Real Baking with Rose Levy Beranbaum

Yes, she does! It is a very big deal to us here in the UK, who can't get access to any bleached flour.
Her results are fantastic!

Posted by: Melinda Pickworth | November 6, 2007 9:28 AM #

A v. interesting comment has just been posted to my blog re improved texture results after microwaving even cake flour (see comments on my latest post). Is this something that anyone else has tried (or would someone with access to cake flour be willing to try this for me ...?)?

Posted by: Kate | November 7, 2007 3:03 AM #

I hope you don't mind me posting this here too, as well as on my own blog, Rose. There has been the suggestion of creating a clear formula for bakers to follow, including flour type, quantities, etc. I think this would be an excellent next step.

Perhaps we could have a co-ordinated, international testing effort as many flours will be specific to different countries …

If anyone is interested in taking part in something like this (or has a better idea or even experience in developing baking formulae), perhaps you could send me an email - amerrierworld at googlemail dot com - thanks

Posted by: Kate | November 7, 2007 4:17 AM #

I have tried microwave the flour. My microwave is 900W and after 2 minutes on the highest power, the flour seemed to be cooked,some sticking to the bottom of the pyrex plate and get into large lumps. I have to sift it and a lot cannot pass through and I have to add more flour to the required amount.Is that so ? or should I use lower power?

Posted by: cindy Chiu | November 8, 2007 11:39 PM #

I have a high power microwave also. I put the flour in for 1.5 mins. , take it out and stir it about a bit then put it back in for another 1.5 mins. It is best to put in more flour than the recipe says as you lose some weight with the moisture lost, and you also do get the flour lumping together so it needs sieving well . I f this does not help try lower power or less time , say 30 secs. less to see if that helps. I have made one very successful cake using microwaved flour, the one I made last had a nice texture but didn't rise as much as I would have liked. I'm wondering about the differences in baking powder between the countries also, could this affect results?

Posted by: Jeannette | November 9, 2007 3:48 AM #

Yes, this is something I've been thinking about recently. My microwave is 750W, so 'high' for me is quite a bit less than 'high' for others. I'm hoping to be able to present some clear guidelines after testing which will include a breakdown of how many minutes to microwave the flour at different levels of W (750/850/950 etc). It would be helpful to get a rough idea for now of the sorts of W that people typically have (I use my microwave mainly to defrost baby purees I've prepared and frozen, so I'm not really your 'typical' microwave user!)

Posted by: Kate | November 9, 2007 4:15 AM #

Yes, this is something I've been thinking about recently. My microwave is 750W, so 'high' for me is quite a bit less than 'high' for others. I'm hoping to be able to present some clear guidelines after testing which will include a breakdown of how many minutes to microwave the flour at different levels of W (750/850/950 etc). It would be helpful to get a rough idea for now of the sorts of W that people typically have (I use my microwave mainly to defrost baby purees I've prepared and frozen, so I'm not really your 'typical' microwave user!)

Posted by: Kate | November 9, 2007 4:17 AM #

If one doesn't have a microwave, would it be possible to achieve similar results by, for example, baking the flour in a warm oven?

Posted by: Beverly | November 9, 2007 8:55 PM #

From what I understand about it, yes, but it would take a substantially longer time (I've read of this being done for 10 hours to 2 weeks!). Perhaps the microwave will become the new KitchenAid (or Kenwood, for those of us in the UK)!

Posted by: Kate | November 10, 2007 2:56 AM #

If you have a thermometer, this approach seemed to work well today and is easier than guessing blind at microwave times and powers ...

http://amerrierworld.wordpress.com/2007/11/10/getting-warm/

Posted by: Kate | November 10, 2007 5:00 PM #

Now there's some daylight again, I've added a photo to the above blog post to illustrate the results :-)

Posted by: Kate | November 11, 2007 4:30 AM #

I have two quick questions:

1) How does bleaching allow the flour to gelatanize?

2) Is there a good rule on when you want bleached flour and when you want unbleached?

3) In bleached flour, it would seem like you're eating some bleach. That sounds unhealthy. Are we eating any bleach from this, and if not, why not?

