Which method produces better flour: grinding with traditional millstones or with modern steel roller mills? Before we share our thoughts, take this simple true-or-false quiz to see what you already know about milling grains into whole grain flour – flour that contains all of the grain kernel’s original bran, germ and endosperm. We’ll reveal the answers throughout the blog.

T or F

1. Stoneground flour is always healthier and more natural than flour made in big industrial steel-roller mills.

T or F

2. If the label says “stoneground wheat” the flour is always whole grain.

T or F

3. Before steel-roller mills became widespread in the late 1800s, all flour was whole grain.

T or F

4. Modern steel-roller mills don’t really produce whole grain; they leave out part of the germ or bran or both – and FDA says that’s okay.

Is stoneground flour healthier? Some popular websites and books say that traditional stone mill wheels grind grain more gently, at a lower temperature than the big industrial mills called roller mills. Temperature’s important, because high temperatures can destroy key nutrients in grains.

Research shows, though, that stone mills generally operate at much higher temperatures than roller mills – as high as 90°C/194°F for stones vs. 35°C/95°F for roller mills. Plus, roller mills work so efficiently that the flour they produce is held at top temperatures only briefly, while stone mills take longer to reduce the grain to flour particles. That could explain why some data show stone-milled flour having greater loss of amino acids and healthy fats.

Stoneground grains often have a larger particle size than those ground in roller mills. This means that breads made from them may have a slightly lower glycemic index (healthier for your blood sugar). At the same time, though, studies show that vitamins and minerals may be less bio-available in larger particles. We give #1 a False, based on the data. Whole grain flour has the potential to be healthy either way, as long as the miller has taken care with the process.

Osttiroler Mill
A stone mill (photo courtesy of Osttiroler Getreidemühlen)


Does stoneground always mean whole grain? Roller mills usually divide flour into separate “streams” as they grind it, then recombine everything to produce whole grain flour. Stone mills keep everything all together during grinding, in what’s known as single-stream milling. But that doesn’t mean millers couldn’t sift out some or all of the bran after the flour is milled, so while #2 is usually true, stoneground is no guarantee of whole grain, so read labels carefully. And that leads us to some interesting history….

Was all flour whole grain before roller mills? Before I started working with the Oldways Whole Grains Council, I had a more “black and white” view of grain history. I figured pretty much everyone ate healthy whole grain bread before roller mills became widespread, and then zap, suddenly white bread was everywhere, right? Wrong.

Historic sources show that two thousand years ago Roman millers sifted their flour to create a whiter bread for their better-off clients, and the practice persisted through the centuries. (After all, no one knew about the health benefits of bran and germ, but they knew white flour kept fresh longer and was easier to bake with.) That quaint gristmill by the stream in colonial America, in fact, often included sifters and shakers to remove some of the bran (along with rocks and dirt). That said, older sifting processes weren’t very thorough, so the flour likely kept more of its good stuff than today’s white flour. Conclusion: #3 turns out to be False as well.

Modern Steel Roller Flour Mill
An industrial steel roller mill (Fotolia photo)


Is industrial whole wheat flour really whole? Another widespread rumor has it that industrial roller mills leave out part of the original wheat kernel – often the germ, whose unstable healthy fats shorten the flour’s shelf life. One way to check this is on the flour’s Nutrition Facts Label. White (refined/enriched) flour has total fats of under 1%, while whole wheat flour has about 2.5% total fats. If the germ had been taken out, the fats would be similar to white flour.

In the U.S., federal regulations require that all of the wheat’s original bran, germ, and endosperm “remain unaltered” for flour to be called “whole wheat flour.” While we can’t vouch personally for every miller in the country, we call “False” on the claim that industrial whole wheat flour isn’t really whole grain.

If you’re reading this in Canada, however, be aware the Canadian law allows up to 5% of the original wheat kernel to be missing in “whole wheat flour” – so all of the germ and a bit of bran is often left out. If you’re Canadian, look for “whole grain whole wheat” – a term that would be redundant in the U.S.

It’s all good. Our conclusion is that all sources of whole grain flour contribute to making delicious breads, crackers, pasta and other foods, and you can’t go wrong with either fresh stone-ground flour or fresh, good-quality roller-milled flour. (You can even mill your own at home!) In fact, what happens to that flour after it leaves the mill may affect its health benefits more than anything that happens during milling. We’ll be looking into some of those factors in the coming weeks.  (Cynthia)

Sources: Information in this blog, unless otherwise linked, comes from the article “Nutritional Impacts of Different Whole Grain Milling Techniques: A Review of Milling Practices and Existing Data.” Cereal Foods World, May/June 2015, Volume 60, Number 3, by Julie Miller Jones, Judi Adams, Cynthia Harriman, Chris Miller, and Jan-Willem van der Kamp.



