Audrey's First Child Grows up. Somewhat.

From what's left of the 400ml of starter, add another 200ml of water with 2 teaspoons of yeast, 2 teaspoons of your favorite sweetner, 2 teaspoons of salt, and flour to make a dough, about 250g flour, 50g of rye is also not bad and stir untill everything is moist. Work in a little more flour if you need to after a 30 minute rest. Knead for about 10 minutes and let it proof. The yeast will take over the rise and have it up in 2 to 3 hours. You can leave it out on the counter top and do some folding every half hour until you are ready to shape it. Cover with a large bowl to prevent any drying while working and proofing. Plop onto parchment and wait for a final proof (1 to 1 1/2 hours room temp). Slash deeply and bake in your preferred method. 400°F for about 35 minutes or until done. It would be a shame to waste a good poolish.

I'm still thinking about what's going on....

Chilled with Mom.... to answer the chilled feeding Q: First let Glen peak, I mean after he is chilled and you have time to watch him (the first 6 hours will not show much) stir him a bit & let him just rise and rise until he starts to fall down in the beaker. This will check his holding power. I'm hoping we get more lacto beasties and they can all hold hands and rise higher together. Once he starts to fall let him sit an hour and then build him for a recipe.

Mini O

Pat,

I don't know if this is true, but I wonder if there isn't a whole category of "high acid" starters.

If you read about the behavior of cultures composed of Lactobacillus sf and C. Milleri  (the lactobacillus bacteria and yeast strains found in many sourdough cultures studied and written about in a number scientific papers - Ganzle the author of some of the ones that were to me most informative), you would quickly come to the conclusion that your method should not work. The acid is never sufficiently relieved at such a low feeding ratio. In fact, cultures maintained with low feeding ratios have been found to have much lower quantities of Lactobacillus compared to yeast, relative to those maintained with higher feeding ratios. The reason is simple: L. sf bacteria do not grow below a pH of about 3.8 and stop producing acid and start to die below about 3.6 pH. So, clearly if you maintain a culture with little or no acid relief, which is what happens with feeding ratios below about a doubling of the culture at each feeding, then the yeast can survive, but their partners in crime, the L. sf bacteria, will begin to drop out of the culture.

So, why does your method work?

Ganzle also says there are cultures continuously maintained at low pH, and they have different more acid tolerant Lactobacillus strains in them. In particular, he mentions L. pontis as a strain that is found in continously fed cultures in industrial "culturing machines". He suggests that cultures that are routinely maintained at low feeding ratios will eventually become populated by acid tolerant Lactobacillus bacteria, such as L. pontis.

I've noticed any number of participants on TFL who protest that their cultures work well over long periods of time maintained with very low feeding ratios. I remember Brotkunst, who I haven't seen posting in a while, described feeding his culture at a very low ratio and high hydration and keeping it continuously in the refrigerator, which shouldn't be a good culturing strategy if you think you are culturing L. sf.  Yet, he was doing this over a long time, and he was obviously making very nice bread with his culture and was satisfied with the flavor of his bread.

So, if you divide the sourdough culture world into to groups, one composed of those who have cultures similar to L. sf and C. Milleri, and others with cultures that have a more acid tolerant strain, like L. pontis along with whatever yeasts might naturally live alongside L. pontis in more acid conditions, you can begin to understand the sometimes conflicting accounts of how to maintain a culture.

If you're culturing a L. sf or similar bacteria, then you need to feed at ratios that at least triple the culture, if you are going to raise the pH enough at each feeding to allow the L. sf to regenerate themselves sufficiently to have a stable culture.  However, if you are culturing L. pontis, then you would maintain the low pH, and therefore feed at very low feeding ratios, to avoid an invasion of other less acid tolerant strains.

As far as feeding frequency for either of these methods, I believe it is a function of the feeding ratio and the temperature, and is variable over a wide range depending on those factors. If you do what I do, which is a relatively high ratio of 10:1 new culture to old, e.g. I feed 20 grams water and 25 grams flour to 5 grams of starter,  then at a warm temperature around 80F it works well to feed about every 12 hours. However, at cool temperatures around 65F, every 12 hours would be too frequent. The culture needs longer than 12 hours at 65F to completely populate the 10 fold increase in fresh flour introduced during the feeding. On the other hand, if you feed 1:1:1 by weight of (starter:water:flour), tripling your culture each time, then feeding a minimum of every 12 hours makes sense, especially if the temperatures are warm. In fact, if feeding at a ratio of 1:1:1 at 80F, by the time 12 hours has elapsed, the culture would be past the point when it might have optimally been refed.

Your strategy is very interesting, using a 45F temperature for storage, which may be just enough to have some very slow growth, and then doing occasional warmer refreshments at very low feeding ratios. I would assume you must have the more acid tolerant strain of Lactobacillus bacteria in that culture.

So, what would happen if I started managing my culture as you do and you started managing your culture as I do? I would imagine the cultures might both go through a period of instability as different strains of Lactobacillus become established. In my case, the L. sf-like bacteria that probably lives in my culture would be under tremendous stress from the continuously low pH if I started maintaining mine as you do. However, hopefully at some point a more acid tolerant Lactobacillus would establish itself, and I'd be OK from there on out.

In your case, I don't know if the L. pontis-like bacteria would still thrive if maintained at a higher pH using a higher feeding ratio, as I do. Maybe the less acid tolerant strains like L. sf have an advantage over L. pontis at higher pH, higher feeding ratios, since L. sf is what is commonly found in cultures maintained using feeding ratios of more than triple. If so, I would imagine after a time, if you used my feeding routine, the L. pontis-like bacteria would drop out, and L. sf-like bacteria would establish themselves. I wonder if the culture would go through a period of difficulty during the transition from more acid tolerant bacteria to less acid tolerant bacteria.

Bill