4) Does anyone have any tips on how long to cook a frozen pie vs. a normal one? My parents made a bunch of apple pies for Thanksgiving and froze them, and don't know what the best method of cooking them would be.

Thanks for the help.

Posted by: Richard | November 11, 2007 5:59 AM #

Rose, thanks for the help, and for pointing me to your crossing the Atlantic post.

What I'm getting from this is that bleached flour will generally make a lighter product then unbleached. Therefore, if you want a denser bread, you would go with unbleached bread flour, which would also have the benefit of having more gluten to strengthen the bread's structure.

If using bleached bread flour (I can't recall if I've seen this; I think I have), you would need to add more flour or some vital wheat gluten to compensate for the gluten loss from bleaching.

This also explains why I don't ever find unbleached cake flour.

This raises the question of what makes better pastry flour; I'll have to experiment with pastry flour made using bleached AP vs unbleached AP mixed in with the cake flour (I seem to have a hard time coming by pastry flour).

Thanks again; that helped a lot.

Posted by: Richard | November 11, 2007 1:56 PM #

i wanted to let you know that the kate flour worked brilliantly for me. in fact it has stopped me giving my copy of the cake bible to a charity shop. it was a gift from friends in the states and everything i tried was disappointing so i was about to give it away. only last week i made the domingo cake, it was solid. today i followed the directions on kate's blog to make kate flour. the same flour, a totally transformed cake!!! it's incredible.

Rose, without overstating the point, isn't this something fairly huge for you, i mean your book now has viable sales outside the states? will you include kate flour in your next book or is it too late for that?

Posted by: Sarah | November 12, 2007 4:14 PM #

I am trying to make pastry type crust for samosas and the unbleached AP Flour wont solidify...stays crumbly..whats the problem?

Posted by: Bob | November 14, 2007 1:16 PM #

Hi Kate/Rose- can i make Kate-flour(in bulk) now and use later, or is it necessary to process the flour immediately before baking?

Posted by: nushera | November 14, 2007 6:30 PM #

Thanks, Rose.

Posted by: nushera | November 14, 2007 11:53 PM #

From a safety point of view, I really wouldn't try microwaving any more than about 10 oz of flour at one go. It gets very hot! (plus, it would make the bed deeper than 2cms ... unless you have a super-large microwave, of course!).

Posted by: Kate | November 15, 2007 8:55 AM #

I use unbleached flour all the time for all my baking needs and have never had a problem with it. I won't use bleached flour, since that's just what it is, bleached, with chlorine.

Posted by: D L | December 3, 2007 11:49 PM #

well, the "problem" thing may be relative and vary from person to person. even with Rose's recipe for Genoise Classique or French Genoise i once got such a crumbly output .
http://www.apona-bd.com/photos/rcache/c20b9c6d476f0328cc92eed8d6529ff0.jpg
chosing a lower-protien flour and then switching to Kate Flour has changed the result. hope to post a better-result-photo later this month.

Posted by: nushera | December 4, 2007 12:55 AM #

I am trying to make Russian Rye Bread. My bread turns out very heavy and dry. Need Help. So you have a receipe. Sandy

Posted by: Sandra Bell | December 4, 2007 8:02 AM #

I just came across this via a post at Daring Bakers. I've been using Gold Medal unbleached AP for all baking because I wanted to avoid the chemicals, and I guess this is why my cakes were never as light as I would like. They weren't lumpy or chewy, just dense. My question is, can I do the Kate treatment on the Gold Medal unbleached i buy?

Posted by: aisha | January 3, 2008 2:31 PM #

I'd guess yes, it would work. It would be great if you could try it and let us know :-)

Posted by: Kate | January 4, 2008 9:03 AM #

I've just put in a pair of 9 inch cakes in the oven, one with treated unbleached AP flour, the other untreated. *fingers crossed*

Posted by: aisha | January 7, 2008 3:09 PM #

well, the results are a bit disappointing. there's no real difference! both came out about 1.25 inches. and stayed that way. i want to say the heated flour's crumb was a little finer, but barely. i had heated 4 oz of flour 3 times, for 1 minute each.... maybe i should have done it a little longer. i never saw any vapor, though the flour did clump a bit.

