How is Flour Made?
Pastry Chef Rory Macdonald evaluates whether to mill his own flour.
For a recent project, I have been looking at buying a flour mill and milling flour, but before investing, I wanted to know what the real differences are between fresh milled and store or purveyor-purchased flour. Is it worth the effort? Can you taste it? Is it better for you and does it affect how you use the flour in a recipe?
Firstly, let's identify what flour is. It’s amazing to me how many people have no idea where flour comes from or how it’s made.
Types of Wheat
There are six classes of wheat — within which are around 30,000 varieties.
- Hard Red Winter
- Hard Red Spring
- Hard White Winter
- Soft White Winter
- Soft White Spring
The first four are most commonly used among bread bakers as the soft wheats have a lower proportion of protein and a higher proportion of starch than the hard varieties, which would be more applicable for pastries and other baked items, as they do not require the highly developed gluten structure that bread requires.
There are more than 54 million acres of wheat planted all over the United States. Adaptability allows the crop to be planted and cultivated in all different types of climate.
Once the wheat has been harvested it goes through a process called sweating before it gets milled. This process takes six weeks and creates small metabolic changes in the wheat berries that will improve the milling quality of the grain. The process will typically reduce the moisture content from 17-18% to around 13-14% after that time.
The next step is to put the wheat through a form of quality control to remove any foreign bodies, stones, sticks, stray grains, etc., followed by tempering, whereby moisture is added to the grain in the form of chlorinated water. This helps with the separation of the grain and stops any bacterial or microbial growth. In the U.S., the length of tempering time is around six hours, mainly due to the need for mass production. In Europe, more traditional methods typically temper the wheat for 24–48 hours.
Once tempering is complete, the wheat berries are ready to be milled and then sifted or bolted. The more the grain is milled, the smaller the grain gets, the more flour is obtained through the sifting process. From 100 pounds of grain, the flour yield will be around 75% extraction. The leftover bran and germ is generally used for animal feed. Whole wheat flour, for example, is 100% extraction, hence the color and flaked with bran particles.
Types of Mills
- Stone mills feature two large stones fixed to a platform. As the top stone turns it grinds the grain into pieces. The size of the grain is determined by how close the two stones are together. The milled flour is then sifted to separate the bran, wheat germ and white flour (endosperm). This is probably the oldest form of milling and the most reliable for maintaining the grains' nutritional integrity.
- Hammer mills use small metal hammers that repeatedly strike the grain in a closed chamber, pulverizing or shattering it into tiny pieces. Theoretically, the hammer mill is capable of creating a much finer powder than stone or roller mills. The milled flour is then sifted to separate the bran, wheat germ and white flour.
- Roller mills feature two revolving corrugated steel rollers, crushing the grain and separating the bran and the germ from the endosperm. The milled flour is then sifted to separate the bran, wheat germ and white flour. This is the system most favored by the milling industry and probably responsible for a majority of flour available on the market.
Regardless of which system is used, all mills reconstitute the flour by adding back a percentage of the bran and wheat germ to the white flour to create whole wheat flour. Because the milled bran and wheat germ particles are too large for most bakers to use, they’ll run these through the mill again to break them down into smaller particles perhaps further reducing the nutritional value of the flour. This means you may be buying whole wheat flour but not necessarily whole grain.
So what is the advantage of milling your own flour? Is it worth the effort? I spoke with Simon Bowden, the head baker for Leaven & Co., an artisanal bakery that produces bread for chefs in New York. Simon mills different kinds of wheat for various types of bread and explained that the seven main things to consider:
- Mixing and proofing notes.
Of the many benefits of fresh milling your own wheat berries, flavor has to be No. 1 by far. After all, isn’t great flavor what we all want when all is said and done?
When I first milled wheat berries in a small Mockmill designed as an attachment for my stand mixer, I was completely blown away by the aromas that came from the flour. It was overwhelming. I had no idea that flour could smell like this. When you smell commercial whole wheat flour you usually get a nice, somewhat sweet, wheaty kind of smell, but the fresh milled is nutty, fruity, earthy, grassy, super fresh ... It reminded me of being close to a freshly cut wheat field or freshly mown lawn, intoxicating and addictive. And those aromas only gain intensity as you hydrate the flour and mix your doughs.
Of course, this all translates directly to the overall taste or flavor, which in general is more complex, bolder, brighter, fresher and better than that of store-bought flour. Several people I know compare it to fresh grinding your own coffee beans. Once you smell the intense aromas of freshly ground coffee, let alone the flavor versus store-bought grinds, it's hard drink anything else. The same applies to the breads you can make using freshly milled flour.
To put this into context, I’m generally using anywhere from 5%-30% fresh-milled whole grain in my bread.
I’m certainly not an expert on the nutritional values of grains and flour, and I’m sure there are a lot of studies and research available that dig deeply into this area (and ICE Director of Nutrition Celine Beitchman gets into grain here). In general, we do know that freshly milled flours retain more of their vitamins, minerals and oils than aged flour. When the wheat berries are broken open at the mill, the resulting flour begins to immediately oxidize, which causes the nutrients to slowly start degrading. The longer it’s exposed to oxygen, the more loss of nutrients, as well as minerals and oils.
