Which Flour to Use for Sourdough Bread: A Complete Guide


When I first started learning to bake sourdough bread, I had no idea that using a different flour for the same recipe could give me such a different bread result. All I knew back then was ‘white flour’ and ‘whole wheat flour’. Now, I love mixing up different types of flours knowing the potential results and flavors it will bring. And I love even more, experimenting with different flours to see what happens to my bake.

What type of flour is best to use for sourdough bread? If you’re a complete beginner, organic strong white bread flour made from hard wheat is the best option. This flour will:

  • give you the easiest and strongest gluten development
  • will be easiest to knead and shape
  • will give the best rise in the oven

But learning about different flours and their properties is very useful. This knowledge will help the sourdough baker really stretch their baking skills and produce a variety of different types of bread. Here’s my complete guide to different flours, their properties, their pros and cons, and how/why to use each of them in a sourdough bake.

Organic Flour vs Non-Organic Flour for Sourdough Bread

When it comes to sourdough bread, we are counting on natural organic wild caught yeasts. Therefore, it is logical to use choose organic flour whenever possible to bake sourdough bread, as it is natural and chemical free.

Non-organic flours are often bleached, which means they are chemically treated to whiten and age the flour. Organic flour tends to have a higher mineral content and so sourdough starter is better able to utilise the minerals from the flour without the interference of added chemicals.

What Happens if I use non-organic flour to bake sourdough bread?

I have used both organic AND non-organic flours to bake sourdough bread before, and here’s what I found:

Using non-organic flour:

  • gives a less flavorful loaf
  • still gave a good rise and structure to the bread
  • made my sourdough starter smell much more acidic and ‘chemically’ (rather like nail varnish)
  • sourdough starter seemed less active

Using an organic flour:

  • My sourdough starter smelled more like ‘baked bread’ or ‘fruity beer’
  • gave a much more complex flavor profile
  • sourdough starter became very active and gave good rise

Both organic AND non-organic flours produced results for my bread, but going with organic tended to give me much better flavor.

The theory is, that using organic flour contains a slightly different profile of mineral content, and doesn’t contain the added chemicals in it. So, when it is fermented, it gives a more natural and diverse range of flavors than standard non-organic wheat flour. [Ref]

The truth is, a strong, mature sourdough starter will still bake good bread even if using a non-organic flour. So if you’re in a pinch, or on a budget, don’t worry too much. As long as you try your best to feed your sourdough starter with a good quality organic flour, your starter should be strong enough to still bake excellent bread whichever flour you use for the rest of the bake.

Organic flour resultsNon organic results
Better flavor profileBlander flavor
More active starterLess active starter

Whole Wheat Flour vs White Flour

Wheat berries are milled to produce whole wheat flour, and sifted to produce white flour

Using whole wheat flour compared to white flour, in whichever variety of wheat you use, will have a huge impact to the flavor and texture of the bread. Whole wheat flour contains the entire grain of wheat. This includes:

  • The bran – Found on the outer part of the wheat berry
    • rich in fiber and minerals
    • This is the part that give most flavor to sourdough
  • The endosperm – The inner most part of the wheat berry
    • rich in starch, and made up mostly of carbohydrates and proteins
    • This is the part that is important for gluten development in bread
  • The germ – A small part of the wheat berry
    • rich in vitamins and healthy fats

White flour on the other hand contains a lot less of the bran and germ. It has mostly the endosperm left, depending on how finely it has been milled.

Using whole wheat flour in sourdough bread will give you:

  • A much more complex flavor profile, due to the range of minerals found in the bran.
  • A more dense and heavy texture of bread.

Using white flour will give you:

  • A lighter, softer textured bread with a more open crumb (larger holes and a more aerated structure)
  • A milder, more simple flavor profile

The more wholemeal you have in your sourdough, the more dense it will be, but the more flavor it will also have. This knowledge enables you to manipulate the bread by using different ratios of whole wheat to white flour, and produce a loaf that is exactly how you like it in terms of flavor and crumb.

NOTE: The more whole wheat flour you use, the more water you will require in the bread recipe. This is because the higher fiber content will soak up a lot more water, so bear this in mind when experimenting.

Whole wheat floursWhite flours
Denser textureOpen crumb
Less riseMore rise
Complex flavorMild flavor

If you’d like more detailed information about how whole wheat bread compares to sourdough, have a read of my article, “Sourdough Bread vs Whole Wheat: A Guide to Which is Better”.

