Let’s talk about some of the basics of home milling.
If you are a home baker who regularly uses whole grain flours in your baking, it may be worth considering the purchase of a home mill. As with all things bread, there are many choices and things to consider.
Up front disclaimer – If you regularly use white flours, you will most likely need to continue to purchase them – as it is not really possible to make a white flour with a home mill. White flour is commercially produced by removing the germ and bran from the wheat berry and subsequently milling only the endosperm (starchy portion). The best you can do as a home miller is create a high extraction flour. This is done by sieving (sifting) the milled flour to remove the larger particles. There will still be some bran and germ in the flour and likely some amount of endosperm in the portion sieved out.
The extraction rate, which is simply the weight of the sieved flour vs the original flour weight can be varied by changing either how coarse the flour is milled and/or the size of the sieve used. By sieving, you can achieve a flour that will be lighter than the original whole grain flour.
An example: If you start with 100g of wheat berries – you will produce 100g of whole wheat flour. If you sieve out 15g – you will have created an 85% extraction flour (85g remaining).
85g/100g = 0.85 (85%)
Switching from purchasing flour to buying actual grains may save you (up to ~20%) on flour costs. This will vary greatly based on where you source flours/grains.
How much benefit this provides will depend on how much whole grain flour you regularly use for baking.
If you use 5# of whole grain flour per week – your annual consumption is about 250#. If you are paying around $5 for a 5# bag of flour, your annual expense is $250. Your potential annual savings might be as much as $50. If you use 5# a month, then your potential annual savings might be only $12. You should compare grain and flour costs from your supplier/source.
If you are plan to use more expensive grains (einkorn or emmer, for example), your savings may be greater. It is unlikely that you will elect to buy a mill based solely on cost savings.
The cost savings should be considered when deciding to buy a mill. The prices of mills can become quite expensive and it will be some period of time (often several years) before the cost of the mill is “recovered”. Consider your personal needs when selecting a mill.
There are, however, other benefits of home milling flours – the most prevalent being flour freshness. The germ portion of the wheat berry contains oil which is released into the flour when milled. This introduces the risk of rancidity. Vitamin content will also quickly decrease after milling. One of the most common reasons for investing in a mill is the health and flavor benefits of freshly milled whole grain flours.
Whole grains have extremely long shelf lives – especially when contrasted with whole grain flours. Most grains, when stored properly, can be kept for many years.
Since we talked earlier about extraction rates, home milling allows you full control over what extraction rates you choose to use. It should be noted that unless you use the portion sieved out, you do increase the effective cost of your flour.
So we can’t skip a quick discussion about grains – specifically wheat. Wheat can vary widely in protein levels, enzyme levels, flavor, etc – based on where it was grown, the local climate, the variety of wheat, the weather just prior to harvest, etc. Each individual harvest has it’s own characteristics.
There are also hard and soft wheats – start with hard – they are higher in gluten and are what white bread flours are made from.
We have come to expect that flour performs consistently from batch to batch. This is because larger mills test individual lots of wheat and mix lots to produce a consistent product. They also may add malts to insure consistent enzyme performance. The result is that we have consistent results by repurchasing the same brand and type of flour each time we bake.
When the home baker purchases grain, there is a very high likelihood that they are buying grain of a single variety from a specific single harvest. The quality and performance of the wheat and corresponding flour may vary from purchase to purchase… especially if purchased from different sources. The home baker should be prepared for this. Gluten strength may be higher or lower. Corresponding hydration levels will vary. Enzyme levels will vary.
Milling opens the baker to the option to mill a wide variety of grains and easily includes specialty grains and gluten free grains.
One may never fully appreciate a corn bread/muffin until they taste one made with fresh milled whole wheat flour and corn meal.
Flours can be used fresh after milling or can be aged. Allowing the flour to sit will cause it to oxidize. The gluten performance may improve slightly – but the flavor profile will also change some. If you do mill extra, just store it the same way you store any WW flour. It will keep for several weeks. Having done several comparisons, I almost always use fresh milled flours.
