unbleached vs bleached


I'm new to "quality" baking. I've most always just purchased flour in the grocery store, not paying attention to whether or not it is bleached. I'm trying to learn more about quality ingredients and would like to know when to use unbleached flour, when to use bleached flour, and what the difference is. Can anyone point me to this information? Thanks.

badge posted by: jpuckett3 on August 31, 2011 at 11:21 pm in General discussions
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reply by: KitchenBarbarian aka Zen on September 01, 2011 at 12:54 am
KitchenBarbarian aka Zen

The short answer is I wouldn't (and don't) worry about it. However many people think it does matter. I can't say that's wrong for them, it just isn't right for me (there is a difference there, LOL!). The most important thing for a new baker, IMO, is to pick a flour and stick with it. You can adjust for almost anything, as long as you don't have to keep adjusting from one loaf to the next! The long answer follows:

The bleaching process doesn't change the actual protein content, but (according to "How Baking Works") different bleaching processes affect gluten strength.

Ascorbic acid, Potassium Bromate, and natural ageing are all maturing processes that strengthen gluten. Potassium Bromate isn't used much in the US anymore; you can tell (in the US) if it's being used it will be listed as an ingredient. I believe Ascorbic acid (basically Vitamin C) would also be listed as an ingredient.

Peroxidation has no effect on gluten. This is a commonly used process - many mills that used to bromate the flour now use a peroxidation process. To my knowledge bromated flour is banned in Europe. Peroxide will NOT be listed as an ingredient, the flour will just say "bleached".

Only chlorine weakens gluten. This will also not be identified as an ingredient.

Unless the flour is chlorinated to bleach, I wouldn't worry too much about whether or not the flour is bleached or unbleached. I can't tell the difference in performance between flour bleached with the benzoyl peroxide and naturally aged flour, but then all my bread attempts are pretty pedestrian. I don't think most people would notice any difference though.

However, other people have a different opinion. Some people swear they can TASTE the difference (I can't).

The one thing that is often said about bleached vs unbleached flour that I CAN refute is the idea that absorption rate differs (the rate at which the flour will absorb moisture and make a cohesive dough, this has an effect on rising, taste, and gluten development). The details are in this thread, but suffice it to say that when talking about the same wheat, bleaching doesn't affect absorption rates. However, which KIND of wheat has been used to mill the flour DOES make a difference. So with a flour like KA that is made from all one kind of wheat (I think it's hard red winter), you will see a different absorption rate than another flour that is milled from a mixture of different wheats, even if they ultimately have the same total protein content. In this case it's the wheat that's used and not the fact that one is unbleached and the other (may be, is probably) bleached. (Again, discounting chlorinated flour).

reply by: Mike Nolan on September 01, 2011 at 2:05 am
Mike Nolan

I can smell a difference between unbleached flour and bleached flour before it is baked, less so afterwards.

I can also see some differences in the finished breads.

Breads made with bleached flours don't tend to rise quite as much and IMHO brown differently.

I have done side-by-side tests, though it is hard to say how much of the differences were due to bleaching and how much were due to differences in the type of wheat in the flours used.

Every now and then I get a fifty pound bag of flour from my neighbor, who runs one of the local restaurant suppliers. I usually start out by doing a double batch of white bread with the new flour and with KAF AP flour, so I have a basis for comparison.

FWIW, most cake flours are bleached, the EU prohibitions on bleaching agents is apparently creating some interesting challenges for cake bakers there.

But I do agree with Zen that you should stick to the same brand/type of flour, or maybe just a couple of them, like AP and bread flour, at least until you feel you can compensate for the differences in flours. (Most brands have a bit of variance anyway.)

And I will repeat my advice to take notes on what you do, and how it worked. That way you will be better equipped to repeat your successes.

However, this advice is coming from a guy who has at least 8 brands/types of wheat flour in his kitchen, along with two types of wheat berries and a home mill, so you may want to take that into account. :-)

I use KAF AP flour the most, though.

reply by: KitchenBarbarian aka Zen on September 01, 2011 at 9:10 am
KitchenBarbarian aka Zen

Yes, I should have mentioned that chlorinated flour is actually desirable for cake flours. Even KA carries a bleached cake flour (they carry an unbleached version as well, but the Queen Guinevere is chlorinated).

