|Mature liquid sourdough|
I had the idea to write this piece while I was looking some feeds on Instagram and I figure that some people (either pro and home bakers) had the same problem with liquid sourdough.
The main issue was a lack of activity (or strenght) and a strange smell/flavor that was not typically related to sourdough. Since the acidity was good, (let's say around 3,8 to 4,2 ph), as well as proofing times and temps, the problem was obviously generated from some bacterias contamination. It's not quite easy for sourdough to be contaminated, but in some cases, even if one works with the right hygiene protocol it happens. If the levain have been suffering some stress, in example very long fermentations with either low starter inoculation and/or low temperatures (like in winter), the natural barriers from external bacterias may not work. Infact just the use of an organic flour which brings some different bacterias strains than usual can give problems of this kind.
What to do if refreshing after refreshing the issue does not solve?
The most secure (and drasthic) option is to toss the sour and make a new one from zero....
Obviously no one want to loose their beloved levain :)
Here is a method to try (with success most of the times) to bring back in strenght our sourdough.
First, we need to refresh it one time with this formula: 1:4:2 (starter:strong flour:water), mix it until a developed dough is formed (dough temp 25c) and let ferment 8 hours at 26-28c covered.
With a knife, cut the peel off and take only the heart of our stiff starter. Cut the center in 1cm slices and put them into a solution of 28c water with 0,1% white sugar for 15 minutes. (Water should be 5 parts greater than sourdough weight and 0,1% white sugar calculated on water weight). Be careful to not dissolve the slices in the water by using a gentle touch. Repeat the process, (refreshment and bath), until you loose the off flavor and solve the issue.
After that, the stiff starter can be converted again in liquid sourdough by proceeding with a couple (or three) feedings in which you augment the water %.
NB. this process can be used also for too acidic sourdoughs but not for yeasty ones.
Hope this will serve and I wish you many great "Natural Leavenings"
Ps. I found a transaltor for the book so it will be released quite soon in English ! :D