Posted by: aisha | January 7, 2008 4:23 PM #

aah, i went back to kate's site and saw the helpful hint about measure the flour's temp. i wish i had been more thorough in my background reading. well, i'll give it another shot in a few days.

Posted by: aisha | January 7, 2008 4:41 PM #

Here are the steps, aisha (and anyone else, for clarification). I found that the temperature thing was very important - in fact, as I hope you too will find aisha, it made the whole difference to the success (or otherwise) of the flour ...

Turning Unbleached Flour into Kate Flour: 10 Steps

1. Weigh out 280g/10 oz of the flour and place it onto a microwave-safe plate.
2. Spread the flour on the plate to give a bed depth of 18 to 20 mm.
3. Microwave the flour for 1 minute. Remove from the microwave and use a probe thermometer to take and record a temperature reading. Break up any lumps with a fork.
4. Repeat step 3 until you obtain a temperature reading of at least 130 degrees C.
5. Allow the flour to cool to room temperature.
6. Sieve the flour and discard any residue.
7. Spoon the flour into a 250ml measuring cup and level the top. Weigh this flour and record the weight.
8. For flours with a 9% or more protein content and when cake flour is required, substitute 2 tablespoons of this cup with 2 tablespoons of cornflour/cornstarch. Do this by calculating and then removing 1/8 of the weight of the cup of flour. Replace this with 1/2 oz (14g) of cornflour.
9. Make up a second part of kate flour according to the weights of flour and cornflour obtained in steps 7 and 8.
10. Place both parts of kate flour in a large bowl and whisk to combine thoroughly.

Posted by: Kate | January 8, 2008 1:25 PM #

thanks much kate, i've heated up another batch of flour and i'll try again tomorrow.

Posted by: aisha | January 9, 2008 11:38 PM #

I have done two tests with Kate flour, and I posted results to Kate's blog with pictures available.

I made two chocolate chip cookies and noticed that the pillsbury bleached flour and the kate flour didn't brown as quickly, and the unbleached ones may have spready slightly more, but differences were fairly subtle. This is in contrast to Kate's results which showed a significant improvement in the cookies from the treated flour.

For the cakes I made two cakes and coming out of the oven there was an obvious difference: the unbleached flour cake fell in the center. But when it came time to eat the cakes the difference was again fairly subtle. I couldn't really pick a favorite.

Kate asked me to repeat the tests with the same cookie recipe she used and with the gold medal unbleached flour adjusted for protein content.

But at this point, I get confused. Kate thought that the gold medal unbleached flour was 10% protein and the cake flour 6% protein. If that is true, I calculated how much starch to add in order to reduce the protein content from 10% to 6% and it's a huge amount, not the paltry 1/8 cup per cup that is often advised. Instead, I need to use something like 55% flour and 45% starch. I don't think I've ever seen a ratio like that recommended.

I also have another point of confusion. I thought that only cake flour was chlorine bleached and other bleached flour was bleached with peroxide or some other agent. I also got the impression that the chlorine bleaching had a different effect that was particularly important for cakes. Is this true?

Is the difference in my cookies due to protein content or due to the treatment (bleaching/heating)?

Posted by: adrian | February 14, 2008 9:24 AM #

Well, if I'm trying to drop from 10% to 8% I should use 80% flour and 20% starch which is a bit more than the recommended amount, but not so extreme.

Is chlorine bleaching better simply because it's harsher and damages the starches more? I vaguely recall reading that the chlorine treatment left cake flour slightly acidic and that this caused the cake to set faster (hence giving a finer texture).

Posted by: Anonymous | February 14, 2008 9:44 AM #

Does that mean it would make sense to add some cream of tartar to the flour to acidify it? (Or to increase acid in the recipe some other way?)

Of course I will use weight. The plan is to make the downy yellow butter cake from the cake bible with kate flour that has been protein adjusted and with unbleached flour that has been protein adjusted but not microwaved. (Hmmm. Maybe I need a 3rd cake made with unmodified unbleached flour too...?)