I thought only the bromated flour had been banned in Europe - Mike, are you saying ALL bleaching has been banned in Europe???? I really think that's carrying things a bit too far if that's the case!

Oh yeah, and I should have said in the first post, when you're just starting out it's important to PICK A FLOUR APPROPRIATE TO THE PURPOSE and stick to it. There's not a lot of point in trying to bake bread with a pastry flour, say, that's 9.2% protein when you want to make bread, which is better served by something in the range of 11.5% to 12% protein.

KA AP flour, btw, comes in at 11.7% protein. A lot of commercial brands (like Gold Medal, etc.) of BREAD flour are about the same.

KA Bread flour is 12.7% protein, a bit higher.

Typical AP flour is about 10.5% protein, plus or minus 0.5%. AP flour varies a lot regionally. I buy flour labeled AP here in the SE US but when I contacted the mill it turned out it is only 9.2% protein. Same flour, bagged by the same company but turned out by a different mill, is closer to 11% in the Northern Great Plains. AP is generally milled from whatever wheat grows locally, which here in the south is lower protein, softer wheat, while in the North it's higher protein, hard wheat. Hence the regional preference in the South (historically) for biscuits that do well with a lower protein flour.

I KNOW I edited that into my original post, I wonder why it didn't take???

reply by: Mike Nolan on September 01, 2011 at 10:06 am
Mike Nolan

It's possible I had already posted my response by the time you tried to save your edited version.

For reasons unbeknownst to me, KAF disallows editing a post once someone has directly replied to it. (I think that's a common setting on web forums to keep people from flame fests where person Y responds to person X, so person X edits the original post then responds to Y "But I didn't say that!".)

Seems unnecessary here, but may not be at the top of KAF's 'things to fix' list.

I'm not 100% sure about the ban on bleaching of cake flour in the EU, but some of the posts I've seen here and elsewhere seem to indicate that. For example, wiki:


But overreacting seems to be a common political trait both in the EU and in the USA. (Like the ban on incandescent light bulbs!)

BTW, the Wiki piece says that bleaching leads to higher loaf volume, which is opposite to what I've noted in my tests, so I may be seeing more impact from other differences in the flours.

reply by: kidpizza on September 01, 2011 at 12:11 pm

Good morning to you. Jean, I am going to just answer your question directly like I always do. SIMPLY PUT.... If possible, always employ un~bleached flour. But & however there is a exception to the rule. When your recipe for cakes, muffins, loaf cakes, & tea cakes & pie dough call for solid fat, ie, butter, shortening, cream cheese, use BLEACHED FLOUR. (In USA cake flour is bleached) Your baked product will love you for it. You will be able to cut your cake with a feather.

Good luck & enjoy the rest of the day young lady.


reply by: Tom_B on September 01, 2011 at 12:54 pm

This forum at KAF is pretty respectful and nice about these things. We try not to get very judgmental about things, because it usually doesn't help your baking.

People here in KAF forums and elsewhere do have their preferences and some have *very* heartfelt beliefs on the bleached / unbleached flour question.

My take on in it is that even if bleached is "wrong" or "evil" (I don't think it is, BTW) that it's just a bag of flour and not the end of the world. Just use it up, see what it does and go from there. If you like it, great. If not, go unbleached next time and see what happens there.

I personally would suggest that everyone try both bleached and unbleached and see the differences for themselves in what they bake. After that, you can overlay any other concerns that you may have with bleached flour over that data point.

reply by: jpuckett3 on September 01, 2011 at 1:12 pm

You guys ROCK. Thanks so much for all the information.

reply by: KitchenBarbarian aka Zen on September 01, 2011 at 4:42 pm
KitchenBarbarian aka Zen

I think certain bleaching processes can lead to higher loaf volume in commercial settings - you know, like Wonderbread factories. I doubt chlorination is one of those processes, but I'd be willing to bet most commercial bread is made with bromated flour. Bromation is one of the processes that INCREASES gluten strength, and apparently it's cheaper and/or easier and/or quicker than going with something relatively neutral like ascorbic acid.

reply by: Mike Nolan on September 01, 2011 at 4:52 pm
Mike Nolan

Have you ever toured a Wonderbread factory? It bears almost no relationship to something most of us would recognize as bread making!

