Sourdough bread mystery: what does corn flour do to the bread?

[brianhh]

I started baking sourdough bread 2 months ago after taking a class. The recipe calls for 185 g water, 2 g yeast, 158 g starter, 240g unbleached wheat flour, 40g corn flour, 7g salt, 54g soaked whole oats. It's worked out pretty well, though the loaves never got that high, usually somewhere between 2-3 inches. Sometimes wide and flat, sometimes too dense in parts.

Yesterday I baked a loaf that came out nice and light and airy and rose higher than any loaf I'd baked before, over 3 inches, and I know most of the rising occurred in the oven because I had corn flour on the pan which clung to the bread where it lifted off the pan

So what made the difference?

Here's what I did differently, but I don't know which factor could have made the difference.

1. Usually I mix water, then yeast, then starter, then flours, then let autolyse. Yesterday I mixed flour and water and yeast first, thoroughly, then added the starter.

2. I totally forgot to add the corn flour! So the dough was a bit wetter, and I had to use more flour on my hands and the board while kneading.

I think I let it autolyse for 30-40 minutes, and then let proof for about 4-5 hours.

The flavor is pretty good, though it did lose something without the corn flour. But I am just curious about what made it rise so well. And what does the corn flour do?

 

[Norcalbaker59]

The wheat kernel is comprised of the endosperm, germ, and bran.

The endosperm is primarily protein and starch. The germ is protein and fat. The bran had very low protein and is insoluble fiber.

Different types of flour contain different percentages of the endosperm, germ and bran. This is referred to as the extraction rate. The higher the extraction rate the higher the percentage of germ and bran left in the flour.

All purpose flour is about 70% extraction. So it contains the endosperm, and less germ and bran.

Cake flour is about 45% extraction. It contains all endosperm and little if any germ or bran. Cake flour is very finely milled and also bleached to change the protein structure. All of these processes produce a flour that will rise very high

Whole wheat flour is 100% extraction, so it contains all of the endosperm, germ, and bran. It is also more coarsely milled than all purpose, pastry, and cake flours.

Leaving in all of the germ and bran creates a flour with a low rise because the germ and bran absorb a lot of water. All that water adds considerable weight.

Also since the germ and bran contain no starch, leaving all of it in the flour changes the protein to starch ratio in whole wheat flour. The higher protein ratio inhibits rise.

Whole wheat flour bread is often dry an crumbly because recipes, like the one you use, has too low hydration. The whole wheat flour to water ratio is only 77% in this recipe. I don’t know what the total hydration is since I don’t know the duration levels are in your starter starter and oats. But as I mentioned earlier whole wheat flour requires very high hydration. Whole wheat flour bread requires a minimum of 90% hydration. The best bread bakers use over 100% hydration. There’s a baker in my area that uses 120% hydration in his whole wheat flour bread. Working with extremely high hydration doughs requires a lot of practice. Many bakers are unaware of the hydration requirements for a whole wheat and/or lack the skill to handle high hydration dough. So recipe developers create recipes with lower hydration levels.


The lower hydration produces a whole wheat bread that is dry, crumbly, and tough. To counter some of those effects, they add corn flour. The theory being the added starch will produce a softer loaf with high-rise. The problem is the thickening from corn flour can inhibit rise.


When a higher rise and softer loaf is desired, it’s best to mix whole wheat and all purpose flour. If you want an all whole wheat flour loaf you just have to accept a low rise as part of the characteristics of a whole wheat flour loaf. But you will get a better rise and softer loaf by using the appropriate amount of water.


Good recipes for whole wheat and all purpose blends are on the Perfect Loaf blog. He also has recipe for an all whole wheat flour loaf.




https://www.theperfectloaf.com/fifty-fifty-whole-wheat-sourdough-bread/


https://www.theperfectloaf.com/100-whole-wheat-sourdough/

 

[brianhh]

Great info, thanks. But I guess I wasn't clear: I wasn't using whole wheat flour. It's unbleached bread flour.

 

[Norcalbaker59]

Great info, thanks. But I guess I wasn't clear: I wasn't using whole wheat flour. It's unbleached bread flour.

No you were clear, it was my misreading. Bread flour is high extraction flour of 85% - 88% (or higher depending on the mill). It rises better and produces a softer loaf than whole wheat. Why anyone would add corn flour to bread flour is beyond me since bread flour has great characteristics for bread.

The amount of hydration may seem like a lot when you omitted the corn flour. But high hydration is a very good thing for bread.

Rather than knead the bread dough develop the gluten using high hydration techniques. Adding a lot of extra flour In kneading causes a lot of problems.

 

[brianhh]

Thanks, this is all useful information. I have played around with whole wheat flour as well, so will use your suggestions for whole wheat bread. The original recipe I had did not use bread flour, but an unbleached wheat flour from tall-stalk wheat. I ran out of that and started using bread flour. That video was very interesting as well.