Kate's procedure on her blog seems a little overcomplicated. She says to "[S]ubstitute 2 tablespoons of this cup with 2 tablespoons of cornflour/cornstarch. Do this by calculating and then removing 1/8 of the weight of the cup of flour. Replace this with 1/2 oz (14g) of cornflour." It seems that she cooks by weight but makes this diversion into volume measurement to calculate the starch replacement.

It seems more sensible to me to simply take the desired weight of flour and replace 20% of it by weight with starch. I suppose for best results this should be done before microwaving, though I'm not sure I want to bother with that.

Posted by: adrian | February 14, 2008 9:58 AM #

I was under the impression that baking by volume was an American practice and that in Europe everybody baked by weight. Am I mistaken? The text on her blog is written as if you're going to bake by weight.

(I wrote to Kate about the substitution, but haven't heard back.)

Posted by: adrian | February 14, 2008 10:18 AM #

Hi Adrian - Sorry I haven't got back to you before now - I've just taken over as Chair of our local Pre-School and have found myself with not only the regular Chair duties to perform but also with initiating and co-ordinating a community effort to raise £200,000 for a new Pre-School building!

About the weight/volume thing - when I first tried to formulate a way of reducing the protein content with cornflour, I only had as a guide the American "Substitute 1/8 cup flour with 1/8 cup cornflour". However, I wanted to be more precise, especially when it came to involving different people around the world in testing the flour. The problem as I saw it then was that there was no standard weight for a cup of flour, so I couldn't simply convert the volume instructions into weight instructions. The only way I could think of finding out what a cup of flour weighed for each specific flour after microwaving was to actually get a cup, fill it with flour and then weigh that flour. Hence my rather convoluted instructions.

However, after further discussion with Rose, I understand that the 7:1 flour/cornflour ratio can equally apply to weight (remember that I had only seen this before expressed as volume). So (and I mean to update this on my blog, too), I now microwave my flour then make it up into parts of 3 1/2 oz flour + 1/2 oz cornflour - no cups involved :-)

Does that help explain my ideas any? (PS - I confess, I'm not a natural mathematician ;-) !).

Posted by: Kate | February 14, 2008 10:52 AM #

That definitely sounds like it could take up some time. (So, how much can you raise with a bake sale where the products are all baked in slightly different ways, some with one kind of flour, some with another....:)

I could see where you came from in formulating your substitution. It just seemed to me like a misguided approach because first of all, it assumes that the substitution of 1/8 cup of cornflour actually had any justification behind it. My guess is that it didn't, really. So trying to figure out how to "exactly" replicate this substitution in weight when there was nothing exact to start with seems kind of pointless.

Protein contents are calculated on a per mass basis. I found a claim that gold medal flour is 10.5% protein, and King Arthur 11.7%. (There was no indication of whether the bleached and unbleached gold medal are different.)

If you use a substitition of 3.5 oz flour and 0.5 oz of starch and you start with something that is 10.5% protein the result will be 9.2% protein. (This is 10.5 x 7/8.) If we want to get from 10.5% down to 8% then we need to use twice as much starch (3 oz flour + 1 oz starch). (And you can calculate the protein content as 10.5 x 3/4). And somebody who was using King Arthur would need to use even more starch (about 1/3), so it would be 2.75 oz flour and 1.25 oz starch. (The protein content would be 11.7 x 2/3.)

Anyway, the conclusion is that the substitution of 1/8 part starch (cornflour) doesn't seem adequate, at least with my flour, to get down to cake flour territory. Is there some reason not to use a mix that is 25% starch?

Lastly, if the value of microwaving the flour is that it alters the starch, surely the benefit will be increased if that extra starch is in the microwave with the flour.

Posted by: adrian | February 14, 2008 11:19 AM #

You're very right :-) I'm not convinced however that the protein content is actually the major contributing factor in the success of this flour. I suspect that more is going on in the microwave than meets the eye. I tried to persuade someone with an electron microscope to have a peek down it at some microwaved flour for me, but the cost was prohibitive. There's a paper by some scientists in Japan (I'll look up the details later) that shows electron-microscope photos of starch molecules in maize after microwaving. The effect is stunning! - the surface of the starch molecules has deep potholes after microwaving.
I haven't tried microwaving the cornflour too ... sounds like a good next move to me :-)

Posted by: Kate | February 14, 2008 11:49 AM #

If the protein content isn't really a big deal then I shouldn't expect to get different results with reduced protein content.

