Kate Flour
From Cake Flour to Kate Flour
Kate flour has been created as a replacement for bleached flour in countries where the bleaching of flour is prohibited. In these places, which include the countries of Australasia and the EU, bakeries and other businesses may have the opportunity to source heat-treated flour as a viable and successful alternative to bleached flour for use in high-ratio cake recipes. The home-baker is not so lucky.
Until commercial, heat-treated flour is made available to the individual consumer for personal use, kate flour is perhaps the sole means by which home-bakers in these countries can recreate and appreciate the advantageous properties of bleached flour in their own kitchen.
The Story of Kate Flour
The creation and development of kate flour can be followed in the following blog posts from Autumn, 2007:
A Question of Flour, in which the microwaving of flour was introduced;
More Questions of Flour, in which the protein content was cut;
Water, Water Everywhere, in which the moisture content was considered;
Getting Warm, in which the thermometer made its first appearance;
… with additional refinements in Spring, 2008:
Finding the X Factor, in which xanthan gum improves the viscosity;
Colour or Crumb, where self-raising flour provided the best-yet results;
… and even further refinements in Winter, 2008:
Treatment of Choice, in which the toasting problem is resolved and the conventional oven joins the fun.
Turning Unbleached Flour into Kate Flour: 10 Steps
1. Weigh out 280g/10 oz of the flour and place it in a microwave-safe, flat-bottomed bowl.
2. Spread the flour in the bowl to give a bed depth of 18 to 20 mm.
3. Microwave the flour for 10 seconds then open the door and stir with a fork to prevent the flour from browning. Continue to microwave and stir the flour at 10-second intervals.
4. After about 3 minutes of total microwaving time use a probe thermometer to take and record a temperature reading. Repeat microwaving and stirring at 10-second intervals 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. To re-hydrate the flour, spread it on a baking tray. Place it in a cold oven (with the oven turned off). Pour boiling water into a dish placed on the floor of the oven. Close the oven door and leave for 5 minutes. Replace the water in the bowl with boiling water and leave for a further 5 minutes.
8. For flours with a 9% or more protein content and when cake flour is required, weigh out the amount of flour needed for the recipe and substitute 1/8 of this weight with cornflour.
9. Add 1/4 teaspoon of xanthan gum (1/8 teaspoon for recipes using up to 5 oz flour) to the flour needed for the recipe.
10. Whisk to combine thoroughly.
Trackbacks & Pingbacks
- Lemon Cake and Cauliflower « A Merrier World
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- TWD- Chocolate-Chocolate Cupcakes « Andrea In The Kitchen
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Hi Kate,
I found microwaving the flour a tricky business. Has anyone tried using an oven ?
Many thanks,
Allen
yes there is a wide available literature on flour heating using oven. Typically we have to evenly spread the flour on the pan (0.5 cm) with/without the aluminum film. Preheat your oven to 120 C and heat the flour for about 30 min to 2 hrs. For pancakes you can use 2 hrs and for bread use 30 min. Since it takes longer, usually people prefer microwave. However, it is important not to have flour dust while microwaving since it can cause a blast (minor). Hope this helps.
I haven’t tried using an oven … some sources (see the patents I reference) suggest that this is a possible alternative but is largely impractical because of the length of time it takes to achieve similar results. However, it appears that the speed of microwaving literally attacks the surface of the starch molecules and ruptures them. I wouldn’t have thought that this would also happen in an oven as it would be a much slower process. I guess the only way to find out is to try it!
Hi Kate,
I’ve just found your blog (someone linked you in a comment on Mark Bittman’s blog over at the New York Times). I’m absolutely amazed at your discoveries!
I’ve always just substituted plain flour for cake flour, or at most a mixture of plain and corn flour, and never suspected that it would make such a difference. When a cake was particularly stodgy I blamed myself, or the recipe (usually the latter).
I’m in awe of your persistence in testing and refining your kate flour method, and extremely grateful that you documented and shared it in such detail.
