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20200531 Sour CLAS Bread

Yippee's picture

20200531 Sour CLAS Bread

To learn more about concentrated lactic acid sourdough (CLAS), please see here and here




Lance and Pul had asked me how acidic the bread made with CLAS is.  My answer: It depends.   One can create aromatic, full-flavored, but mild-tasting loaves by using a small amount of CLAS.  One can also make sour bread by manipulating the amount of CLAS used, temperature, timing, and ingredients. And the critical control is straightforward--the temperature.


Because all the sour loaves I previously made with CLAS contained a high percentage of rye, to compare apple to apple, I used only wheat flour in this bake to experiment.  What I made was the mild-tasting Ukrainian loaf that I had made before.


The plan of this bake was:




30% Beehive AP

50% water


Main dough


67% Beehive

10% water (I forgot to add the remaining water, so the bread ended up with a 50% hydration)

2% salt

0.8% dry yeast




Preparing the pre-dough the night before, the pH of the mixture was 5.1.






After ~ 10 hours @ 30C/86F (it might have been ready in less than 10 hours, but I wasn't checking in the middle of the night), the pH dropped to 3.7.






pH 4.7 - fully-fermented main dough after about three hours @ 31C/88F - 33C/91F ish.






The 50% hydration loaf had less volume than the 60% hydration loaf.






The crust was more crackly because of the lower hydration.






This loaf had a much stronger and long-lasting tangy aftertaste than the one made without pre-dough. One can easily create a sour loaf with CLAS by playing with the variables. 









Bread1965's picture

HI Yippee - Looks good and interesting experiment.

But what's CLAS?

And I"m surprised by how warm you kept the dough for so long without over-fermenting the dough. 


Benito's picture

Very nice bake Yippee!


Yippee's picture

Thank you, guys!

Bread1965:  I may not have clearly described my procedures in my post. The fermentation time was about two hours, and altogether it took me about three hours to make the bread. So, the fermentation time was not that long.  CLAS stands for "Concentrated Lactic Acid Sourdough." I just learned about CLAS recently from a Russian baker, Rusbrot.  He demonstrates how to use CLAS in breadmaking on his Youtube channel and explains the science and the benefits of this fantastic technique on Blogger.   Rus is a friendly and knowledgeable baker.  He will answer any question about bread (especially rye bread) that you may have!




pul's picture

I started playing with the method, built some CLAS following the instruction on RUS's blog, and had a 1st bake. My first observations are that I have not seen much difference in flavor as compared to a conventional yeast bread. There could be several factors. First the CLAS quality I produced may not be good enough, second the CLAS amount used in the dough preparation was not high enough, and third my method to prepare the dough could be plain wrong. I have actually produced a conventional poolish but added the CLAS only during the final dough mixing, as opposed to your method which adds CLAS in the pre-dough preparation. I do not have any pictures to show, so I will have another run some time later and do some documentation.



albacore's picture

CLAS making worked a dream and I made a rye/wheat loaf. I thought the flavour was OK, with some lactic (yoghurt type) flavour, but a lack of acetic sour flavour. I think this is inevitable because the high temperature used to make CLAS favours lactic rather than acetic.

Perhaps it would be possible to also add some sourdough levain to the mix to get some sour flavour in?


Yippee's picture

Hi, Lance:

According to Rus, by creating a pre-dough with lower hydration and long fermentation time, one can get more acetic acidity with CLAS in rye bread. 70% hydration results in more acetic acid at 28°C. Maybe you can manipulate the rye flour in your dough to achieve the result you want. I noticed that the cherry chocolate bread I made last time was the tangiest of all the white loaves I made with CLAS, even though I didn’t do it on purpose. I guess it was because I used whole rye CLAS and rye flour in the dough.

To produce more of the acetic acid flavor in my experiment, I probably would lower the temperature and let the dough ferment longer to a point where it does not degrade.

If I were you, I would not add levain to the dough if I am already using CLAS because it means more work! You know that I have been trying to reduce the hassle of baking so that I can enjoy it more. Having to maintain a levain defeats the purpose of using CLAS!