In my sourdough bread guide, I talk about starting out with a whole wheat or rye flour starter and then switching to unbleached all purpose flour. However, I've been getting a lot of questions about flour, so I wanted to do a more in depth comparison of the different types of flours so that you can choose what's best for you!
Growing up, I thought that all purpose flour was basically the only type of flour that existed. But as I've become a more experienced baker, I've come to have about 17 different types of flour in my pantry at all times (that's not an exaggeration). But don't worry, for the average home baker you can get away with all purpose for most things.
Properties of Flour
Before we can talk about which flour is best to use in sourdough, you need to understand all the different properties of flour.
By definition, flour is formed by grinding grain into a fine powder. Typically when you hear the word "flour" it's referring to wheat flour. But flour can also be made from rice, nuts, or other grains like barley. But all these different types of flour have wildly different properties.
Let's Talk Gluten
We can't talk about flour without talking about gluten! Gluten is formed from two proteins (gliadin and glutenin) found in wheat and other similar grains (like barley and rye). It's what forms the long, elastic fibers that provide structure to the bread and allows the dough to rise and expand in the oven.
In tender baked goods like cakes, cookies, or biscuits, we want to control the formation of gluten so there is very little mixing or kneading involved. Whereas in chewy baked goods like a loaf of sourdough bread or soft pretzels, we need to develop the gluten by kneading the dough.
There are lots of gluten-free flours that can be easily subbed into tender baked goods like cakes and cookies; like almond flour, oat flour, or cassava flour.
However, gluten-free bread is a little more difficult given that gluten is so important for texture. Gluten-free bread is usually more dense and lacks the open, light texture of wheat bread. It often has a more crumbly texture, similar to quick breads like muffins. To enhance the structure of gluten-free bread, additives like xanthan gum or psyllium husk are typically added.
Don't get me wrong, this isn't to say you can't make delicious gluten-free bread!! It's just difficult to replicate the open, airy texture of homemade sourdough with gluten-free flour. Gluten-free baking is not my specialty, but some of my favorite gluten-free bakers to follow are Gutsy Baker and Butternut Bakery!
Protein Content of Different Flour
Different types of flour have varying amounts of protein which is closely correlated to the amount of gluten, however it does depend on what type of flour it is. For instance, rye flour has a high protein content, but it contains different proteins than wheat and therefore has a pretty low gluten content.
Protein content in flour typically ranges from 5% to 15%. Low protein flours are typically better suited for crumbly baked goods like biscuits or pie crust. Whereas, high protein flours are better for chewier baked goods like breads, bagels, etc. Since high protein flours typically have higher gluten content, they produce doughs that are easier to knead and shape and typically rise much higher.
This is why it's so important to know the protein level of different types of flour depending on what you're trying to make!
|Type of Wheat Flour||Protein Content|
|Italian Style (00)||8-10%|
Unfortunately, many flour brands don't list the protein content on their packaging, so it can take some digging to find out the exact amount. I love King Arthur Flour for many reasons, but a big one is that they list the protein content on the front of all their packages!
As I stated above, the protein content is a good indicator of the amount of gluten-potential flour contains, however there are some exceptions. Whole wheat flour can have up to 15% protein content, but it contains the wheat bran which is sharp and can actually cut through and tear the gluten strands. So even though whole wheat flour has a high protein content, 100% whole wheat bread is usually very dense.
Types of Flour
When we're talking about flour for making bread, we're either talking about wheat flour (the most common) or flour derived from ancient grains like spelt, rye, or einkorn!
Typically when we say "flour" we're talking about wheat flour!
Wheat flour is broken down into two main categories, whole wheat flour and white flour. Wheat berries are milled to produce whole wheat flour, and then wheat flour is sifted to produce white flour.
Whole wheat flour is made of 3 main parts:
- Bran - the outer part of the wheat berry that is rich and fiber and gives flavor to bread.
- Endosperm - the inner most part of the wheat berry that is mostly carbohydrates and very important for gluten development.