I just moved from the UK to Cyprus, where the flour selection is (1) plain (wheat) flour; or (2) “village flour” made from durum wheat. No indication of protein content or anything else. I’ll definitely be making up some kate flour of my own asap!
Kate, I discovered your blog through Rose LB’s website which I resorted to in a fit of frustration after attempting to make her “Downy Yellow Butter Cake”. I am an American living in Mid-Sussex and have been stumbling along using my American recipes with U.K. ingredients with varying results. Your and Rose Beranbaum’s information on flours have been a real revelation and I salute your efforts to bring lightness to world cake-baking.
A couple of questions:
If I want to use my American recipes which call for “all-purpose flour” as opposed to cake flour or a recipe that calls for pastry flour what do I do or use here in the U.K?
Rose LB mentions that baking powder is very different and, indeed, checking the ingredients they certainly are–does that seem to make a difference when using her recipes here with U.K. baking powder?
And finally, is there a good online source for baking ingredients here in the U.K?
Thanks so much for everything I’ve learned so far.
Good luck with your kate flour, Hazel
No-one so far (AFAIK) has tested flours in Cyprus, so I’d love to hear about your results.
Thanks for your comments, Bernardean
I use Plain Flour (I like Dove’s Farm, but McDougall’s or Be-Ro are good too) for All-Purpose. If the recipe requires bleached all-purpose (cookies … pastry?), I microwave the flour but don’t cut the protein with cornflour/cornstarch. As far as baking powder goes … my cross-atlantic experiments with Rose and Woody (more about this later!) certainly suggest that something apart from differences in flour causes differences in cakes made with the same recipe. My guess is that it’s the baking powder … but the (tentatively) good news is that UK baking powder gives better results with kate flour than US baking powder.
Thanks for the wonderful post. I have following inputs
1. Flour heating mainly came into picture to cut down the chlorine levels in the flour.
2. If you are using chlorinated flour, heating of flour could cause detrimental effects – one that you would immediately notice is the viscosity of the batter. It would be hard to pour the batter from the mixing bowl to the cake bowl.
3. Heating flour makes the starch more hydrophilic (water hating) and helps it bind more oil as well as stabilize the gas bubbles (just like stronger film surrounding the bubbles). This is very different from baking powder. Which basically acts to produce air cells. Since you are having better air cell stability using “kate flour” the amount of baking powder can be reduced. Try 1/2 or 1/3 of the original recipe.
4. If you are making pudding try heating potato flour to have a cohesive paste after heating. Potato flour has different starch composition as compared to corn or wheat.
Hope this helps.
Hi Kate. I’m so glad I found your site. I’m an American living in Tasmania, and I’ve been fighting with the flour here (what a mess!) Nothing ever bakes the way I would expect it to. I still haven’t conquered an open crumb Italian loaf…
What is the chemical makeup of English baking powder (since it works better with Kate flour)? I import US baking powder for some uses. But if local stuff works better, I’ll use it.
Thanks.
Hi Andrea,
The jury’s still out on the baking powder question, but it’s probably worthwhile trying your local brand. I’m using Super Cook baking powder at the moment, but I also use Fiddes Payne. The Super Cook bp states: “Rice flour + Raising Agents – Disodium diphosphate, Sodium hydrogen carbonate”
I’m pleased you’re having better results with kate flour
HTH
Hi again Kate, it’s been awhile since I posted last, but I only got round to testing my flour yesterday. I did two batches. The first batch I overcooked, it ended up 145C with a distinct smoky smell and some browner patches in the flour, so I did a second batch.
My results:
Mitsides Plain Flour (Cyprus)
8 minutes at 800W
1 cup = 123g
Mitsides flour page: http://www.mitsidesgroup.com/main/main.asp?cm=0203
Protein content isn’t specified on the flour packet, and my email to the producer has yet to be answered, so I didn’t add any cornflour.
Used the flour to bake half a recipe of the wedding cake base from Baking with Julia, but substituted 1/4 cocoa powder to make it chocolate flavour. Unfortunately didn’t have time to do a side-by-side comparison with untreated flour, but I hope to do it today.
Again, thank you for sharing this idea!
