For the baker, there is a wide variety of flours to choose from when making a cake. Some of the options include: bleached cake flour, unbleached cake flour, pastry flour, self-rising flour, unbleached all-purpose flour and bleached all-purpose flour, not to mention starch substitutes and hybrid variations of some of those above. It can be a bit confusing which is the best flour for cake baking. Here I hope to demystify some of the what’s and why’s of cake worthy flours.
To illustrate the affects of varying flours, I baked six cakes each with a different flour type or combination. These included: unbleached all-purpose flour (UB) , bleached all-purpose flour (Bl.), bleached cake flour, potato starch plus unbleached all-purpose flour (a common cake flour substitute), half cake flour/half unbleached all-purpose flour and half cake flour/half bleached all-purpose flour.
Before we get onto the results of the baking, let’s talk about the differences in the flours.For this, I created a really awful graphic, but I thought a goofy little figure might help those of us that are über visual. This is an illustration of a baked cake using either cake flour or all-purpose flour.
There are two major differences between flours.
- Protein content: Cake flour is a low protein flour which means it contains more starch and less protein ounce for ounce than an all-purpose (plain) flour or a bread flour. In the figure above you can see how this comes into play in a cake. The structure of the cake made with cake flour is mediated primarily by swollen starch granules with some structural help from egg proteins and the minimal protein found in cake flour. All-purpose flour contains more protein and less starch by weight than cake flour and therefore the resulting cake structure is held together with more of a flour protein network.
- Chlorination: Bleached flours have been treated with either chlorine dioxide or chlorine gas. This process not only lightens their color but also causes their starch granules to swell more easily and disperse fat more readily. Chlorination or bleaching also produces a distinct flavor that some people care for while others do not. The fact that chlorination leads to the accumulation of specific molecules in the body has caused it to be outlawed in the European Union and United Kingdom. Cake flour is usually bleached but King Arthur offers an unbleached variation.
In actual cake, these are how the differences translate:
- Unbleached all-purpose flour and bleached all-purpose flour appeared similar in color with a moist but slightly coarse crumb.
- The bleached all-purpose flour rose just slightly higher than the unbleached.
- Both the bleached and unbleached all-purpose flour cakes held together well.
- The cake made with cake flour was taller and lighter in color than the all-purpose flours but was also drier and more crumbly/sandy .
- The cake made with cake flour was more compact and less spongy seeming than the all-purpose flour cakes.
- The cake flour cake had a slightly finer crumb than the all-purpose flours.
- The cake made with cake flour tasted somewhat of chlorination.
- The unbleached all-purpose flour with potato starch was the shortest and darkest of the cakes but it had a moist, tender crumb.
- The half cake flour/half all-purpose flour combinations were almost identical to one another, but the bleached flour/cake flour combination rose slightly higher than the unbleached flour combination.
- Both of the half cake flour combinations held together well and had a moist, tender, fine crumb.
So what is the best flour to use for your cake? That depends a lot on what you are looking for and what flour types are available to you. I prefer a combination of cake flour and unbleached all-purpose flour. I don’t care for the taste of cake flour so I try to limit the volume that I include. I also like the moisture and structure that all-purpose flour provides. This combination is essentially like pastry flour. If you have access to pastry flour I think it is a great option for cake.
On the other hand there are times when someone may want the whitest, tallest cake possible and therefore cake flour may be the best option.
The flour choice is really up to you and your preferences. I hope this information will help you to make an informed decision!