What's the difference between bleached and unbleached all-purpose flour?

Recently someone told me that cakes made with bleached a.p. flour are more tender than those made with unbleached a.p. flour. Is this true? If so, can someone explain what happens in the bleaching process to weaken the gluten?

Amanda Hesser


hardlikearmour February 17, 2011
betteirene, it's gotta be a good thing you don't eat pork rinds every day!
betteirene February 17, 2011
TeeHee--that last sentence makes it sound as if I eat pork rinds every day for breakfast. I don't. But I do use CoffeeMate every day.
betteirene February 17, 2011
I use unbleached AP, even when Dorie Greenspan tells me to use cake flour. I do the two-tablespoons-less per cup substitution, and I find a negligible difference in tenderness/texture/crumb.

I can be so anal about some things and mellow about others. Unbleached flour is one of my kitchen eccentricities. Here's why: Make a pie crust or vanilla slice-and-bake refrigerator cookies with bleached AP flour, and make another batch with unbleached flour. Wrap them both in plastic and put them in the fridge. On the second or third day, look at the dough. One of the packages, the one made with unbleached flour, will be an unappetizing grey; I guarantee you'll think twice about baking this dough, even though there's nothing wrong with it except the color. The other package will be the same white-yellow-beige color as the day it was made, because that's what Clorox is supposed to do--it keeps your whites whiter.

Bear in mind that the person who'd like you to think twice about eating chlorinated flour is the same person who eats pork rinds and uses CoffeeMate every morning.
nutcakes February 17, 2011
I use unbleached for everyday use and for cookies. I'd like to remember to use bleached for cake (unless the recipe calls for cake flour), but I never have it on hand.
hardlikearmour February 17, 2011
If I'm using AP flour it's always unbleached. If I'm using cake flour it's bleached.
Blissful B. February 17, 2011
Satellite question -- how many of you use bleached vs. unbleached flour?
nutcakes February 17, 2011
I like hardlikearmor's answer, but thought that I'd mention that I went to a lecture by the Gold Medal people at a Baker's Dozen meeting. They just told us that the protein content is lower. They said KA flour has the highest, then Gold Medal unbleached.
ChefJune February 17, 2011
I don't know for sure, but I do know that over the years White Lily makes the most tender cakes and pastry. They claim it's the soft winter wheat makes for a lower gluten flour.

Stands to reason that the chlorine would make some difference, too, though.
Sasha (. February 17, 2011
What Harold McGee said... also I think flour naturally bleaches on its own over time, my understanding is that it was originally done to hurry things along from the sales point of view as well as (perhaps more significantly) for uniform results. Not sure where I got this idea though - maybe in one of the King Arthur Flour baking classes I took..? Who knows :)
aargersi February 17, 2011
Hey lady do you have my house bugged? Because we were literally sitting here (in Ginger's kitchen :-) talking about that VERY topic, so we looked at all of my flours then looked it up!

hardlikearmour February 17, 2011
From Harold McGee (On Food and Cooking): "the chlorine treatment turns out to cause the starch granules to absorb water and swell more readily in high-sugar batters, and produce a stronger starch gel. It also causes fats to bind more readily to the starch granule surface, which may help disperse the fat phase more evenly" From Rose Levy Beranbaum (The Cake Bible): "Cake flour, due to bleaching by chlorination, has a lower pH than other flours. This produces a sweeter flavor and a finer, more velvety crumb because the greater acidity lowers the temperature at which proteins coagulate. This also makes it possible for the cake structure to support more sugar, butter, and heavier particles such as chopped nuts or chocolate. The chlorination process offers other advantages....Chlorination also serves to inhibit gluten formation. Recent research has revealed that fat adheres to the surface of chlorinated starch particles, resulting in better aeration."
I assume it inhibits gluten formation because the fat adheres better and interferes with making gluten.
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