When I did this before, there were a few places where the flour browned. What happens if you microwave for too long? (I tried not to use the affected flour.)

Posted by: adrian | February 14, 2008 1:13 PM #

I did a test flour cake bake for Kate using a flour from Shipton Mill here in England. The gluten protein was 8.5%. I did not do the cornflower substitution.
The cake was absolutely lovely. It would not have been as nice without the microwaving of the flour first.
I found I did not get any burned flour bits if I did incremental microwaving and stirred between blasts. I have made many disaster cakes trying different emergency substitutions for cake flour. Nothing has had the results that the microwave heat treating has produced. You can look at my blog for results of the cakes. It is listed under 'testing 3 flours'.Cheers Adrian.

Posted by: Melinda Pickworth | February 14, 2008 2:01 PM #

I did my own experiments in the interest of scientific curiosity, as I have no problems getting bleached flour. And I didn't get the same results as many others have. So I wonder why? Did I do something different? Is my flour different?

I did incremental microwaving. I can't remember if I stirred. But I do recall that I took the temperature and it was still well below the target temp and then I put it back in and the next time I took it out the temperature was far above the target temp.

Posted by: adrian | February 14, 2008 2:06 PM #

I think the protein content is a deal - it's just that it's not such a big one ;-)

The first cake I made with microwaved flour - see http://amerrierworld.wordpress.com/2007/10/28/a-question-of-flour/ - was a gigantic improvement on the cakes I made with the same flour, unmicrowaved. The cake I made with the protein content lowered - see http://amerrierworld.wordpress.com/2007/10/30/more-questions-of-flour/ - was better than the cake I made without lowering the protein content ... but not by such a huge amount. I can see what you're saying, though ... why would I ask you to repeat the yellow butter cake, lowering the protein content? It's just that I don't have access to the flours you are using - I tend to find that lowering the protein content makes a more significant difference when the flour I'm using is a mix of soft and hard wheats and is not finely milled (ie UK plain flour rather than 00 Grade flour). Perhaps you would notice this too ... ?? I don't know until you try it ;-)

Like Melinda, I've found that the flour doesn't brown if you microwave it in short bursts, stirring in between.

Posted by: Kate | February 14, 2008 2:12 PM #

Wasn't Woody already going to be trying that, Rose? ;-)

(I can't find the email where we talked about that right now, but I think I sent you a paper suggesting that bleached cake flour was indeed improved by heat-treatment)

Posted by: Kate | February 14, 2008 2:24 PM #

Adrian wrote:
"Anyway, the conclusion is that the substitution of 1/8 part starch (cornflour) doesn't seem adequate, at least with my flour, to get down to cake flour territory."

Bleaching reduces the protein content of flour ... no? If heat-treatment also reduces the protein content (?), then it wouldn't be a simple calculation on the basis of the % protein before treatment to get down to the level of the protein of cake flour.

Posted by: Kate | February 15, 2008 4:32 PM #

I'm pretty sure that bleaching does NOT reduce the protein content of flour. Neither does heat treatment. (When you cook things the protein does not transform into fats or carbohydrates.)

The manufacturers of flour tend to formulate bleached flours to have less protein (using more soft wheat) because they expect you to use them for cakes and pastries, whereas unbleached flours are expected to be used for bread and are hence formulated to have more protein.

Posted by: adrian | February 18, 2008 8:01 AM #

I can believe that bleaching weakens the gluten. Would heating weaken the gluten? I would guess no, but maybe it could.

Posted by: Anonymous | February 19, 2008 9:39 AM #

The cake made with heat treated and bleached flour was LOWER than bleached and not treated cake? Is that good?

What is the relationship between protein content and rise? (In my own test the treated flour cake was higher than the untreated flour cake.)

Posted by: Anonymous | February 19, 2008 9:48 AM #

I see. Nothing to do with protein content. But definitely interesting.

