Have you ever asked the question "is sourdough bread gluten free?". Perhaps you've just taken up the challenge of baking your own sourdough bread and you're curious as to how much gluten there actually is in sourdough bread.
Sourdough bread is not gluten free (unless you make it with gluten free flour).
If you make sourdough bread with wheat flour, it will contain some gluten, despite the fermentation process which does help to break down some of the gluten.
There have been some misinformations flying around over the past few years that sourdough bread is gluten free, or can enable people who haven't been able to eat gluten, to add it back into their diet.
While sourdough can be gluten free if made with gluten free flour, the statement that sourdough made with wheat flour is gluten free is an absolute myth.
Please note this post is general information only and cannot be taken as medical advice. If you have a medical condition or are wanting to change your diet, please seek professional advice.
Is There Gluten in Sourdough Bread?
If you have made sourdough bread with wheat flour there will be gluten in your bread. However, the amount of gluten in sourdough bread will be less than regular yeasted bread.
Gluten is a group of proteins that can be found in grains like wheat, spelt, rye and barley. It is this group of proteins that help your dough become stretchy and elastic. Gluten is also responsible for helping your sourdough to rise. You can read more about gluten here.
A strong gluten network is needed to support the gas bubbles produced by the yeast in your sourdough. If the gluten network is weak, the gas escapes, giving you a flat loaf.
You'll find that sourdough made with high protein (gluten) flour like bread flour will rise the most. Lower gluten flours like whole wheat and rye will typically produce a flatter loaf with a less open crumb, because the gluten network is unable to support the gas bubbles as easily.
Sourdough isn't typically gluten free but it does contain less gluten than regular bread because of the fermentation process it goes through.
How Much Gluten Is There In Sourdough Bread?
Sourdough bread contains much less gluten than regular yeasted bread due to the fermentation process.
Regular yeasted bread contains around 124,000 ppm of gluten (source). That's pretty huge! But sourdough is not gluten free and still contains upwards of 200 ppm - even after a long fermentation period (source).
Now this is a huge reduction, however it's still not enough to be considered gluten free.
To be considered gluten free, food needs less than 20 ppm (you can read about this in detail here).
So while sourdough bread may be more easily digested by most people, it's still unsafe for people with celiac disease. And it could still be inflammatory for those with gluten intolerance.
Why Is Sourdough Bread Lower In Gluten Than Regular Bread?
Sourdough bread is made with a sourdough starter. A sourdough starter is a symbiotic colony of bacteria and yeast.
While the yeast are producing gas which gets trapped inside the gluten network of the dough, the bacteria are trying to break that gluten network down. The bacteria ferment the starches in the flour and it's this process that degrades the gluten.
It's for this reason that there is a fine line between well fermented and over fermented bread.
While longer fermentation periods can make sourdough bread more gut friendly, they can be detrimental to the rise and spring of your bread because of the eventual total breakdown of gluten.
Sounds complicated, right? But what here's a summary of what you need to know:
- "Good bacteria" (lactobacilli) neutralise the undesirable phytic acid in the wheat's bran making the nutrients in sourdough more bio-available to your body.
- The bacteria in your starter produce lactic acid, the yeast produce carbon dioxide. The carbon dioxide is trapped inside the strong gluten network, while the lactic acid is degrading the gluten.
- You need to balance the fermentation to get good oven rise with lower gluten - it's a definite balancing act!
How To Make Sure Your Sourdough Is Lower In Gluten
While sourdough is naturally lower in gluten, there are a few steps you can take to make sure your baked loaf contains less gluten than regular yeasted bread:
- Using less sourdough starter will mean you need a longer bulk fermentation.
- Longer cold fermentation (proofing) will give the bacteria more time to break down the gluten. Ideally, keep your sourdough in the cold fermentation process for at least 24 hours.
- Substituting some whole wheat or rye flour for some of the bread flour in your sourdough will give your loaf an overall lower gluten levels. This sourdough rye bread is a good example of this.
Why Is Sourdough Bread Easier To Digest?
Sourdough bread is easier to digest because of the fermentation process that it goes through. It is also lower in phytic acid and fructans than regular yeasted bread.
It is because of this that you may find you get less bloating and digestive upset with sourdough bread.
The Lactobacilli or good bacteria contained in your sourdough starter are fantastic for your gut microbiome! It's these bacteria that neutralise the phytic acid in the wheat's bran. This makes all of the nutrients in sourdough bread more bio available for your body.