This is the first post in our series on whole grains and processing. Click below to read the related posts in this series:


I grind my own flour from whole wheat berries in a Vitamix grain container. I do notice the resulting flour gets very warm - According to this article, if I am understanding correctly, the warmth generated by the grinding is harmful and decreases nutrients ?
Warmth is inevitable with grinding -- it's a friction process, after all, and friction creates heat. As we mentioned in the blog, though, the problem comes with very high temperatures maintained for long periods. You could stick an instant-read thermometer in your finished flour and compare it to the temperatures we cited for commercial stone and roller milling -- but we're betting your fresh flour stays at a reasonable temperature, cools off pretty quickly, and still has LOTS more nutrients than store flour that may have been sitting on the store shelf for a while. Grind and enjoy!
I love this Topic
Is the issue of overheating the flour a bit redundant, as it's going to be cooked anyway? I could see it being an issue in live starters, but not really from a nutrient POV, unless I'm missing something?
Hi Will -- Since grains are almost always cooked before consumption, most consumers don’t worry too much about the milling temperature’s impact to the nutritional content of their flour. We know from the large body of health research about whole grains, that grains maintain significant nutritional benefits despite being cooked/heated. However, nutrient loss or degradation can have an effect on the stability of the flour, which is why it is a concern in the milling process. When the germ and other components of the grain are heated to 60°C or higher, these temperatures can trigger rancidity or contribute to a much shorter shelf-life for the product.
Good day - thank you for posting this topic. I do not grind my own whole wheat flour but I do only use it for all baking - for bread I do not sift out the bran and have had great success with yeast breads - however - for cakes and pastries I do sift out the bran, twice - once through a regular sieve and again through a finer sieve - not all bran is removed just the large coarse bits - so my question is, is what I am doing still a more healthy option than using regular all purpose white flour? Many thanks in advance!
Hi MJ – We’re glad you found the topic of milling interesting and love hearing that you use whole wheat flour in your breads. The bran layer of a grain contains important antioxidants, B vitamins, and fiber, so sifting some of the bran out of your flour does remove some of these nutrients from the flour. That said, commercial white flour has all of its bran and germ removed, so your partially-sifted flour will very likely maintain more of its original nutrient content than all-purpose white flour does.
Thank you for your informative website. I mill my own berries. From what I have read, when you sift out the bran, you also remove the germ. How do I remove some of the bran without also removing the nutritious germ?
Hi Nancy -- Both the germ and bran layers are full of nutrients, which is why we at the Whole Grains Council strongly recommend keeping your grain whole and eating all three parts of the kernel or berry: the bran, germ, and endosperm. The different layers of the grain do not always fracture neatly when milled, leaving particles of only bran, only germ, and only endosperm, but the particles that contain the most bran do tend to be larger (making them relatively easy to sift out). This sifting process will remove more bran than it does germ, but there will be some losses of both. The best way to get the full benefit of your grains is simply not to sift out or remove any parts.
We are going to be milling our own flour from the wheat we grow here in Canada and just sell it "farmer's market style" either in person or online. What confuses me is all the names/designations depending on the milling/sifting process. I understand that if we grind the entire berry and avoid any sifting, that it is designated Whole Grain Flour. But what do you call it, if once you grind it, you sift out much of the bran? (from what I understand, much of the germ remains in the flour and so would not be called an all purpose or a white flour and would also require refrigeration to avoid the spoiling that the germ can cause when left behind??). We will be selling both but "farmer's market style" allows us to sift out some of the heavy and sharp bran that punctures the bubbles formed in the yeast process without having to enrich it artificially, but still create a product that create's a bread texture closer to a white flour. Its just confusing as to what it's designation would be.
Hi Rob – Here in the US, the flour you are describing – where some of the bran has been sifted out – would typically be called “wheat flour” or “sifted wheat flour.” Please note, though, that while we know a lot about Canada’s guidance around whole grains and whole grain flours, we aren’t familiar with its guidance on “farmer’s market style” flour and we encourage you to reach out to local health or government officials for clarity on the relevant labeling rules.
Bob Klein
Roller mills separate the grain. bran, germ and endosperm, then mill each separately. The germ contains most of the fats which when milled go rancid. How do roller mills stabilize the germ before adding it back to the whole grain wheat flour?
Whole wheat flour will typically have a shorter shelf life than refined all-purpose flour due to the oils in the germ. Some processors have the capacity to inactivate the oxidative enzymes (lipase and lipoxygenase) in the wheat germ. Regardless, wheat germ does not go rancid immediately (just as oils do not go rancid immediately), and can be enjoyed at home after being milled. Food tastes and performs much better when it is fresher, so we recommend only buying what you can eat in a couple weeks or months time, and storing extra flour in the fridge or freezer to extend shelf life.
Because milling the wheat kernal crushes it so that the bran, germ & endosperm are separate but mixed together don't you essentially have white flour in the mix? So that unlike brown rice in which the kernal is intact whole wheat can never truly be all whole wheat? If so, then don't you have a glycemic/gut issue regardless, unlike for an intact whole grain kernel?
Great question! Any grain that contains all of its original bran, germ, and endosperm in their original proportions is considered a whole grain. The nutritional content of milled whole grains (such as whole wheat flour) does not significantly differ from the nutritional content of intact whole grains (like wheat berries). In other words, the fiber, vitamins and minerals don’t “disappear” just because they get ground into smaller pieces. However, processing grains into smaller particles does impact the glycemic response, with smaller particle sizes being linked with a higher glycemic response, generally speaking. Regardless, eating more whole grains (whether milled or intact) is correlated with a variety of health benefits and lower risk of many chronic diseases. To learn more about how processing whole grains impacts their nutrition content, we encourage you to view this 1 hour webinar: https://www.youtube.com/watch?v=3E9bPuTIMHU

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