Posted by: adrian | February 19, 2008 10:16 AM #

So the idea is that bleaching lowers the protein efficacy and that's good, to a point, but following it up with heat treatment lowers it even more and that's not good?

What about the effects of these treatments on the starches?

Posted by: adrian | February 19, 2008 10:31 AM #

Kate, I've met with my friend Lorraine from Luscious Lorraine (Palm Dessert, California). She is an organic baker and chef, and it was interesting to chat about your discovery. I hope heat treated flour qualifies for organic since I believe bleached flour does not.

Posted by: Hector | February 19, 2008 11:38 AM #

It might be worthwhile finding out if any commercially heat-treated flours are available where you are, Hector. It would be interesting to see how a commercially heat-treated flour compares with a home heat-treated flour ...

Posted by: Kate | February 20, 2008 3:11 AM #

Hi, I'm trying to think of a way to clarify this whole protein/gluten/bleaching/heat treating thing...let's see if I can say something that will help.

I think the most important point is that the protein content of flour is NOT the same thing as its gluten-forming potential. But, people often use the protein content as a "rough guide" to the gluten-forming potential.

"Protein" is a very general term -- all sorts of molecules qualify as proteins and all sorts of things contain them. Wheat contains two special proteins, glutenin and gliadin, that combine to make this magical thing called gluten that gives bread such a great texture. The important thing is that wheat flours that are higher in protein in general also usually do contain more of the special gluten-forming proteins. (I think there may be certain breeds of wheat that are an exception to this rule -- but for the ones that are usually used for standard flour, it's pretty much true.)

So, protein content of flour is an approximate guide to how much gluten it MIGHT possibly form, under the right conditions. But there are complications.

Gluten is made when two proteins in the flour, glutenin and gliadin, link up with each other in the presence of water and agitation. Bleaching and heat treatment must somehow make chemical changes to these proteins. They are still present in the flour (the protein content is the same), but somehow it is harder for them to join up to form gluten (so the gluten-forming potential is lower).

Does that help any, or does it just make everything more confusing?

Here's some information:
http://en.wikipedia.org/wiki/Gluten

Posted by: Barbara A. | February 20, 2008 10:10 PM #

I understand the point about treatment of flour (possibly) reducing gluten formation.

But if the goal is simply to reduce gluten formation, why not just bake with pure starch, or add starch to the flour? That's easier than bleaching or heat treating. If flour treatment worked by simply reducing gluten formation then we could get the same result by using starch instead of flour. Something else must be going on, presumably having to do with the gelatinization of the starch referred to above. And that something else is presumably what's important. (I mentioned above the acidification that chlorine bleaching causes.)

I expect that we want some gluten formation in a cake to give it structure. If I understand correctly, Rose thought that the treated bleached flour performed worse (lower rise) because of impaired gluten formation resulting from the double treatment.

Posted by: adrian | February 21, 2008 11:07 AM #

As far as I understand it Adrian, bleaching and heat-treatment accelerate the natural processes of aging in flour. Oxidation of carotenoid pigments leads to protein denaturation. This promotes gelatinization of the starch granules, thereby increasing their absorption properties - which improves the flour's baking performance.

Another possible factor to consider is the way in which both chemical and heat processes attack the surface of the starch molecules and roughen them. Photos of starch molecules after microwaving suggest that the speed of agitation literally blasts them apart. The authors of this study write that "the data showed that rearrangements restricted to sections of the starch molecules resulted in the formation of new crystallites of different stabilities and led to a more ordered crystalline array." - see http://tinyurl.com/28tve7

Hope that helps ...

Posted by: Kate | February 21, 2008 12:03 PM #

A rough surface would be important when it comes to holding butter in suspension.

Posted by: Kate | February 21, 2008 12:16 PM #

Rose, can you get an electron microscope of Kate's microwaved flour? It will be interesting to see the physical shapes of the flour particles, as I suspect that microwaving flour must expand the starch granules into Wondra like particles like microwaving popcorn!

It will be magical if all we need to stock is a high protein unbleached bread flour, and with the microwave we can convert it into Kate's gold for cakes and for pastry!