Is there a big difference between the two? If I have a recipe that calls for unbleached flour, can I use an equal amount of regular flour? This pertains to both all-purpose and bread flours.
Some flour producers mill closer to the bran (or outer layer of the wheat kernel) so they can get more flour out of a bushel of wheat. The millers then bleach (typical bleaching agents include peroxides, Calcium peroxide, Nitrogen dioxide and Chlorine) the flour to eliminate the darker flecks of bran, giving the flour a pure white appearance. The bran left in white flour affects baking performance because its hard, sharp edges cut through gluten strands, making it more difficult to develop good structure in your baked goods.
Bleached flours (or chlorinated flours) absorb more moisture, so you may find your doughs a little stiffer when using bleached flours. Just something to keep in mind if you are seeking substitute one for the other.
I hope this information is helpful!
I used bleached flour for all my breads for years and never had any problems. I've only recently switched to unbleached because I can get the cheaper store brand unbleached.
Bleached flour *really* sucks; if you taste it in recipes where there's not a lot of other ingredients (say, simple breads without added fat or dairy, butter cookies without much vanilla (like shortbread), you'll taste the added funk that chemical bleaching adds. Additionally, the baked goods look paler and more cottony.
But yes, you can always use bleached flour of comparable protein content where the recipe calls for unbleached - the wheat police won't come arrest you. That said, there are a couple of catches: most national-brand bleached flours have lower protein contents than their unbleached brandmates, and their protein and starch are also somewhat damaged by the bleaching process, so they behave like they're even lower protein. You may have to dork with your recipes a little - a little more flour, a little less added liquid, a little different kneading time, an adjustment in baking time.
For anyone coming along after and reading this, and wondering about going the other direction, similar caveats apply, with one other: bleached flours hold liquid fat in emulsion better than unbleached flours, so there's a *small* risk, especially in recipes like muffins and quick breads made with oil or melted butter that the oil will "fall out" of emulsion and collect at the bottom of the finished product. Rose Levy Beranbaum noted this in the testing of a few of her quick breads in The Bread Bible. How I get around that is to beat the eggs and oil/butter together, like making mayonnaise, and modifying the recipe instructions accordingly.
@vibeguy: So you use unbleached flour even in cake recipes and adjust the recipe accordingly?
Yes, I've wholeheartedly switched to:
It is fantastic and is essentially indistinguishable in baking performance from KAF's saucy little bleach blonde Guinevere, which is what I used before. I think it bakes better than Softasilk.
For a long time, the substitution for cake flour has been AP flour plus cornstarch, which adds starch without gluten. That's effectively what KAF has done with this product. They've also milled it finer, I *think*; it feels more silken than AP. Someone from KAF can correct me if I'm dead wrong.
It's still got a *lot* of protein at 9.4% - Softasilk is 6.6%, Guinevere is 7.0 and KAF AP is 11.7, but somehow it all works. It may be made from softer wheat for all I know. Or it may have dark wizardry. But it works, and it makes a fantastic angel food cake.
Thanks for the info. Will have to try this once my cake flour runs out.
Thanks for the comments. Looks like it's time to do a little experimenting.