Fructans can also cause digestive discomfort. Sourdough bread has no fructans once it's gone through the fermentation process. This makes it a safer choice for people who are trying to avoid fructans on a low FODMAPS diet.
Is Sourdough Bread Ok For Gluten Intolerance?
While sourdough bread made with wheat flour is unsafe for people diagnosed as celiac, it may be ok for those with a gluten intolerance.
Unlike celiacs, people with a gluten intolerance may be able to consume longer fermented sourdough breads or those made with lower gluten flour like rye.
If someone with celiac disease eats food containing gluten, an auto immune response is triggered and their system attacks its own body tissue. If someone who is gluten intolerant eats gluten, they may get short term bloating and belly pain - but it will cause long term damage.
You can read more on the differences between diagnosed celiac disease and gluten intolerance here.
The long fermentation of sourdough bread breaks down the gluten and will allow some gluten intolerant people to consume it without issues.
If you are celiac, you will need to make a gluten free sourdough starter to make gluten free sourdough bread.
You will need to exercise caution with sourdough discard recipes as some of these will contain unfermented flour which could cause issues for gluten intolerances and gluten sensitivities. You can read more about how to decipher sourdough discard recipes here.
Does Fermentation Break Down Gluten?
Yes, the fermentation that occurs in a wheat based sourdough starter and bread does break down gluten. But it does not eliminate it altogether.
This means that sourdough bread is not safe for celiacs unless it has been made with gluten free flour.
It can be ok for gluten intolerant people as it will contain much less gluten than regular bread.
The flour you use, the process you use and the type of starter you use will all have a bearing on how much gluten is left in your sourdough bread once it's baked.
Is There Gluten in a Sourdough Starter?
Yes - if you are making a sourdough starter with wheat flour then your sourdough starter contains gluten. The gluten in the sourdough starter is what allows your starter to rise.
The gluten network forms (just as it does in sourdough bread) and it allows the gas produced by the yeast to be contained. As the gas expands, the sourdough starter rises.
After a period of time, the gluten network is broken down by the bacteria in your sourdough starter. Eventually the gluten becomes so weak that the gas escapes from the starter, causing it to fall back down.
The fall signals your sourdough starter needing to be refreshed or fed.
Of course you can make a gluten free sourdough starter by using gluten free flours like brown rice flour, buckwheat or even a ready made gluten free blend.
You cannot use a wheat based starter to make a gluten free starter because you will be adding gluten to the gluten free flour. This contamination can be dangerous for someone who has celiac disease.
Frequently Asked Questions
Does sourdough have less gluten than regular bread?
Yes sourdough does have less gluten than regular yeasted bread. Sourdough goes through a long fermentation period whereby the lactobacteria in your starter start to break down the gluten in the flour. This results in a lower gluten level in your baked bread.
Is rye bread gluten free?
Rye bread is not gluten free. Rye bread will have lower gluten levels than sourdough bread made with bread flour or whole wheat flour, but it's not gluten free.
Why do some people add gluten to their sourdough bread?
Vital wheat gluten can be added to some flours that have a lower protein to make sure that they give a strong gluten network. Lower gluten flours like whole wheat and rye can benefit from vital wheat gluten. You should not use vital wheat gluten if you are making a gluten free sourdough or if you are trying to reduce the gluten levels in your sourdough bread for gluten sensitivity.
Is sourdough bread vegan?
Traditional sourdough bread made from flour, water, salt and sourdough starter is vegan friendly yes. You will need to check other types of sourdough bread because other types may contain butter, milk, cream and eggs. For example many soft white sourdough sandwich loaves will contain milk or milk powder and sometimes eggs for a softer crumb. You can find a full guide to making vegan sourdough bread and vegan friendly ingredient substitutions here.
I heard that an older sourdough starter will take all the gluten out of my sourdough, is this true?
No - no matter how old your sourdough starter is, if it's made with wheat flour, it will never be gluten free. The only way to make a true gluten free sourdough bread is to use gluten free flour with a gluten free sourdough starter. The fermentation process that your sourdough bread goes through will reduce the gluten in wheat flour, but it will never completely eliminate it.
Please note this post is general information only and cannot be taken as medical advice. If you have a medical condition or are wanting to change your diet, please seek professional advice.
