Friday, July 16, 2021

revisiting the "do fats hamper bread rise?" question

Here is a long quote from a baker discussing how to make keto bread. The quote sits beneath a video she made showing the difference between using whole eggs and egg whites only:

I have been receiving questions on why we need to use egg whites and not whole eggs for making keto bread. So today, I am going to show you the differences [between] using egg whites and whole eggs.

First of all, why do we need eggs in keto bread? Eggs [work] as a binder, [and they provide] bulk, structure[,] and moisture as well. How [many] eggs we use would depend on the type of [low-carb] flour and its quantity. For example, coconut flour is very absorbent[, so] it needs more eggs while other [types of] flour may need less.

Regular wheat flour is light and rises so well due to the protein from gluten. On the other hand, [low-carb] flours are non-gluten and [contain] more fats as they are made from seeds, nuts[,] and coconut. Hence, keto bread tends to be heavier [and] denser[,] and [it does] not rise as much as regular bread[,] even with baking powder and yeast. That is why by adding more protein into the bread, it will help to boost the rise. And when the bread rises more, it will be lighter, softer[,] and fluffier.

All this while, I have been recommending to use egg whites instead of whole eggs for making keto bread because the protein from egg whites helps to boost the rise of the dough while the fats from the yolks [hinder] the rise. Additionally, using egg whites will also make the bread look lighter in color and prevent any eggy taste.

Both versions with egg whites and whole eggs will rise as the latter still [contain] some egg whites. It is just a matter of how much they rise [that] will ultimately affect the texture. So if you prefer to use whole eggs, feel free to do so. I know that there are people who love eggs[,] and they don't even mind the eggy taste. This video is just to show you the differences for better understanding so that you can choose which option to go for.

In this video, I used my latest Keto LSA Bread (v2.0) recipe which is made from [linseed or flaxseed, sunflower seed and almond]. Here's the link to watch the video -

If you choose to use egg whites, here are some ways that you could use the leftover egg yolks[:]

1. Scrambled eggs (add some whole eggs)
2. Steam eggs (add some whole eggs)
3. [Low-carb] fried rice
4. Egg tarts
5. Crème [Brûlée]
6. Egg custard
7. Ice cream
8. Pasta sauce
9. French Buttercream
10. Lemon Curd
11. [Caesar-salad] sauce
12. Hollandaise sauce
13. Mayonnaise
14. Flan
15. Indonesian layer cake
16. Lemon bars
17. Lemon tarts
18. Aioli
19. Chewy cookies
20. Salted Eggs (Cured eggs)

If you have any other suggestions, do leave a comment below.

So I bolded the important part. This lady seems to agree that fats do reduce the rise of a bread, which appears to confirm my intuition. She notes that, for normal breads, the rise has a lot to do with the gluten in regular wheat. In a comment, my buddy Charles noted that cakes have a lot of fat, but they rise just fine. I think this lady's response would be that cakes are made with wheat flour, so a cake's rise is about the gluten in the wheat. Make of that what you will.


Charles said...

"I think this lady's response would be that cakes are made with wheat flour, so a cake's rise is about the gluten in the wheat."

But that's not how cakes work. Cakes are made with baking soda/powder and aren't kneaded, so there isn't enough time to really work the gluten. This is why cakes tend to be light and fluffy as opposed to chewy--if you actually could get the gluten in a cake batter worked into a structure the same way that you do in a bread, you'd end up with a pretty crappy cake!

I don't remember where I made that initial comment, so I'm not quite sure of the context, but I think what I was probably trying to say was that the keto breads you were trying were more cakes than breads, and thus they should operate more or less on the same principles as typical cakes. I could very well be wrong about that. But the point is that if you are using baking soda and not kneading the dough (which you generally don't do when using baking soda), the rise is not a matter of gluten structure.

That being said, too much fat in a yeast bread can indeed inhibit the formation of gluten--something about the fat coating the proteins, preventing them from forming into a web structure. For yeast breads that are very high in fat (like butter in a brioche), the fat is often added after the dough has been sufficiently kneaded to form the gluten. So if you were making a yeast bread with a high fat content and you added the fat from the very beginning, you might very well have problems.

In the case of keto bread, your guess is as good as mine--probably better, since you've had hands-on experience. It's possible that the dough is simply too heavy to rise all that much, since it can't rely on a strong gluten structure, and it's possible that extra fat makes the dough heavier. If that is indeed the case, I wonder if altering the structure of the fat would help. More specifically: What if you tried making an emulsion with your fats and then added the dry ingredients to that? This is basically how I make my cakes, and it leads to a very light and fluffy crumb. I don't expect that keto bread would act in quite the same way, but if you start off with an emulsion and carefully fold the dry ingredients into that, you will have a ready-made structure that could lead to a higher rise. This would only be for the soda versions, of course.

Will it work? No idea. But it might be interesting to try.

Kevin Kim said...

The experiments will continue for sure once I'm done with the Newcastle Diet.

Kevin Kim said...

I'm not clear from your comment, though, as to whether the lady is right or full of shit. Anyway, she has an almond-bread recipe that seems to bake up like white bread, so I'm going to buy a baking pan (I keep having to purchase new ingredients and equipment) and give it a try.

Keto dough, if it has baking soda, normally isn't kneaded, but it is often stirred. How much of a difference does that make?

Kevin Kim said...

I'm trying to sort this all out in my head. At first, it seemed to me you were saying the lady was wrong, but then you got to talking about keto bread being a different animal with cake-like traits, so it is possible for fats to affect the cake's/bread's rise. Since I charitably assume you're not contradicting yourself (i.e., any confusion is entirely on my end), I'm guessing what you're saying is that, for wheat/yeast breads that are kneaded, we can talk about gluten development, gluten web structures, etc. But for soda breads, cakes, etc., we can say that fat can, in fact, impede a rise, and the whole issue has nothing to do with how gluten is developed in normal bread. If that's true, then I think my basic intuition is still correct, even if I got some details wrong. Add too much fat, lose the rise.

I didn't link to the lady's white-bread video (here), but in it, she foams up egg whites to stiff peaks and folds them into her bread batter, which I imagine helps the crumb become more airy.

Charles said...

It's possible that my comment was confusing because I am still trying to sort all of this out myself, and because I cannot claim to have any real expertise when it comes to keto "bread."

The truth is that I really don't know how a dough/batter with no wheat flour will react to having too much fat in it. I know that there are certain things you have to be careful of when making a wheat-based bread or cake, but we might very well have to throw all of that out of the window when it comes to keto bread. I also don't really have a good feel for exactly how much fat these keto recipes have in them--probably a lot more than my breads usually have, at least.

If you got anything wrong, it was the bit about cakes and gluten structure. That was all I was really trying to say there, and perhaps I took too many words to do it. As for the rest, your summary in your last comment seems to cover everything.

Whipped egg whites is what you use to get most of the rise in a chiffon cake, and such a technique would definitely lead to a lighter crumb. That would make your bread a very different animal than if you made an emulsion. When you do get back to baking, I would say give both techniques a try and see how they compare.