The Fresh Loaf

A Community of Amateur Bakers and Artisan Bread Enthusiasts.

nutrition of flour after being milled....

DanOMite's picture

nutrition of flour after being milled....

I had a co-worker tell me today that after 24 hours of being milled that all nutrtion in flour is lost. Is there any truth to this? I'm really quiet curious to know...I remember reading in peter reinharts whole grain book that after flour is milled it has to be used within like 8-24 hours or you can't use it for like two some odd weeks.  That could make sense because obviously its going through a shock of being a berry into powder. But I don't see how its possible that all nutrtion is lost. I've been using King Arthur whole grain flours and everytime I use them and eat the bread my fiber levels are up higher.

Could anyone share some light on this

Or should I just try to ignore what I heard because its not true?

I hope sombody's got some answers because this bugs me...

Thank you for all your help in advance...


blaisepascal's picture

There are some important ways in which that assertion is wrong.

For one thing, folks who say things like that forget that sugars and starches are nutritive.  They assume they are valueless filler.  In truth, they are what has made bread "the staff of life" for millenia.  

What they are concerned with is the destruction of vitamins, minerals, oils, and proteins.  Some, but all, are vulnerable to degredation with time.  But 24hrs too fast.

But without protein, bread won't make a risen dough, as gluten is a protein.  Since people make bread all the time with store-bought  flour, clearly the gluten isn't destroyed. 

It's well known that freshly ground whole wheat flour, if stored at room temperature with plenty of access to oxygen will, after a few weeks or months, go rancid.  That rancidity is caused by the oxidation and breakdown of the oils in the wheat.  Before it goes rancid, the oils are still there.

While there may be some minor degradation of nutritional quality, it's not significant over the first 24 hours.

Yerffej's picture


Thanks for that link as it is a really nice article.


prairiepatch's picture

I enjoyed the article too Rockfish.  Thanks.

Here is another article on the same subject.  The following few lines are from that article.  Although how do you know how acurate anything is on the internet. Right?  Again these next words are not mine but come from that article with the link to it following.

"A little research bore out our family's observations. It turns out the original whole wheat grain is a power house pellet chock full of nutrients, yet if you buy pre-milled flour in the store up to 88% (1) of some vitamin and mineral content is already lost, and the remaining nutrients are contaminated with bleaches, caramel coloring, emulsifiers, mold retardants, texture agents and a host of other...",+the+quicker+you're+dead-a0133411456

subfuscpersona's picture

DanOMite on September 22, 2008 wrote:
I had a co-worker tell me today that after 24 hours of being milled that all nutrtion in flour is lost. Is there any truth to this? I'm really quiet curious to know.

Commercial flour milling is a complex subject and, without the details of how your store-bought flour is milled, stored, aged and transported, you will *never* arrive at a satisfactory answer.

Furthermore, if you purchase whole grain *flour* (such as 100% whole wheat flour) you will be generally clueless about the quality of the grain purchased, the (commercial) milling techniques, how long the flour was stored and the time elapsed between milling, packaging, transportation, and storage at the local outlet (your supermarket or coop or whatever). Your only hope is to purchase flour from a reliable supplier and to know the flour specifications of that brand of flour.

Home milling is a different subject. In this case, you, the baker, purchase whole grains and mill the quantity you need for one baking.

As a *home miller*, you control your flour. You are responsible for the quality of the wheat (or other grains you purchase). You are in control of the storage conditions of your grain and the flour you mill from it.

For home milled flour, do remember that the outer portions of the endosperm, the bran coating and the germ contain the bulk of the *minerals* in the grain. Minerals are not subject to destruction by heat. You will get the full mineral complement of your grain in your flour.

Vitamins, on the other hand, *are* subject to degradation by exposure to prolonged heat. This is *almost never* an issue in home milled flour. Around 140F is the magic number where vitamins *may* be destroyed. In repeated tests using an electric flour mill (a Nutrimill micronizer mill) and measuring the temperature of the milled flour immediately after milling with a digital thermometer, I never found the temperature of any flour to be over 130F. Furthermore, the home miller can easily and rapidly dissipate any heat in fresh milled flour simply by stirring the flour and /or pouring it from the mill's flour receptacle into a separate bowl.