I read your previous posts with regards to the history of kate flour and it really is amazing. I got here because I was reading from Rose’s blog about cake flour and if I can successfully make my own kate flour here it would definitely help me in terms of costs of the ingredients because commercial cake flour in the supermarkets in my country are really expensive.
Hi, And thanks a million for this awsome discovery. I am in Norway and just starting up my weddingcake business. I love Rose’s TCB and wanted to use that as my base. BUT all my cakes were dense, soggy and too sweet.
When I read this I see some hope!!!
However, I am not sure i understood step nine. Do you want me to make an other batch of microwaved flour and the repeat step 7-8?? Or is the 280 gr of flour enough to repeat the process twice and then mix????
Hi Sugar – I wrote the instructions based on my own experiences of microwaving flour in my own microwave. I found that it was best to microwave 10 oz at a time – any less, and the bed depth was too little (I even melted through a plastic plate once by putting too little flour on it! That’s why I use pyrex now) … any more and the bed depth was too great. If you have a bigger plate and microwave, then I’d guess you could microwave more in one go.
You need to aim for a bed depth of about 2cms. Depending on your flour and the power of your microwave, it helps to microwave in even shorter bursts than I suggested above. I sometimes microwave for only 20 to 30 seconds at a time to avoid the flour browning. The best way is to go by the temperature on a thermometer – stop microwaving when it reaches 130 degrees C.
I haven’t had any problems storing this flour once it has cooled, so you can make up enough for several cakes. Rather than substituting with cornflour by volume as I suggest above, it’s easier and more exact to substitute by weight. Sieve the microwaved flour to remove the lumps, then weigh it. If you started with a higher-protein flour, you’ll need to add more cornflour than if you started with a lower-protein flour. It’s best to aim for a final protein content of about 7-8% Usually, this means I add 1 0z of cornflour for every 4 oz of microwaved flour. If you have some, you could also try adding 1/4 tsp xanthan gum to every 4 oz flour. When you’ve finally got everything together in one large bowl, give it a good whisk to combine everything evenly!
Hope that helps – and good luck with your wedding cake business!
I use proprietory gluten-free flour with xanthan gum, could I use your technique with non-gluten flour (rye; rice etc) or are they already refined?
I’ve never tried gluten-free baking, Dennis, so I really don’t know what it’s about … but I wouldn’t have thought that microwaving non-gluten flour would have any benefit for the sorts of recipes you will be using. Do let me know if you find out that I’m wrong!!
Dear Kate,a few more questions,please. After microvawing the flour ,how much do you put in the oven-what is left of 280gr.?And how much water do you pour in the tray,or it does not matter?I also baked quite a lot using Kates flour,but always encountered one problem-the cakes are extremely fragile and easely fall apart?Is it normal or is it my fault?
Hi Tania
but I usually spread all of the flour I’ve microwaved onto a large baking tray. I pour the hot water into a pyrex bowl (it makes the procedure slightly less sloppy than pouring it into a baking tray, which I originally used) on the shelf below the flour. It doesn’t really matter how much water you use, as long as there’s enough to generate some steam. I ususally re-fill the bowl a couple of times, shutting the oven door after each refill to ’steam’ the flour as much as possible.
My re-hydration technique is slightly under-refined at the moment
re cakes falling apart – when you take them out of the oven, are you leaving the cakes for long enough (10 mins) in the pans before turning them out to cool? They can crumble easily if you try to turn them out too soon, I find. Hope that helps …
Dear Kate,my husband recently brought bleached flour from America.I baked and experimented,but would like to share my thoughts with you.If you are interested,then e-mail please.
Hi Kate, your flour experiments have been extremely exciting to read. I have access to bleached all purpose flour (it’s actually hard to find unbleached all purpose flour where I live), but I was wondering if you knew if microwaving that would make a difference. I guess what I’m asking is can bleached all purpose flour substitute for cake flour better when microwaved? I always read about adding corn starch to all purpose flour to substitute for cake flour, but I’ve never tried that because I was afraid the cornstarch would suck up all the liquid and turn the cake dry (not sure if that actually happens, just a thought). Whenever I do sub cake flour for all purpose, I just subtract 2 tablespoons instead to match the lower protein content.