Stone Ground Flour vs Regular Flour for Making Sourdough Bread

Stone ground flour has made a bit of a comeback in recent years and shows no sign of slowing down. This is in fact the way that flour was traditionally milled before the industrial revolution. It consists of two large stones grinding the wheat berries down until it turns into flour. This produces a whole wheat flour that is courser in texture. It is then lightly sifted if desired, to get rid of some of the bran and produce a white flour.

Nowadays of course, the vast majority of flour is roller milled. It’s a faster technique that gives more consistant finer textures to the flour. The wheat berries pass through the middle of 2 large steel rollers and get crushed as they go through, removing and seperating the outer bran section as it passes through. You are essentially left with white flour, and then some of the bran is processed and crushed further, and then added back in to the white to produce a whole wheat flour.

Using Stone Ground Flour for Sourdough Bread

Traditionally, wheat was ground between two large stones to make flour

Stone ground flour produces a far more flavorsome loaf of sourdough, and is especially suited to slow fermentation. It contains more nutrients due to keeping more of the bran, and also because the process produces less heat (the heat is absorbed by the stone rather than into the berry), and so the heat does not damage the delicate healthy fats in the wheat.

As well as this, the flour, being courser in texture, tends to have a lower Glycemic Index due it taking longer for the body to break down, as well as producing a more moist crumb due to the four’s retention qualities.

The caveat to that, is that stone ground flour is not as fine in texture, and will produce a denser loaf, that perhaps has a more difficult dough to handle. But many bakers insist that the flavor (and nutrition) that come from using stoneground flour is something along the lines of ‘out of this world’.

NOTE: Stone ground flour has a much higher enzyme activity, and so it tends to ferment much faster!

Using Roller Milled Flour to Make Sourdough Bread

Roller milled flour is far more consistent in its flavor, grind, and performance, so it will give you a more consistent and solid result when it comes to sourdough bread. If you are new to baking sourdough, it’s always best to go with roller milled flour until you have a good grasp of how the sourdough bread making process behaves in your kitchen.

The caveat to that of course, is that the flavor is not as complex, and it’s not as nutritious. Roller milling is very harsh to the wheat berry both physically and how much heat is produced, and so nutrients are lost in the process far more, than in stone ground flours.

Stone Ground Flours Roller Milled Flours
More complex flavorsLess flavor
Courser grainFine grain
Dough harder to handleEasier to handle
Denser breadLighter more open crunb
Less consistencyConsistent results
More nutritiousLess nutrients
Lower GIHigher GI

Fine Ground vs Coursely Ground Flour

Regardless of the milling method used, the finer the flour is milled, the more it will rise. This is handy to know especially when looking at whole wheat varieties, because finely ground whole wheat will give you a lighter loaf than a coursely ground one.

Freshly Milled Flour

Freshly milled flour, whether roller milled or stone ground is a whole different league when it comes to flavor, nutrition and workability. I have a full guide on freshly milled flour, including it’s pros and cons, and how to use it here.

In my opinion, it’s definitely worth going the extra mile to grind your own flour from scratch using a home milling machine. Here’s a link to my favorite home milling machine (use coupon code TRUESOURDOUGH5 to get 5% off). It’s a solid quality stone ground flour miller that’s simple and quick to use.

(If you’re on the look out for a home milling machine, check out my Baking Tools section with a buying guide on how to choose the right home milling machine for your needs). Freshly milled flour can either be used straight from the mill, or after it has been ‘aged. Both scenarios will produce different flavor profiles!

Protein Content in Flour

Flour has to contain enough protein and strength to get good gluten development

The percentage of protein in each type of flour differs, and it is important for a bread baker to understand which protein level is right for them. There are many different proteins found in wheat, which when hydrated, kneaded and/or fermented, produce gluten. Gluten of course is what gives bread its ability to increase in volume, maintain structure, and develop into bread. As fermentation produces gas, gluten strands help to hold up the dough and trap the air inside the bread.

The more protein you have in your flour, the more gluten can be developed in your dough. Protein content can range from 7% to 15%. The lowest protein flours being more suited for crumblier textured goods such as cookies and pastry (sometimes known as soft wheat), and the highest protein flours are more suited to chewier foods, such as breads (aka hard wheat). If you’re a beginner bread baker, going with a flour that is at least 12% protein is a good option. Higher protein flours make doughs that are easier to knead and shape, and will produce higher rising loaves of bread with good structure.