Perhaps another advantage of fresh milling whole raw berries is the ability to store them for much longer periods of time than aged flour, especially whole grain flour. If whole berries are stored properly in a cool dry and dark place, they can last almost indefinitely, and that means at least 1-2 years, even much longer. Whereas aged or store-bought flours have a much shorter shelf life, especially whole wheat flour, which is much more perishable since it still contains the bulk of the bran and germ. This is where most of the oils in whole wheat reside which is the primary reason for spoilage.
Choice and Provenance
Another huge advantage to fresh milling whole berries is the ability to buy many different types of wheat and other grains directly from farmers or the many mills here in the U.S. To be honest, it’s something I never thought of or tried until I was buying some flour at a local farmers market. Next to the flours were some whole grains from the same local miller, Four Star Farms in Northfield, Massachusetts. They had Warthog Wheat and Zorro Wheat, which I’d never heard of but definitely wanted to try. These are hard red winter wheats with reasonably high protein content.
That was the incentive to purchase my first mill, an attachment for my stand mixer from Wolfgang Mock. It's fun and really easy to use for small batches (more on mills below). The smell and taste of the resulting bake of the Warthog was eye-opening to say the least. I’d never tasted anything quite like it: super fresh, earthy, nutty and slightly sweet. Then I tried the Zorro berries: again, really fresh, definitely nutty and a little sweeter than the Warthog. I was hooked.
I’ve tried many varieties since, from ancient grains to modern wheats, from many different farmers and mills. Glenn, Turkey Red, Red Fife, Redeemer, Sonora, Yecora Rojo, Rouge De Bordeaux to name a few. Plus some of the ancient grains, Einkorn, Emmer, Spelt and Khorasan. I’ve also fresh milled rye, corn, barley and oats. I know where they come from, how they were grown, when they were harvested, how they were stored and much more. This is information that’s invaluable when marketing and selling your freshly milled bread.
Here’s a brief list of some grain sources I’ve ordered from:
- Anson Mills
- Barton Springs Mill
- Camas Country Mill
- Carolina Ground
- Castle Valley Mill
- Farmer Ground Flour
- Hayden Flour Mills
- Heartland Mill
- Maine Grains
Grain Milling Equipment
There are many stone mills now available on the market, from the Mockmill attachment previously mentioned to a large or industrial-sized mill suitable for a local bakery that’s going to freshly mill a larger portion of flour. I’d definitely recommend the Mockmill attachment for stand mixers as a great place to start at home or even in a bakery for smaller batches for a cost of about $200. For a larger countertop mill, I’d suggest either the Mockmill 100, Mockmill 200 or the professional Mockmill 200, which range from $300 to $700. I’m currently using the 200 and can mill about 10 pounds of flour in about 20 minutes.
At a similar price range is another very good countertop mill: the Komo Magic Mill, which ranges from about $500 to $1,000 depending on size. We used this at San Francisco Baking Institute and could mill continuously for hours if needed. For a bigger production, the next step up could be to a much larger Meadows 8” mill, which will produce about 50 pounds per hour. These start at around $2,000. I haven’t used a Meadows, but a good friend of mine who mills a lot of flour highly recommends this model. Then there are New American Stone Mills, a stunning-looking, larger 26” mill that can produce about 80 pounds of very fine flour an hour. This one's perfect as the centerpiece of a bakery that specializes in milling a lot of its own flours and starts at around $15,000.
As another point of reference in terms of ease of use: I’ll fill the hopper of my Mockmill 200 with berries first thing in the morning while I’m scaling other ingredients for mixing. The flour will be a little warm from the grind so mono adjustments in water temperature might need to be made. You can also mill last thing at the end of the day while feeding levain, etc.
Mixing and Proofing Flour
Just as we have to occasionally adjust to mixing and proofing different types of aged flours and different batches of aged flours, we have to pay equal attention if not more when using freshly milled flours. These aren’t drastic changes but definitely require some getting used to. In general, I find that there’s quite a bit more activity in the initial fermentation using fresh-milled flours versus aged flour, so keep an eye on your first proof and if needed, change FDT a degree or two to compensate for the extra activity. The same can also apply to overnight retarding, and keeping your FDT a little lower before retarding can help adjust the final proof time.
Percentages of Fresh-Milled Flour
As I mentioned above, I’m generally using up to about 30% fresh milled whole grain in my bread depending on what I’m making and what I’m looking for in terms of flavor, texture, crumb, etc. I’m mixing the fresh milled with aged flours like King Arthur Sir Galahad and King Arthur Sir Lancelot, which are generally very consistent overall just as milled aged flour should be. But even when I use a small percentage, around 5-7% in a baguette, I’ll notice a difference in overall flavor from the regular aged flour. At these ratios, the irregularities that one might expect using grains bought directly from a farmer and mailed on-site are fairly easy to manage and adjust to in terms of overall production.
I’ve been fortunate to have spent time with two bakers who are buying all their grain directly from local farmers, milling all their own grain, sifting their flours and then using them to make all their bread. They are very experienced bakers who are looking to make a very particular type of product for a certain kind of market and are willing to take on the difficulties of producing bread this way. From this limited observation, I’d say working with 100% freshly milled flours is a challenge for the most experienced bakers to say the least. The results when executed well can be extraordinary, but that path is not for the faint-hearted. So if you’re tempted to step into that world, do so with caution.
Simon Bowden, SIMON’S BREADS
Adam Leonti, FLOUR LAB
Peter Rhinehart, BREAD REVOLUTION
Maurizio, THE PERFECT LOAF
Jeffrey Hamelman, BREAD
Roxana Jullapat, MOTHER GRAINS