I suspect bleaching and brominating both started out as ways for mills to be more consistent in their product at a lower cost.

Bleaching, in particular, appears to allow them to get a higher extraction rate from the wheat. More flour per ton of wheat means a lower cost per ton of flour produced.

reply by: Mike Nolan on September 01, 2011 at 4:59 pm
Mike Nolan

The more you learn about flour, Jean, the better you will be able to bake. And the more you learn about flour, the more it seems you have yet to learn. :-)

If anyone had told me six years ago that I'd be able to discuss things like extraction rate, ash percentages, wheat types and protein content, I'd have said they were crazy. Now I can, and have, held my own in discussions with professors who teach grain science.

reply by: BakerIrene on September 02, 2011 at 3:59 pm

Here in Canada we have various brands of flour that come in both AP and unbleached, with the same protein and ash on the label so it's probably the same stuff through different processes.

There is a MAJOR difference in quality. The unbleached is better for bread baking, for ALL brands. The bleached AP is better for pie crust and cake, for ALL brands. One particular brand (5Roses) of unbleached handles very much like KAF AP--yes, I hauled bags of flour across the border and did chemical analyses and side-by-side baking tests.

I believe that the bleaching process alters the gluten molecules even though the total nitrogen analysis (which is how "protein" is really measured) doesn't change.

So for bread baking, do not waste your time or money on anything except unbleached hard flour, or hard whole what flour. if you can't buy KAF locally, go and bug your local health foods store to order unbleached hard wheat flours in bulk for you. They will understand why.

reply by: Midnite Baker on September 03, 2011 at 4:22 pm
Midnite Baker

Hi, A baker friend did a comparison. You can check it out here:

reply by: KitchenBarbarian aka Zen on September 03, 2011 at 5:59 pm
KitchenBarbarian aka Zen

Yes, well, when comparing flours, it is best to compare roughly EQUIVALENT flours.

The Gold Medal flours in those "tests" were the retail AP types that range right around 10% protein (give or take 0.5%).

However, KA AP flour is actually 11.7% protein, which is basically bread flour.

OF COURSE the KA made the better bread! That's what it's made for! GM AP flour, in contrast, is "typical" AP flour - it's sort of the "master of all trades" of flour. You can use it to make bread (sort of), pie crust (sort of), a thickener, gravy, biscuits (pretty close), cakes (pretty much), cookies, etc. EVERYTHING. That's not to say it's the best for any of those purposes - it's just the sort of median flour that you can make work for lots of different things.

This is not to slight the quality of KA flour in any way, shape or form. KA quality control and the consistency of their flours is great. If they say the protein content is 11.7%, that's what it is.

The GM AP ranges from around 9.5% protein to 10.5% protein. You're only likely to see it drop much below 10% in the south (land of biscuits), but the variation is nevertheless there. They won't even tell you the protein content up front, you have to go out and find people who have actually tested it (for real, not in non-equivalent types of "testing" done by the referenced blogger). Even if the blogger lucked out and got the GM AP at the top of it's usual range - roughly 10.5% - that still wouldn't be equivalent to an 11.7% flour!

A more meaningful test along the lines of what that blogger did would be to take KA AP flour and test it against something of roughly equivalent protein content. Say, for instance, the bread flour I get from Costco here, which is 11.6% protein. I wouldn't be surprised to see some difference, as the KA is made from all one sort of wheat (hard red winter) and the ConAgra flour is milled from a mixture of grains; but I doubt it would be objectively a whole lot different, except possibly for some specialty breads that are beyond my capability to bake anyway.