High Protein Flours Low Protein Flours
Chewier textureCrumblier texture
Higher riseLower rise
Easier to knead/shapeDough not stretchy

Strength of Flour vs Protein Content

The protein content can give you an idea of how much gluten can be developed, but the QUALITY of the gluten can better be determined by the strength of the flour. The strength of flour is actually measured by something called the ‘W Index‘, but when it comes to buying flour, the best way to judge if a flour is high in the W Index, is to look for the words ‘strong‘, or something of that nature on the label. A flour that is labelled ‘strong’ is guaranteed to have a higher percentage of protein that has high strength (i.e.highly extensible and stretchy). The label may say:

  • strong
  • very strong
  • bread flour

Ash Content and Extraction Rate

You may hear bakers talking about the ash content in flour when baking bread. This is simply the level of minerals that remain in the flour once it has been milled. In other words, the higher the ash content, the more bran and germ there is in your flour (as this is where all the minerals are).

Ash content will have an affect on the density and flavor of your bread. The higher the ash content, the denser the texture, but the more complex the flavor. For your reference, here’s a list of average ash content levels for different kinds of flours, including bread flour:

Type of FlourApproximate ash content level
Pastry flour0.45%
All Purpose flour0.55%
Standard bread flour0.65%
Artisan Bread Flour0.8%
Light whole wheat flour1.1%
Dark Whole Wheat flour1.4%

When it comes to sourdough bread, you should ideally go for an ash content of between 0.8% and 1.2% in order to develop a good flavor profile. The higher ash content flours contain more minerals and so more yeasts are encouraged to be produced at a higher level in the sourdough, which helps develop more flavor.

What is Extraction Rate of Flour?

Bread flour should have at least 70% extraction rate to produce good flavor for sourdough

Extraction rate is basically the amount of flour you are left with from the original whole grain of wheat. For example, wheat that is stone ground and not sifted at all will have 100% extraction rate, because 100% of the grain is still remaining in the end flour result.

A high extraction rate flour will have far less bran and germ left in it than a low extraction rate flour. For reference, here’s a quick list of extraction rate’s of flours:

Type of FlourApproximate Extraction Rate
Stone ground whole wheat flour100% extraction rate
Strong White/Bread flour72% extraction rate
Cake/pastry flour50% extraction rate

What does this mean for Sourdough Bread?

As mentioned earlier, there is a fine balance between having enough bran in the flour to develop flavor, but also having enough gluten development in it to give a good structure. Flour with extraction rates of around 70% work well for sourdough bread, as long as there is also a high enough protein content and strength in the flour.

Different Varieties of Wheat

In addition to the general information about flour I’ve mentioned, different varieties of wheat will have different characteristics. It’s useful to understand these, so that you are better able to experiment with different flours and flavors with greater success. Here’s a closer look into the some of the possible flours you can use for your sourdough bread, and what affect they may have on your bread result.

Hard Wheat

This is the most common type of wheat in the US. There are a few variations of this type of wheat:

  • Hard red winter wheat
  • Hard red spring wheat
  • Hard white wheat

All of these wheat varieties (assuming they are white, NOT whole wheat) are an excellent choice for a beginner sourdough baker for a few reasons:

  1. They all have a high protein content
  2. They are all strong wheat varieties, producing ‘bread quality’ gluten
  3. They are easy to handle when making sourdough and will not be as sticky
  4. They are very widely available

TIP: If you can find ‘strong’ or ‘bread flour’ versions of this wheat, that is even better!

Heirloom Varieties of Wheat (aka Ancient Grains)

Heirloom wheat are traditional forms of wheat that have made a big come back in recent years. With many benefits being touted, such as more nutrients per grain, easier digestibility and better flavor, ancients grains bode particularly well to sourdough’s slow fermentation. In fact, experimenting with heirloom varieties in sourdough bread baking can bring a whole mix of potential complex flavor combinations to sourdough bread! Here’s some information about each one, and what you need to know before using them.

Spelt Flour

Spelt flour is the more common of the heirloom varieties, and known to be less harsh on the digestive system. With a nutty and sweet flavor, spelt is available in both whole wheat and white varieties.

  • Protein Content – 17%
  • Strength – Low on the W Index (i.e. not considered a strong wheat)
  • Special Characteristics
    • A 100% spelt sourdough bread will be slightly more difficult to handle than modern wheat.
    • Spelt is highly extensible (due to its high protein level), but doesn’t have a lot of elasticity (as it’s not very strong). This means that although the dough can stretch out a lot, it won’t spring back too easily. The resulting loaf will have a denser texture and flatter shape, but a wonderful slightly sweet, nutty flavor.
    • Spelt is also less absorbant, so you may need to use less water in your recipe.

