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Milling or Grinding Grain at Home.

Updated: Nov 5, 2023


A modern electric Burr Stone Mill.


Milling grain at home is not for everyone. The price of a good grain mill is enough to give most of us pause for thought. This article explores the advantages and disadvantages of milling at home along with a brief guide of the mills which are available and which type might suit a home miller best.



Why mill at home?

Grain is magnificently packed nutrition. The seed is viable for up to three or four years. After a couple of years storage grain for home milling is still fresh. It is high in nutrients, trace elements and fresh flavours. Flour bought in the Supermarket is old. A lot of the nutrients in the germ have oxidised and the flavour has diminished.


Modern commodity grains have shallow roots and the minerals in the grain can be as much as a half of those in heritage grain, which have deeper roots.


Heritage flour is often sold at boutique prices whereas buying grain can be a lot cheaper. Heritage and Ancient wheats will always be more expensive than commodity grains and flours as the cropping per hectare is a lot lower.


Bread made from freshly milled flour is more nutritious and it has more flavour.


My electric burr stone mill is over twenty years old and it mills today as well as it did when it was new. I bake two to three times a week and the grain I buy can be as much as ½ the price of the flour. It might be a good exercise to look at grain prices from retailers, or farmers, near you when costing the purchase of a mill.


If you are an occasional baker, or you prefer white breads, then a mill might not be for you. Modern commercial mills do a lot of flour testing and blending to ensure that the flour they sell behaves in a predictable manner. With home milling we have to make small adjustments to our baking to adapt to the flour we have milled.

White flours have little flavour. The exception being white flours from water or wind mills which rub the oily germ into the white endosperm which becomes the white flour.


One of the things that led me to buy a mill was that I used to buy grain by the full sack at a fraction of the cost of the same weight of flour. A sack of grain will easily keep for a couple of years. Now, even though I buy my grain in smaller amounts. It's still cheaper than buying heritage flour.


Heritage and Ancient Grains bought as flour are still nutritious and still give good flavour to the loaf. See the section called Ageing Your Flour.



Commercial Flours

In some countries bleaching flour is still permitted. All manner of chemicals are used for this. It is one more chemical in our diet which we don’t need. After all they only bleach the flour so that we get very white coloured breads. Bleaching oxidises the flour too. That also oxidises the flavour substances, which are mainly carotenoids and so the flour lacks what little flavour it would have had. I say little flavour as nearly all of the flavour in a grain is in the bran and its aleurone layer which is removed when bolting the flour to make a white flour. If you want a flavourful bread 100% Whole Grain a.k.a wholemeal flour can be added to white flour at 20% of the total flour in the recipe. The resulting bread will be light.


Bleaching flours also has the effect of ageing them. Traditionally flours were stored for three to four months so that they oxidised naturally. This oxidisation results in the loss of the carotenoids, but, like bleaching, it toughens the gluten resulting in a better loaf volume. Few flours are going to make it onto the Supermarket shelves in three months. So bleached flour is of little advantage.


Nearly all of the flours on our shop shelves are commodity wheats. In the 1970’s we had what is referred to as the ‘Green Revolution’. Scientists realised that the growth of the world’s population was going to outstrip the amount of wheat that could be grown. They set too breeding the modern commodity wheats which can give yields at up to three times that of an heirloom variety. Unfortunately, a lot of the ‘wheat flavour’ was lost in the breeding process. When I first started baking with heritage wheats I was shocked at how much flavour they had. Again, adding just 20% of a heritage flour to your dough mix will confer a lot of flavour and still gives a light loaf. Heritage wheats develop weaker gluten and so the loaves tend to be heavier. I have written another article on how to get lighter loaves with Heritage and Ancient Grains.


The other thing the home baker needs to keep an eye out for is the addition of Amylase to the flour. I understand this is getting more common with All Purpose Flours. I have come across it in the U.K. with French style Flours. Amylase is added to speed up the fermentation. It also makes the dough slacker (more extensible) and it isn’t so suitable for slower and more flavourful fermentation at home.


Sourcing Grain

It bears saying that before buying a mill it’s wise to see what whole grains can be bought in your part of the globe.

My experience is that there are now an increasing number of farmers growing heritage wheats which are sold on as grain. I am lucky in that there are a number of small water mills within driving distance of where I live. They are all happy to sell bags of grain. Online shopping for grain is the route most of us take.

One of my great delights used to be the smell of freshly milled grain at the mill. I now have that smell in my kitchen when milling and in a way it connects me to the eon old practice of home milling and bread baking.


Milling

Millers go to college for quite some time to learn the craft and science of grain cleaning, milling and bolting. Fortunately, we don’t need quite so much knowledge as we can vary our baking to accommodate the differences of one flour compared to another. A little knowledge is useful though.


Threshing and winnowing: Modern combine harvesters thresh and winnow the grain as they harvest. Threshing removes the straw and the outer husk from the grain and winnowing blows that away leaving the grain.