Hi Steph
There are sources that suggest that the microwave-treatment of bleached flour gives improved results, but I’ve never actually tried it. I really would advise that you are cautious if you do give it a go – when Woody (Rose’s tester) microwaved some cake flour in an experiment for me, it caught fire in the microwave! I don’t know whether this was caused by the bleaching of the flour or by the extremely fine size of the flour particles, but I would certainly be careful about microwaving bleached all-purpose flour. I haven’t found that adding cornflour/cornstarch in ‘kate flour’ preparations results in a dry cake though, so I’d imagine that it will give equally good results when mixed with all-purpose flour to lower the protein. You could give it a go to see if you notice any differences.
I hope that helps
.
The catching of flour on fire is a perfect example of uncontrolled power settings on the microwave. The recommendations that are given in your original blog are excellent at 80% power settings. The observing of fire could also be due to over heating of flour. According to the original patent (Gusek, 1995) the flour has to be dried to about 2% moisture (db).
One simple way of monitoring the moisture loss of flour is by weighing. Since your original flour contains ~13% moisture and you are drying it to ~2% moisture you will be losing 12 gms for every 100gms of flour. So when you use 280gm you will be losing around 30-33gms of the original weight. However, if you go above this charring of the flour followed by fire is inevitable.
Also, other precaution such as not using aluminum film and lead based paints in microwave have to be followed.
Thanks Kate for giving us the “kate flour”
Thanks for replying Kate. I’ve seen cornflour being added to allpurpose as a substitute for cake flour all the time, but I guess i was just thinking that if I was taking away the all purpose flour to match protein then I didn’t need to add anything in. It’s just that I made chocolate chip cookies one time that said to add cornflour and they were horribly dry (it’s freaked me out ever since). Since Rose and you use the cornflour substitution, I will give it a try next time!
Hi Kate,
I read with interest your formulations for kate flour. I was wondering whether microwaving the flour together with a glass of water in the microwave could maintain hydration of the flour while simultaneously subjecting the flour to the microwave processes, thereby eliminating the oven step. What do you think?
Hi Laurel – If you have a large enough microwave, I think it possibly could work (I recall reading about a similar process in industrial heat-treatment of flour, but my microwave is way too small to fit in anything other than the flour itself!). Since the flour needs to cool before I can use it anyway, I don’t find the oven step too much of a problem (I let the flour rehydrate while it’s cooling), but if you wanted to try to maintain hydration whilst microwaving, it would be interesting to hear about your results
As mentioned in my earlier comments, for “kate flour” to work moisture content of flour has to be reduced to ~2%. Flour will be naturally be rehydrated during cooling under room conditions. Typically moisture content is equilibrated to about ~10-11% (depending on the nature of the starch). I came across a research work from Kansas State University, who have described heating under increased moisture conditions to improve cake volume but is deleterious to cake texture. So I would not recommend using water glass in microwave along with flour.
However, increasing the moisture content of flour does reduce color formation. Color formation in flour is my two different mechanisms firstly, due to protein and starch at low moisture and peeling of starch (formation of dicarbonyl compounds). These two reactions are not favored at high moisture (which usually favors protein hydration and gelatinization).
In conclusion, using water in microwave is not theoritically favored
But I’m curious to know your results. Hope this helps.
Hi Kate
I made sponge cakes using Kate Flour last night and although it took wayyy too long to make Kate flour (i cheated and microwaved the flour for a minute before stirring them and yeah, they turned brown, but not too bad), it actually works! My sponge cakes are lighter! Thank you!!!
You’re a genius!
Steph
Hi Kate
Thanks so much for your comment on my blog. My xanthan gum arrived last week and my instant-read themometer today, so I am very excited to get home and get microwaving!
I no longer groan in frustration when I see “cake flour” in a recipe, and am so excited to try all the cakes that I skipped over until now.
Will let you know how it goes!
Best,
Romy