An Ian Lowe post on sourdough starters - always interesting, sometimes controversial, sometimes annoying, but most of this makes sense - even if Ian's rules are not easy to work to for home bread makers.
https://www.instagram.com/apieceofbread/p/DQiqGQpknsq/?img_index=1
Lance
Ian made a compelling case for these rules on his Instagram story the other day, and I think he plans to elaborate on his Substack soon. He says that refrigeration always damages the yeasts and LAB, and that continual warm (or at least ambient) refreshment differentiates bakery sourdoughs from discontinuous (home) bakers. That the peoplel who cold store SD in maintenance never get the kind of results that bakeries get, due to the vigor, stability and diversity of non-refrigerated starter.
He is only maintaining a stiff starter at this time, around 50% hydration, I believe.
It takes me back to reading about Gerard Rubaud's starter routine on MC Farine's blog; he refreshed 1/2/1 (or was it 1/1/0.5?) at 25C every 5 hours. I think the only longer duration was at night, where he gave himself an extra hour or two's sleep.
If only I could develop an automatic gadget to do it! Not easy at 50% hydration.
Lance
Before Ian started the production in his new business, he fed his stiff starter only once or twice a day with a 1:5 or 1:10 ratio, afair. Always 28ºC.
The inoculation ratio is very important because it changes the initial acidity.
If the (stiff) starter collapses or not is not relevant for the continuation starter.
Volume increase + collapse or not is just a matter of rheological properties. It has very little relevance for the assessment of the microbial populations (in a continuation starter!)
It seems intuitive that a starter is, in principle, a special-purpose dough in miniature and thus would be impacted by as many variables as a dough is. But there are few things here that make me muddled:
--it's hard for me to fathom how keeping a higher hydration starter could offer "less total acid" and at the same time "lower final pH"
--similarly, it's hard to fathom how using a higher extraction flour in a starter would offer "more total acid" and at the same time "higher final pH"
--Also, I wonder if these rules would apply just as much to a 100% rye starter as they do to wheat.
Rob
It’s actually pretty easy to understand. Ian explained this already in the past. And in the comments. Just read the comments.
as I'm not on insta (I got off social media a while back to preserve my sanity), I can't read the comments. -- Rob
Of course you can if you want. Just click on the link in the first post, open it in the browser, not in the IG app, close the dialog for login or registration et voila, you get the comments on the right hand side.
I also have no desire to have an Instagram or Facebook account. As you suggested, I used the link and closed the dialog box, and yes, the comments are visible. However, I cannot expand the comments to reveal his explanation of total acidity and pH. Can you post his comments for the rest of us?
Indded, I couldn't easily get my head round this - hence why I said the rules "generally" made sense.
So I resorted to CGPT and got this response:
"Why a higher-hydration starter can have:
1. Lower pH (more acidic “strength”)
High-hydration starters favor:
Homofermentative LAB (like Lactobacillus plantarum)
Faster bacterial growth
Faster sugar diffusion and fermentation
These LAB produce mostly lactic acid, which has a strong effect on pH (it dissociates readily and lowers pH).
More water → faster LAB activity → more free hydrogen ions → lower pH.
2. But less total acidity
High hydration also:
Speeds up fermentation but shortens it (they run out of sugars sooner)
Produces more lactic acid relative to acetic acid
Produces fewer total acids before the food is depleted
Low hydration starters (stiffer, like 50–60% hydration):
Encourage more heterofermentative LAB (like Lactobacillus brevis)
These produce acetic acid, which has a higher buffering capacity and counts more toward total titratable acidity
Acids accumulate more slowly but in greater total quantity
So a stiff starter may have:
Higher pH (less sharp acidity)
But more total acid present when measured by titration.
I'm not sure if that agrees with Ian's comments as I haven't re-read them yet.
Lance
Thanks. That clarifies things. I'm also wondering what the 'final' of "final pH" means -- final as in when the starter is at its peak or final as in when you might measure the pH of a fully mixed and fully fermented dough before it goes in the oven.
Rob
I think Lance has covered your questions but I wanted to add my own thoughts. The concepts of pH and total acidity (TTA) are hard to separate because both describe properties of acid "strength". It's complicated because the acids (acetic and lactic) found in dough are not "strong" acids like hydrochloric or sulfuric acid and do not fully dissociate when dissolved in water. For example, dilute acids of the same concentration (0.1 M) have different pH:
The way I think about it is pH measures only free H+ in solution. TTA measures all acids present: undissociated acids in solution, free H+ in solution, and H+ bound by dough. I still haven't found any definitive reference as to why whole grains allow for higher TTA. The buffering capacity of the whole grain is higher but I don't know what is binding the additional H+.
Another complication of TTA is that it is harder to measure than pH. It's possible to get a reasonable estimate of the pH of a starter or dough with pH paper, but TTA requires a titration and the associated chemicals. I also find it hard to determine the color endpoint of the titration because darker dough (aka "rye") interferes. A pH meter would solve that but I haven't wanted to buy one (yet).
Jeffrey Hamelman wrote (I don't remember if this is in his "Bread" or if he was quoted by Stanley Ginsberg in "The Rye Baker") that his students at the CIA were baking better bread than he was: they were feeding their starters daily and he was feeding his 3 times a week.
I do not doubt that daily feeds can result in great bread; I think you need a palate way better than mine to tell the difference between daily and twice daily feeds.
I'm happy with my weekly feeds, 12 hrs before I mix the levains/sponges. More important, my wife is happy with the results.
If you're not careful, a great hobby could turn into a chore.
Lance
And some people look for that. No harm in making things easy - no harm in making things hard. Go with what ya know and are comfortable with. Enjoy!