Cleaning: Our grain comes already cleaned. Cleaning is a process of sieving out dirt, stones and wild seeds from the grain. It also involves magnets to remove any stray iron based metals.


Tempering: Our grains are dried to about 12% moisture. At this moisture level and below they will keep for two years or more. If grain gets too moist they start to sprout, or spoil.

Sparging is a very old milling practice of dampening the grain by sprinkling water onto it and then leaving it overnight. This brings the moisture level up to about 15%. With this moisture level the bran becomes soft and it is easier to bolt (sieve) it off to get a white flour after milling. There are home millers who temper their grain, but I don’t see the point. Even without tempering it is easy to bolt grain down to an eighty percent extraction which is almost white. The Extraction Rate is the percentage of the flour left after bolting. An 80% extraction rate is still a ‘brown’ flour. Modern grains have about 20% bran. A white bread flour typically has an extraction rate of 65% - 75%. That means that 25% - 35% is discarded and it’s often sold on as animal feed.


Milling: At its most basic we pour the grain into the mill, set it on its finest setting and collect the flour at the other end. Milling heats the flour. If the flour reaches 48C / 118F then the glutenin in the flour starts to cook. The resulting flour will make poor bread. Some home millers chill their grain in the fridge or freezer before milling. My mill outputs flour at about 28C / 82F so I don’t bother. A good maximum to be on the safe side is about 36C /97F.

Atta flour is deliberately milled at high temperatures to ‘cook’ the protein. This makes the chapatis easy to roll out.


The next consideration with milling is ‘Starch Packet Damage’. The starch particles in grain are trapped in ‘packets’. The Amylase enzymes which convert starch to sugars for the yeast to feed on cannot break into these. So, we need to damage sufficient starch packets to allow the amylase enzymes, in the flour, access to the starch. Modern millers with their roller mills monitor and control the level of starch packed damage. In the U.S. typically millers chose about 10% starch packet damage as the norm. In Europe millers aim for 6% - 8%. Wind and Water Mills typically have about 20% starch packet damage. The only research I have been able to find for home mills was for the Komo Burr Stone Mill which yielded 15% starch packet damage. I think it is fair to assume that all small burr stone mills achieve this satisfactory rate as they all have much the same milling stones. The point here for the home miller is not to put flour through the mill a few times in order to get a finer flour. This will result in too much starch packet damage.


Finer flour gives a better loaf volume. Good home mills produce fairly fine flour, but putting the grain through the mill once on a very coarse setting and then a second time on the finest setting can produce a finer flour. I would recommend that someone milling for the first time tries putting the flour through once on the finest setting and then do another batch using the coarse then fine technique. Feel the coarseness of your flour rubbing it between finger and thumb and see what the loaves from each turn out like. All mills are a little different.


Some home millers suggest putting the flour through twice on the finest setting. Again, I would be concerned about starch packet damage. Though we can’t directly assess starch packet damage we can see if there is too much as we get softer less elastic doughs if there is too much. If the starch packet damage is excessive a gummy bread will result.


Bolting This is easy to do at home and it is very useful. Bolting is merely the process of sieving some of the bran from out from our whole meal / whole grain flour. I have already said that heritage and ancient grain flours develop weaker gluten. One way to get a good loaf is to use some strong commodity white bread flour, with its stronger gluten, to make up for that.

Another thing we can do is to remove some of the bran by bolting the flour. The bran interrupts the gluten network in our dough and this results in poorer gas trapping and so a denser loaf.


Removing some of the bran through sieving will give us a lighter loaf. Passing the flour through a kitchen sieve will remove enough bran for this. I use a drum sieve with a 1mm mesh size which removes about 8%-10% of the flour weight. All of this is bran. I have a 0.5mm sieve too and this removes up to 20% of the flour weight. I seldom use 0.5mm as this removes too much bran and after all the flavour and nutrients are in the bran and the germ. Any bran that is removed can be used for dusting the bread to give a delightful rustic finish to the loaf.

Some home millers make a bran scald using some of the water to be used in the dough. Simply bring the water near to near boiling point and pour it over the bran. This cooks it and softens it. When cool it can be added to the dough. Because it is softened it will do a little less damage to the gluten network.


Ageing your flour

Freshly milled flour makes really nice bread. The germ with all of it’s protein enzymes is still active and they convey a lot of flavour, nutrition and some vibrancy to the loaf. Fermentation often progresses faster than it would with an aged flour too. So those wanting slow fermentation to ‘brew’ more flavour might want to cut the amount of yeast, or leaven a little.


About 5 – 8 hours after milling the flour begins to oxidise. We have lost the advantage of freshly milled flour which makes a lighter loaf and have not yet gained the advantage of aged flour with its oxidised glutenin conferring strength to the dough. If a home milled flour is not used within five hours it needs to be left for five to six weeks to become stable again as an aged flour. For this reason I mill exactly what I need for a bake and use it immediately. Otherwise we might just as well buy heritage flours already milled.