The bioavailability of minerals in whole grain flour (especially whole grain wheat and rye flour) *is* affected by the techniques used to make bread dough. Bioavailability refers to the ability of humans to absorb and make use of nutrients in your flour. There has been a lengthy discussion of this topic on TFL and I will find the thread reference for you if you are interested.

Lastly, be cautious how you interpret and research information on this topic. There is a great deal of incorrect information on the "web" on this topic. A great deal of it is fueled by vendors who are selling some product, and the rest is the result of writers who mindlessly repeat this mis-information.

You can, in fact, find valid scientific studies on the web that address these issues. However, to properly interpret them in context, you must have some grounding in the scientific method and statistical analysis.

This general topic periodically rears it's head on TFL and other forums. I am sympathetic with bakers who wish to produce good tasting bread with maxiumum nutrition. However, there is clearly a great deal of mis-information that gets repeated and wins credence simply by repetitition. Always ask yourself whether the information you read is from a trustworthy source, is supported by *facts* from a reliable source and - last but not least - sounds reasonable.


subfuscpersona's picture

DanOMite on September 22 wrote:
I had a co-worker tell me today that after 24 hours of being milled that all nutrtion in flour is lost. Is there any truth to this?
Mike Avery is a professional baker and teacher. He is a long-time member of TFL, and every post of his I have ever read is right on target and contains valuable information. A very similar question to yours was posted by TFL member "staff of life" on June 26 - see Mike's reply to that query can be found at but, for your convenience, I'm going to repeat it here... ===== from Mike Avery =========== The only people who talk about the nutrition value of freshly ground flour are people with a dog in the race. People who are selling mills, freshly ground flour or baked goods made with freshly ground flour. The web pages that promise good health and say, "all we changed was our bread" are inevitably pushing freshly ground flour or the equipment to make it. Is it really better? I don't know because I haven't seen an independent study. I'd love to see some. Annecdotal evidence IS important, it is persuasive, but it isn't proof. All too often you find that someone who had health issues changes a lot of things at once and doesn't think about them. The one that took a lot of time was grinding the flour and baking the bread, so that's what they focus on. I'd like to see chemical analyses of the flour when it's freshly ground and again every day or two for a month, and every week or two for a few years. Or even with less frequency, but still offering some degree of history to the same flour. And then I'd like to see some sort of study as to what impact that would have on people. My take on the matter? From what I hear somewhere between 120 and 140F is the critical temp. You don't want to go past that. And neither my micronizer mills nor my KitchenAid mill raise the temps too far. The only thing I know of that decomposes is the fatty acids in whole grain flours which will go rancid. Rancidity is distatesful but it is not a short term health risk, though some people point out the oils are oxidised and could speed oxidation in your system. Still, if you're hungry you can eat goods made with the rancid flour without becoming ill. It won't be appetizing though. How long does a whole grain flour last? It depends on storage conditions, but 6 months to a year at room temperature, if memory serves. The breadmaking characteristics are another interesting matter. Many people like to make bread with freshly ground flour, flour "still wriggling with life" as Alan Scott put it. And it works pretty well. However a few days later, that flour can be very hard to use - the dough is so elastic it is very hard to work with from all reports I've heard. At that point, letting the flour age a few weeks will restore it's baking characteristics.
gavinc's picture

I don't know what the situation is in USA, however in Australia a minimum amount of nutritional information is law on all food products.  I use this information to quickly see the protein percentage of the various flours as they have to show the grams per 100 g portions as well as suggested serving sizes.  I've uploaded a couple of flour labels to give you the idea. 

bread flour 11.9% proteinGeneral purpose unbleached 10% protien

TorontoFlour's picture

Well I've been googling for hours and read this informative post too. But I am still puzzled:

Everything I read says that the oils in the germ of the wheat in whole wheat flour will go rancid in a few days, And then I hear this from a whole wheat flour miller in Ontario, Canada (in response to an email from me):

"When using a stone grinder the oils in the germ are dispersed into the flour at a lower temp and without the electrical charge that is produced by steel roller mills causing the flour to be stable. We offer a shelf life of over a year. We actually have some consumers that require the flour to be at least a few months old before they will use it due to the natural aging process. So the bottom line is our flour does not need refridgeration."

but now DanOMite, above, says "How long does a whole grain flour last? It depends on storage conditions, but 6 months to a year at room temperature".

So, my questions are:

1. Is it then true that the shelf life, which is based on how long it takes for the oils in the whole wheat flour to go rancid, is based on the milling method? ie steel roller vs stone grinders?

2. If it is steel rolled, just what is the shelf life?

3. Do processors that sell whole wheat flour that is steel rolled and has not had the germ or germ oil removed and is sitting in packages at room temperature on store shelves put some type of preservative in it to make it last longer? If so, what?

Thanks, but I want to get to the bottom of this!

TorontoFlour's picture

Those answers are fascinating and really helps one understand what is going on. I have searched elsewhere quite a bit for that kind of detail about what really goes on when and after wheat is ground but did not find much. Of course now I have more questions!

The benefits of air-sealing the package would cease once the package is opened, so I wonder then how Bob's Red Mill is able to claim the product will taste as good as they day it was bought 24 months later even if it was refrigerated or frozen after opening. Wouldn't that really depend on when you opened the package?

I am not sure if King Arthur's package is even air sealed as I haven't been able to get my hands on one. It appears to be a paper bag so maybe not. I am not sure whether they recommend on the package refrigeration or freezing after opening. But, they claim a 6 month life I think. But again, are they not just guessing too?

Also, I know that Bob's Red Mill claims the product will taste the same 24 months later but it appears they are just guessing as they admit they don't do any tests and just use a rule of thumb (which maybe has been derived from customers complaints). Is it not likely that the product has, by that time or much earlier, gone rancid and customers just really don't know as they just use the flour without paying much attention? 24 months is a long time, given the practice that people like yourself and others follow of using the flour immediately or within one month after grinding. Before I started getting serious about baking I didn't even know that whole wheat flour could go rancid so I wouldn't even think to watch for it. I'd just use it. Once my Komo Magic grinder arrives that certainly will all change.

The local manufacturer (the one that told me about the electrical charges) said that some of his customers like to let the whole wheat flour sit for 3 months after milling because they like the taste better. I take it then they like it when the flour has deteriorated a bit and gone a bit rancid. What else could it be?

Thanks for your valuable input.



TorontoFlour's picture

Actually this local manufacturer was talking about stone-milled whole wheat flour when he mentioned that some like to let is rest for 3 months. I didn't think that that made whole wheat flour taste any better!

snihan's picture

Reading through this post a lot of people are comenting on how the grain is ground, where depending the high heat of the grinding process it can kill nutrients.  One person asked a question that has been in my head for quite some time, but there was no response to their question.  Most of my recipes call to bake my bread at 350/375 degree's, now what nutrients make it through that baking process?  Earlier it was stated that nutrients are killed in heat over 140 degrees. 

So if home milled grain or store bought grain is being used, does it matter, becuase both are going into high heat ovens? 

thanks again for any insight you can offer!



Jo_Jo_'s picture

Thanks for the link to Sue's site.  I have been seeing things online talking about soaking fresh ground flour  before making it into bread, and in fact am making a couple loaves right now that the flour soaked for 20 hours before making into the actual dough.  This is to remove the harmful phytic acid, but from reading Sue's site it is giving my the "other" side of the coin so to speak.  There is definite evidence that the opposite is true, that phytic acid might be helpful in a lot more ways than I had first realized.  I hate when I can only find one side of an issue, so having the other side of the coin really helps a lot.