So – Let’s talk about some options for mills. Almost all mills leverage some pretty common concepts.
- Gravity – most mills use gravity to help feed grain into the milling chamber – very logical since gravity is free.
- Centrifugal force – the majority of designs rely on centrifugal force to help drive the grain through the milling environment.
- Two surfaces – one stationary and one rotating – often separated by a small gap which is wider where the grain enters and gets narrower towards the exit point. Most milling surfaces are round – often with grooves.
- A motor (or occasionally a hand crank) to provide power to turn the rotating surface.
So – most mills fit into a few categories (there will, of course, be exceptions):
Steel Burr / Stone Mills
Conceptually, both steel burr and stone mills function in a similar manner.
They use steel or stone surfaces – one fixed and one rotating. They most often have grooves to allow the grain to enter between the surfaces. The gap between the surfaces is adjustable and is effectively wider where the grain enters and becomes narrower towards the point of exit this is typically the grooves and not the surface itself). They tend to operate at lower rotational speeds. They effectively grind the grain into a flour. The coarseness of the flour is varied by changing the distance between the milling surfaces.
Stone mills historically were based on a pair of horizontal stones where grain falls into the center and is passed outward through centrifugal force and a set of narrowing grooves. Mills today utilize the same concept. Some mills use vertically oriented stones/milling surfaces. They method is still the same.
Examples of steel burr mills:
- Family Grain Mill (different design)
- Kitchen Aid Milling attachment
- Country Living Grain Mill
- Wonder Jr. Mill
Most hand powered mills are of this type.
Examples of stone mills
- Komo Mills
- Nutrimill Harvest Mill
High Speed Impact Mills
In a different design model, impact mills rotate at a very high speed. There is a fixed disc and a rotating disc. Both have steel teeth and there is a fixed gap between them (fairly wide).The grain falls into the center and is forced outward by centrifugal force where it impacts the set of fixed and rotating steel teeth. The grain is effectively exploded into flour as it passes through the milling chamber. Coarseness is controlled by varying the flow of grain into the chamber or varying the motor speed. They are great at making fine flours and not so good at coarser flours.
Examples of high speed impact mills:
- Nutrimill Classic
- Nutrimill Plus
Food Processors – newer food processors may include dry containers specifically intended to be able to mill grains. The blade is typically shaped to push the grain away from the blade. The blade is not sharp and functions more similarly to an impact mill – striking and exploding the grain.
Examples of food processors:
Each type of mill brings something a bit different to the home Miller.
Steel / Stone mills are typically quite versatile and can mill a wide variety of grains at varying degrees of coarseness/fineness. They will vary in size and speed.
Some steel mills do not produce very fine flours and this can be a drawback.
Some of the stone mills have wooden cabinets and are nice enough to be left on a counter. They are frequently fairly easy to clean. They often are the easiest mills to use and produce great results.
Impact mills excel at speed and the production of finely milled flours. They do not do cracked / coarse flours very well. Because of their high RPM. They have a characteristic whine and it will take about 30 seconds for the mill to “spin down” after the milling is complete. They tend to have quite large footprints and are not typically something you’d be too excited to leave on your counter. Each milling must be followed by a fairly extensive cleaning process.
Food processors will mill grains into flour – it should be with a container made for dry ingredients. They do not produce very fine flours. Unlike most mills, where the grain passes through the milling chamber, the grain is captive and longer times are needed to produce finer flours. They have an inherent risk of creating flour temps that are too high. If you already have one – it may well be worth a try – just watch the flour temp.
I will post a subsequent comparison of some different mills to give a more specific set of information.
Milling can be rewarding and there are rarely similar opportunities to have fresh milled whole grain flours – unless you live near a mill. It is an investment – with most mills lasting for years.
Join the new revolution – Flour Power!!