- Germ - a small part of the wheat berry that is rich in vitamins and fats.
White flour is sifted to remove the majority of the bran and germ, leaving behind mostly just the endosperm of the flour.
Since whole what flour contains the entire grain, you'll get bread with a much more complex flavor but also a much more dense texture. This is because the bran actually inhibits the gluten formation, so whole wheat bread can't rise as much as bread made with white flour.
White flour will give you a more mild flavor, but a much softer texture with a large open crumb (aka larger holes inside).
Bleached vs Unbleached Flour
White flour is also divided into two main categories: bleached and unbleached. Technically, all flour is "bleached" because bleached really just means aged. As flour ages it naturally because lighter in color and softer.
Naturally aged flour is labeled as "unbleached" flour and has and ivory color. Since naturally aged flour takes longer to produce, unbleached flour is typically more expensive.
Whereas flour that's labeled as "bleached" is treated with chemicals (chlorine gas or benzoyl peroxide) in order to speed up the aging process. Bleached flour is typically bright white in color. Chemically bleaching flour also creates flour with a finer texture and slightly lower protein content. This is why cake flour is often bleached and gives a super fine, tender crumb.
The biggest thing to note when making sourdough bread, is that bleaching flour kills off any natural yeasts and bacteria present in the flour, which are essential to sourdough!! So you only want to use unbleached flour in sourdough baking! Another reason I love King Arthur Flour, is that all of their flours are unbleached.
Hard Wheat vs Soft Wheat
Wheat flour is also categorized as hard wheat or soft wheat.
Hard wheat has a higher protein content (10-15%) so that's what's used to make all purpose flour, bread flour, and whole wheat flour.
Soft wheat has a much lower protein content (5-9%) so that's what's used to make cake flour and pastry flour.
You can actually feel the difference between hard and soft wheat with your fingers! Hard wheat flour typically has a more granular feel whereas soft wheat flour has a softer, more powdery texture.
Flour from Ancient Grains
Heirloom wheats are traditional forms of wheat that have been making a big comeback in recent years. Because of that, they're a little easier to find than they used to be but still can be difficult to find depending on where you live.
Spelt flour is the more common of the heirloom varieties, and known to be less harsh on the digestive system. Spelt flour has a nutty, slightly sweet flavor and a very high protein content (17%).
However, spelt flour is not as strong as wheat flour so a 100% spelt loaf will be very dense and flat when compared to a wheat loaf.
I recommend using a small amount of spelt in addition to wheat flour to add extra flavor to your sourdough!
Einkorn flour is the earliest known cultivated wheat, and is the simplest and easiest to digest! It has a very unique flavor and also has a very high protein content (18%).
Similar to spelt, einkorn flour just isn't as strong as wheat flour so it also tends to yield a crumbly, dense loaf when used by itself.
I recommend substituting about ¼ of your wheat flour with einkorn for a delightfully flavorful sourdough loaf!
Rye flour is extremely popular to bake with because it has a complex, slightly fruity flavor and also contains a TON of wild yeasts and bacteria! For this reason, it's very popular to create rye based sourdough starters.
The protein content is similar to whole wheat (15%), however it's also very weak and nearly impossible to knead into a loaf is using only rye flour.
So again, it's best to use rye flour in combination with wheat flour for the best texture!
The Best Flour for Sourdough Bread
This whole post is essentially the [very] long way of saying there is no "best" flour for sourdough bread. It all just depends on the taste and texture you're going for!
If you're a sourdough beginner, I recommend using either bread flour or all purpose flour!
My recipe for homemade sourdough bread uses mostly all purpose flour with a little bit of whole wheat flour added for flavor. However, you can easily substitute all the flour for bread flour if that's what you prefer!
You can also make a nearly infinite number of different flour blends! So I recommend learning how to make a classic sourdough loaf with all purpose or bread flour. Then adding in different types of flour in small quantities and just experimenting with it!
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