I say that because I HAVE used both flours, and while I prefer the KA because of the quality reasons listed above, I don't see enough of a difference for my uses to justify paying 5 times as much for it as for the Costco stuff.

reply by: BakerIrene on September 08, 2011 at 9:17 pm

I tested the following (remember I'm in Canada):

--King Arthur AP and King Arthur Bread Flour hand carried across the border

--"Five Roses" unbleached AP and white AP (12 grams protein per 100 grams)

--"Robin Hood" unbleached AP and white AP (4 grams protein per 30 grams = I think there was rounding up)

--"Selections" and "Equality" (generic labels) unbleached AP and "Selections" white and pastry flours. AP flours had 11.8 grams protein per 100 grams.

Results: All of the Canadian unbleached AP bake bread just about the same. KAF AP is softer, you have to mix the AP and Bread flour 1:1 to get the same as the Canadian flours.

I buy the "Selections" because it's a very consistent quality at half the price. "Robin Hood" was the most variable between bags and most expensive.

Where I had the unbleached and white versions from the same mill, the unbleached made better bread, and the white made better scones, muffins, pie crust.

I used to live in MA and I HATED "Gold Medal" after the stores brought in King Arthur. Before that, I used to bring flour from Canada on a regular basis. You can feel the difference as soon as you stick your fingers in the bag...

reply by: KitchenBarbarian aka Zen on September 09, 2011 at 4:08 am
KitchenBarbarian aka Zen

To my knowledge, Robin Hood (which we used to buy here all the time when I was a kid but which I haven't seen in years) was just regular ol' AP flour. Wouldn't be much good for making bread.

I don't know what process is most commonly used to bleach AP flours these days. I know when I was a kid we at least THOUGHT it was all bleached by chlorination. That process damages gluten, which is great if you want cake and not so great if you want bread.

For years bread flours were bleached via bromation. However this is falling out of favor. Bromation enhances gluten formation.

Now many mills are switching to a peroxidation process. This leaves gluten unaffected.

Even though a flour may have the same brand name, that doesn't mean it's the same mix of wheat (one bleached, the other unbleached). There are several manufacturers here in the US that use hard red winter wheat (as KA does) for their unbleached flours, but continue to use the more typical blend of different wheats for their bleached flours. It's the different wheats use that would affect gluten, not the bleaching process (excluding chlorination).

There is empirical evidence that shows this to be true which has been referenced in prior threads on this issue.

So if there's an advantage to buying "unbleached flour" - and I submit that in most cases there is not - it's that you've got a shot at getting a better quality, more consistent wheat.

I forget off hand which major flour manufacturer (or packager, I guess I should say, since they all buy their flour from mills which they might or might not also own) - anyway, I forget who it is whose unbleached bread flour is made from hard red winter wheat like KA. Pillsbury? GM? Can't remember, but it's in one of my old postings. It's a national brand. But the rest of their flours are all the typical blended wheat varieties.

Maybe someday I'll find somewhere to buy KA in 25 lb bags - that might make it more cost effective. I'd gladly pay double what I pay at Costco, but 5 times as much is just TOO much. Wish my Costco would carry it - some do, but not this one.

reply by: kidpizza on September 09, 2011 at 12:30 pm

Regarding the last paragraph of your post dated today. I would like to ask you which state do you live in & which large city are you close to ???

Have a nice day.


reply by: KitchenBarbarian aka Zen on September 09, 2011 at 1:01 pm
KitchenBarbarian aka Zen

Thanks, KP, but I've checked with all the places KA lists in the area that carry KA products and none carry the 25 or 50lb bags of flour. The nearest large city is TOO FAR (my son's constant complaint, if it's 15 mins its a long drive for him). I don't drive these days - even if I do get my driver's license again (it lapsed during my illness) it's probably farther than I should be driving anymore. I think it'd be an hour or so one way to drive over there to the state capital. I know FOR SURE I wouldn't try it without a GPS, if I were to drive myself. Another sign that I shouldn't be driving, I'm sure, is the ease with which I can lose myself in any situation.

Oh how I long for the days when I could hop in the car after work Friday evening, drive all night to get to a ski resort, ski all day, sleep in a cheap hotel, get up and ski until dark (after dark if they were lighting the trails), get BACK in the car and drive all night to get home, then go to work in the morning!

Heck, I'd settle for being able to throw more than a couple pounds of clay on the potter's wheel at this point. One small bowl and I'm pretty well wiped out for the rest of the day.