I was just putting away my cornstarch when I saw this on the label: To make cake flour: For 1 cup cake flour combine 3/4 cup plus 2 Tbsp. all-purpose flour with 2 Tbsp. Argo Corn Starch.

Of course I see this two days after paying a ridiculous amount of money for Softasilk.

I usually use AP flour for simple cakes, but I'm making some really fussy desserts for the holidays. Some of those recipes call for cake flour and I've always gone ahead and bought cake flour for that kind of thing. Would I really get as good a result with that substitution?

  • I will say that it is a good substitution, because technically, there is no difference - it is like asking if mixing salt and garlic powder is a good substitute for garlic salt. But as I have never actually baked with the "real" products, always with the substitutions (meaning it in both directions here - ap + starch as well as ap + gluten), I will not make this an answer, because sometimes the real world doesn't behave according to theory :)
    – rumtscho
    Nov 20, 2013 at 15:17
  • @rumtscho There is no cornstarch or anything else but flour and "enrichments" listed in the ingredients of my cake flour (Softasilk).
    – Jolenealaska
    Nov 20, 2013 at 15:24
  • I think it would be useful to split this question into two.
    – Mien
    Nov 20, 2013 at 15:25
  • 1
    Cake flour is milled from soft summer wheat, finely ground, and bleached. It is not a blend of products.
    – SAJ14SAJ
    Nov 20, 2013 at 15:26
  • 1
    @Jolenealaska yes indeed, although the other question is broader while yours is to the point. I'm not 100% sure it is a dupe, but that is why we have a community :)
    – Mien
    Nov 21, 2013 at 16:24

1 Answer 1


It all revolves around gluten and gluten chains.

Cake flour is low protein, and bread flour is high protein, and everything else lies somewhere between. Individual brands have different levels of protein depending on their formulation. That protein, when combined with water, is what makes your stretchy gluten chains, and those are the difference between soft crumbly cake and a french baguette that could serve as a weapon in a pinch.

As with many chemical reactions in cooking, however, you can interfere with the "natural" reactions by means of some clever chemistry. Cornstarch works very simply...Corn just doesn't have any gluten, so you're just "watering down" the gluten content of your flour.

Acid retards gluten formation. Water is critical for gluten formation, unless you use a whole lot of it, in which case it weakens it (a wetter dough will make for a less gluteny final product). Mixing makes more gluten (helps the little proteins make friends with each other), so mix MORE for more gluten, and less for less.

But fat is your friend. Fat waterproofs your flour, and keeps gluten from forming.

Long story short, pick a method you're comfortable with, and stick to it. If you're used to using AP flour, you're going to have some headscratching moments when the cake flour doesn't behave the way you expect it to. On the other hand, cake flour will be more forgiving if you overmix.

  • So fat is not your friend when you're making bread? Do you need to knead an enriched dough more than a standard one? Or is the amount of fat small enough to not prevent gluten formation? Even in brioche?
    – Mien
    Nov 21, 2013 at 14:42
  • @Mien: You'll notice a difference in proportions, in the recipes. Cake tends to have a much higher proportion of fat to flour than bread does. And all that kneading is for gluten formation: bread is mixed far more than cakes or quickbreads. If your bread tends to be crumbly and lacking in structural integrity, might want to look into a higher protein flour...On the other hand, if you can't chew it, might want to go the other way ;) Nov 21, 2013 at 14:54
  • I generally use whatever flour (cake, AP or bread) the recipe calls for. I might use AP instead of one of the others if it's just a simple throw together thing. I make a fussy angel food cake that's kind of a special to me. Even the granulated sugar gets almost powdered in the food processor. Could AP plus cornstarch really replace cake flour in something like that, or is more of an emergency substitution kind of thing?
    – Jolenealaska
    Nov 21, 2013 at 15:41
  • @Jolenealaska: Angel Food has so much protein in it (egg whites are pure protein), I'd think the type of flour would be redundant ;)...The King Arthur AP flour version (kingarthurflour.com/recipes/traditional-angel-food-cake-recipe) is virtually identical to the traditional cake flour version (and KA flour is very high in protein). I don't think I'd add cornstarch for AP Angel Food: all those eggs, and the cream of tartar should cover the difference in protein between normal AP and cake flour. Nov 21, 2013 at 16:05
  • @Satanicpuppy You certainly have a point, although I'm not totally convinced. A brioche can have about butter to flour in a 1:2 proportion, while I have baked cakes which had almost no fat.
    – Mien
    Nov 21, 2013 at 16:27

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