS emery granules consists of stabilized magnesite cement, which has similar hardness.
Q: How many years life expectancy does a mill stone have with normal family use?
A: An average family uses four to five hundred pounds of wheat in a year. That is assuming that they make all their flour products from the grain they mill themselves. In ten years, they would use two to two and a half tons of wheat. In thirty years, they would use six to seven and a half tons. We have some customers who have used their SAMAP mills very intensively and have already milled more than eight tons of grain without needing to renew the stones. By the way, the stones can easily be changed. All one needs is the right Allan key to slacken a grub screw and the whole mill assembly can be replaced.
Q: From what you have said, can we assume that the SAMAP grain mill will last a generation?
A: I am convinced of it. We already have examples of stones lasting through a generation, even when used very intensively. From the start, we aimed to build a robust, long lasting, trouble-free, and simple machine. We have had good reports from specialists in engineering who say that we have achieved this aim.
Q: Until now we have not mentioned the motor. Presumably that is an important part of the electric mill?
A: We chose a very good motor because, as you suggest its type and construction are relevant, and indeed, crucial to the performance and duration of the mill. Above all, a mill needs a strong, robust motor that is capable of lasting a long time even when it is used a lot. Only an industrial strength motor appears to have these qualities. This strength is reflected in its copper windings, its insulation, and its bearings, as well as in the housing of the motor.
Q: What do you mean by “a good motor”?
A: Above all, a strong, robust motor, that is capable of lasting a long time even when used a lot. Only an industrial motor appears to have these qualities. The robustness and strength of the motor is reflected in all its parts. For example, this is true of the strength of its copper windings, of the insulation, of the cooling in the bearings and in the strength of the housing. Only an industrial motor is satisfactory in my opinion on these accounts.
Q: What sort of motor is in your mill?
A: It is an industrial strength, single-phase motor with a centrifugal switch and a starting capacity of 700 watts. This drives a performance of about 1 h.p. (horse power). The motor of the SAMAP mill is completely dust tight and the cooling air does not force dust into the motor. Our motor housing is fitted with cooling flanges or fins. These armatures produce no sparks and will not cause any interference to radio or television. One of the motor’s important points is that it is quiet even when it is under a full load of grain.
Q: Let’s switch to the hand mill now. There are disadvantages in running a small mill slowly. Does this apply to your hand mill?
A: Yes. With any hand mill there is, however, a pre-condition that the mill must be driven by hand. Human constitution limits the choice.
Q: Please, can we g a bit further into this question of the hand mill?
A: In the hand mill, we have made the diameter of the millstones larger than the stones in the electric mill because the lead in passages, which are needed, cause a reduction in the size of the milling surface. As already pointed out, we have a set limit to the speed possible for turning a mill by hand and a limit imposed by a person’s strength. Thus, we have little room to play with in our calculations. We found it necessary with the hand mill, as with the electric mill, to be able to regulate the amount of grain being fed into the mill. This amount varies according to the strength used and the input of grain desired. Apart from adjusting the distance between the two stones. This limits the fineness of the texture of the flour. In conjunction, these two variables make it possible for people of very different physical strength to use the mill. In order to keep the physical strength required to a minimum, we have built in double roller bearings.
Q: What can the mills not do?
A: It cannot make fine flour out of damp grain. We point this out clearly in the instructions. No one, in fact, can do this, nor can any mill. With the fine setting the stones will become smeared if the grain is too damp. The rule is quiet simple. The finer the flour desired, the drier the grain must be.
Q: Is it difficult or expensive to dry the grain?
A: To dry grain is quiet simple. No extra equipment or handling is required. You should always have a regular supply of grain, preferably in a hesian sac, and you should keep it near, or over, some source of warmth, but not heat. The temperature should not be high, but it will take time to dry it out gently. If you follow this method you will always have a dry supply.
Q: How do I know if the grain is dry or good enough to mill?
A: Feeling it with the hand will tell nothing. It is better to bite a grain or two. If it breaks it is dry. If it squashes it is wet and must be dried further.
Q: Mr. Zimmer, thank you for this enlightened discourse. Now I can see that, when building these grain mills, an incredible number of important things were considered, which an onlooker doesn’t see at all.
A: Well, it was a big step to shift from the idea of wanting to create the ideal household grain mill to arriving at the completed mill. We are delighted. Our customers confirm that the SAMAP mills are technologically sound, fully developed, simple to operate, robust, reliable, and have a powerful performance. Our mills are second to none at producing quality flour.