Heritage and Ancient grain flours bought already milled are still very flavourful and make great bread.




A Roman Type hand mill. These were used in cottages throughout Europe for over two thousand years and are still used in some parts of the world today.


Different Kinds of Mill


Hand Mills

These generally clamp to the edge of the work top. They can have composite stone plates or steel plates. Very simply milling with them requires a lot of work. If you are tempted to get one do watch some videos of them being used first. They are a great alternative to intensive gym time. I have used them.

Mills based on the Roman Mill in the picture above are also available. Again, they are hard work and very slow. The flour many of them produce is on the coarse side. From memory using a hand mill to mill 500g of flour would take an hour with frequent rests.


Impact Mills

These have two cylinders one set off centre inside the other. As these rotate they crush the grain as it passes through. I have never used one, but the reports I have seen say they are noisy and the flour is often not so very fine. The high speed milling would sugest to me that they do too much starch packet damage.


Steel Burr Mill

These have two steel plates, or sometimes steel cones one inside the other. I have one of these as a mixer attachment. They are slower than a free standing home mill, but they do a good job of producing flour. They tend to get hot, so care is needed not to overheat the flour. The flat steel plate versions are not so good and are really a legacy technology in my view.


Composite Stone Burr Mill

These electrically driven mills are very efficient. Good examples are the NutriMill*, Komo and Schnitzer. There are many other brands too. Larger versions are often used on Farms producing their own flour for retail. The ‘stones’ are generally a composite of crushed granite, or basalt mixed with an epoxy resin and cast into shape. These stones are no maintenance and last a very long time. My mill is over twenty years old and I cannot detect any wear. Most of them seem to be made in Germany or Austria. This is a good thing, Germany is famous for its high quality electric motors. They come in different sizes the larger ones having larger stones and a higher throughput. This type of mill is my first choice for home milling. The smaller ones can easily manage a kilo of flour at a time in just a few minutes.


* The NutriMill Classic is an impact mill. NutriMill also make a burr stone mill. Care needs to be taken to get the right one if buying this brand.



Mixer attachments

These can have either steel cone burrs or often conical stones. The steel burr ones tend to get warm, but they do not overheat the flour. Their throughput is on the slower side. The ones with conical stones again have a lower throughput than stand alone mills, but they do a good job. Kitchen Aid sell their own (re)branded version which looks very like a German one to me. It should be good. Kenwood have stopped selling their version which was a re-branded German Jupiter steel burr mill. It does a good job, but it is a little slow. Schnitzer make an attachment for the Kenwood Mixers and they are a top of the line company. Mockmill also make third party mill attachments and they too are a premium company.

Really for home baking, a mixer mill attachment milling 500g of grain once or twice a week adequate for the job. Milling a kilo of grain at a time is possibly their limit because they are on the slow side. I used my Jupiter attachment on a Kenwood for many years. It needed the steer burr plates replacing once, and that was not expensive. They just clip into place. Mixer attachment mills have the advantage that they do not use up space on our ever more crowded work tops.



Other types of Machines

Some folk use a food processor to mill grain. My attempts at this with a good quality food processor have been dismal.


I have no experience of milling with powerful high speed blenders such as Nutrimil and Vitamix. If you have one, you could try it. There are a lot of comparative You Tube reviews looking at the different brands. None of the reviews which I have seen have shown any knowledge of milling, on the part of the reviewer, whatsoever. They usually say run it longer to get superfine flour. I would say run it longer and get too much starch packet damage. They would not be my first choice. Milling grain is quite gentle and they appear to be rather violent in their action. Some are better than others at grinding grains to a fine flour.


Additional Comments.

I mill whole grain basmati rice to a coarse flour. It makes a great non stick flour for bannetons as it has no sticky gluten. It also confers a nice nutty finish to the loaf crust when dusted on top.


Coarsely milled Rye Flour is similarly good for bannetons and for dusting the dough as a finish.

Dried beans are both hard and oily. My experience is that they gum up the grinding stones / plates and many small mill manufacturers recommend not to mill them.

Lentils mill perfectly well. I keep some milled for making soups and thickening casseroles. They cook quickly once milled.

Most manufacturers of home mills strongly recommend not attempting to mill dried Corn/Maize. It is exceptionally hard and may break the mill. Check your instruction manual.


Some mills have a flaker function which will produce rolled oats and rye flakes. Oats, more properly called Groats, are pre-cooked (steamed) as they would otherwise become rancid because of their high oil content.

Rye grain is not pre-cooked (Steamed), unlike the rye flakes in the shops. Home made rye flakes need cooking before being used in Muesli. I find 10min – 15 minutes in an oven at 210C / 410F makes lovely toasted Rye Flakes.

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