The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Sourdough & digestive health

bread10's picture

Sourdough & digestive health



I regularly make Spelt Sourdough bread and have been aware of the basics of how and why sourdough is a beneficial for better absorption and digestive health. However as someone with a compromised digestive system, I would like to have a greater understanding of how the different methods affect the results and make sure my weekly loaf is the most digestible that it can be.

I usually make one spelt loaf a week with the following recipe:

(Total ingredients)

100% White Spet (600g)

60% Water (350g)

2 % Salt


Leaven is 25% of four:

150g white spelt

75g water (50%)

7.5g Sourdough Culture (5%)


As you can see I only use a very small amount of culture to make my leaven and leave this at room temperature for 18-24 hours.

(Loaf - Ferment 1.5-2 hours > Divide > Proof 1.5-2 hours)


I'm interested to know how this approach affects the levels of bacteria/fermentation versus yeast?

and how does this method (in regard to digestibility) compare with other methods such as dough back method (I think that is the terminology) which uses larger amounts of culture?


I think I read somewhere that a loaf should ferment/rise for a total of atleast 6 hours to achieve optimal digestion. However I am aware that Spelt flour can not tolerate as long a ferment/rise as other wheat. My recipe is 1.5-2 hours ferment, divide and rise for further 1.5-2 hours and says not to go over this time as it begins to degrade. Is this long enough to achieve optimal digestibility?

In other recipe books I notice longer ferment/rise times, but I'm not sure if this is due to differences in flour or method. 


Also does sourdough fermentation completely eliminate the need to soak/sprout grain (to remove anti-nutrients such as phytates) prior to making flour? Can I get additional benefit from doing both?


I'm sure there are other things I may have missed, so any information, advice etc welcome.

Look forward to hearing from you - Thanks!


fancy4baking's picture

In fact i noticed great improvement in digestion ever since i started baking with sourdough. But on the other hand, there was a negative thing i've also seen with my mom who is diabetic. After eating whole wheat bread made with sourdough her blood sugar used to spike high. Then i read a brief article about this matter from a research conducted by Prof. Terry Graham from the Canadian Department of Human Health and Nutritional Sciences. Then i decided to convert from whole wheat to whole grain wheat which is available in abundance and supreme quality where in live. Surprisingly results changed quite drastically. Mom ate bread baked with whole grain wheat and sourdough and the results were as follow:

1- Blood sugar didn't rise as much as it used to do with whole wheat flour, and remained relatively balanced throughout the day. Also her urge for lunch relatively rich decreased for the favor of having very well balanced lunch, which supported her blood sugar level throughout the day.

2- As for digestibility, mom's chronice colon disturbances gradually decreased in recurrences and in severity, till they have become quite rare. Her nutritonist doctor attributed this to consumption of a wide range of yeasts and positive bacteria that sourdough accumulate, which help in boosting digestion considerably ultimately demenishing colon disturbances to rare occurance.

If you are interested you can refer to the brief report published by Prof. Terry Graham here

pmccool's picture

What's the difference between whole wheat and whole grain wheat?


fancy4baking's picture

Whole Wheat flour is white flour mixed with bran but with the germ removed. In some countries it is accepted to call Whole Wheat any kind of flour even if the germ is removed to a certain rate...i.e: in Canada if flour is made from wheat with 70% germ removed it is permitted to call the flour Whole Wheat. But definitely it is not Whole Germ, where the whole thing is milled withtou removal of anything of the germ.


don.sandersg's picture

That doesn't apply to the U.S. does it? Here, whole wheat is whole grain, right?

fancy4baking's picture

But i believe that the American Standard of Wheat Classification puts a quite distictively detailed categories for each kind of wheat and flour.

But generally speaking, i think that whole wheat flour in US contain no more than 75% of the whole grain as per SDWHEAT.

If interested to be educated about this matter, you can refer to the following link, pages 20-24

Farmpride's picture

nutrition of sour is a time based issue. unlocking the value in the grain is done by the addition of water and a slight acid, ie...vinegar or of course the sour starter as it has the acid too.  then letting sit for over X hours, or giving a long X hour fermentation. Simply adding the sour starter to a dough, giving the normal 1 hour ferment, then the bench time, then proof, is not enough time to do the job,  especially when using whole grain flours. for the most part folks eating whole grain breads (commercial) get no more and less than eating white bread but for the fiber. i can not say what the min X hours should be scientifically but i will state , as an opinion only... a 12 hour fermentation or pre soak is good.,, this should give you the same or similar results as the "sprouted breads" especially if one has used a starter or even little "Braggs Vinegar" ...most of my career i have been the "fast run low time" guy, as i do this as a living, and time is money... but now i am switching to the longer ferments for health, for my health and my customers.

i now am working with what is called an instant sour, a dried starter, and this also needs the long time to fully activate and do it's thing health wise,  it will lend the flavor in a short time dough, but it is nice to know that my body is getting all it can from what i put into it..right?


linder's picture

Hi all,

Alot of what is discussed here has been touted by the Weston A. Price Foundation with regard to the increased digestiblity of whole grains after overnight soaking or using sourdoughs.  It's interesting from a number of perspectives, health and well being.

Since using my own home milled whole wheat flour and sourdoughs, I notice that I am not eating as much and don't have the food cravings I do when using more conventional products.  Maybe it's just my imagination, but I'll keep on doing what I'm doing because it seems to give me more nutritious breads.


jcking's picture

One reason people eat and snack more is because their body is telling them there's not much good stuff in the junky food you're feeding me I need more. Another thing I find is some people don't drink enough water, coffee and soda don't count they're dirty water. Water flushes the system, good for kidney health, and helps move food thru the system. We need to communicate with our bodies and discover what it needs. Like home made bread, the more whole the better.



grind's picture

Recently I've been reading up on sourdough and celiac disease.  Interesting stuff from the digestibility of wheat point of view.

maggie664's picture

I'm interested to know whether or how sour dough, using all purpose white flour, changes its GI value. Thanks.

Moya Gray's picture
Moya Gray

I found this refernce for the GI of sourdough and rye breads

maggie664's picture

Thank you for reference Moya. So white four sour dough has just made the grade with a GI of 54!! Now to discover the food chemistry and physiology behind this. Am interested because my husband's blood sugar levels are border-line and we are using white flour sour dough GI as a marker.