Einkorn Flour

Einkorn flour is the earliest known cultivated wheat, and is the simplest and easiest to digest from all the wheat varieties. It has a wonderful unique flavor and produces a beautiful golden colored bread.

  • Protein content – 18.2%
  • Strength – Low
  • Special Characteristics
    • Although higher in protein than other wheat varieties, the gluten structure is a little different; It should NOT be kneaded too much, or it will lose it’s integrity and become a big lump of runny mess!
    • Einkorn tends to give sourdough bread a more crumbly but light texture.

Khorasan Flour

This flour is also known as kamut, and originated in Egypt, dating back to use during Pharaonic times. It’s still a common wheat used in Egypt and surrounding areas. This ancient grain has a high nutrition count and excellent rich flavors.

  • Protein content – 16%
  • Strength – Low
  • Special Characteristics –
    • Like spelt, it is extensible but not elastic, resulting in a soft, but slightly dense texture.
    • It is more absorbant than modern wheat, and so the recipe will require more water.

Rye Flour

Available as both dark rye (whole wheat rye) and light rye (sifted to remove the bran), rye flour and sourdough are like best friends. There’s a reason why many artisan bakeries often add rye to their sourdough breads, and it’s because rye is like a super food for wild bacteia and yeasts, and is notorious for being the perfect addition to sourdough, adding wonderful complex fruity flavors. (For more detailed information on rye flour, have a read of my article “6 Reasons Rye is Popular in Sourdough & What to Know Before Using It”)

  • Protein content – 15%
  • Strength – Extremely Low
  • Special characteristics
    • Rye contains enzymes that make it highly active, which means it ferments at a quicker rate.
    • With such a low strength, using 100% rye will make it impossible to knead, and will only bode well to pouring into a loaf tin, giving you an extremely dense but tasty loaf.
    • Rye absorbs more water than modern wheat, so you may need to add more water than usual if adding rye to your loaf.
    • But it also retains moisture well, even after it’s baked, which perhaps compensates a little for the compromise in density levels.
SpeltSweet nutty flavor
Low gluten strength
Denser crumb with flatter shape
Absorbs less water
EinkornCrumbly light texture
Not to be kneaded too much
Low gluten strength
Golden color
KhorasanSoft, slightly dense texture
low gluten strength
Absorbs more water
Nutty, rich flavor
RyeCannot be kneaded
Ferments quickly
Dense, moist texture
Fruity complex flavor
Needs more water
Each type of flour has its own unique characteristics

Tips when Working with Different Flours in Sourdough Bread

Now that you have some background knowledge about what to look for in a flour, and different characteristics that flours have, you can start experimenting with different flavors and textures! It’s important to note that each flour will come with its own learning curve. And the more you bake with it, the more you will learn to manipulate your sourdough until you achieve that perfect balance of flavors and textures. Here are some tips to start you off on your journey to sourdough success.

Tip #1: Perfect your First Loaf

This is especially important if you are new to baking with sourdough. Start off with an easy to use flour, and get good at this first, before starting to experiment with other flours. A good starting flour is organic strong white bread flour. This flour is relatively easy to handle, and is more likely to give you a successful loaf of sourdough bread with a high rise, and open crumb. Once you feel confident making this type of loaf and understanding its behavior, you can move on to other flours.

Tip #2: Get to Know your Flour and Make Notes

When working with a new type of flour, use the guide above to understand its unique characteristics and adjust your recipe accordingly. For example, if a flour is more absorbant, be ready to add extra water in to the mix and make note of how much water you have added in. If it is a more active flour, make note of how much quicker it fermented. Making notes means you will improve with every loaf of sourdough you make, because you will be able to look back and see what affected the bread.

Tip #3: Add a Little at a Time

Using new flours, will inevitable be more difficult to use than ordinary bread flour. So one way to soften the learning curve is to add a small proportion of the new flour (maybe 10%) to begin with, and note down the difference it made to your usual loaf. Think of it like training, the more alternative flour you add, the more you will learn to handle different flours.

Tip #4: Use Loaf Tins for Support

If you end up with a dough that is particularly difficult to handle, make use of a greased loaf tin to bake your bread in instead of a banneton. A loaf tin will help hold up the structure of your bread by supporting the sides and will force the bread to rise upwards rather than outwards.

I hope you found this information useful. For more tips on baking better sourdough bread, visit the Baking Tips Section.

Aysha

I've been baking sourdough bread at home for years now and have had a journey full of successes and failures. This has given me great experience in understanding what makes a good bake!

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