December 5, 2023 - 10:50am
Adding diversity via fruits
Hi all,
I have been struggling to get my bread flour based starter really active. I have a rye-based one that is doing very well, but converting it does not yield a very active wheat starter. From all the research I have been reading, it seems that yeasts select for certain LAB and vice versa (This publication). This, in turns, means that is really important that the initial inoculation is. We also know that dried fruit contains a lot of wild yeasts, so my idea is to start sourdough with various bits of dried fruit. This paper compares dried longan with raisins and finds that the longan sourdough is raising dough much better.
My questions:
- If you have made your starter several times from scratch (just water and flour), how much variation have you noticed?
- Have you ever experimented with adding fruit or other plant material?
Thanks!
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Very little, as long as we stick with white wheat flour.
Yes. I made a new starter with white flour but added a large chunk of apple. The starter developed about the same as I was used to. When it was ready, it had a strong fruity smell but bread made with it rose the same as usual and did not have a different taste.
Over the next month or two the fruity smell gradually weakened and then disappeared. All that time the bread rose the same and had the same flavor.
The second paper is interesting but I don't think it has a lot of direct applicability to how most of us make and use starters. That's because they didn't include any wheat flour so we don't know how an equilibrium between species would have turned out.
It's also not the case the paper reported that "longan sourdough is raising dough much better." They only reported that they found more yeast in the longan sample than in the raisin sample. We don't know how effective those kinds of yeast cells and their concentration would be for making bread with wheat flour. And they did not have a "sourdough starter", IMHO, since it contained no dough and had not been used for making bread.
You may be interested in "CLAS" - Concentrated Lactic Acid Starter. You will find a lot of discussion here on the site by doing a search for the term.
TomP
@TomP: Fair points. I suspect that keeping the environment (and your hands) the same, you'd get pretty consistent results. I hadn't heard of CLAS, but that looks quite similar to type 2 sourdough, albeit with less fermentation time.
I kind of want the opposite though, a wheat sourdough with plenty of yeast activity. My former attempts all resulted in a sourdough with LAB totally overpowering the yeasts (the pH dropped consistently, but little gas was produced).
IIUC, Type 2 sourdough contains a specific yeast grown by a yeast supplier. Again, IIUC, CLAS contains only LAB, and not yeast.
Maybe it would be helpful if you said how you made, refreshed, and kept your starters.
Type 2 sourdough is LAB only, too (because yeasts are inactive at higher temp). I make my starter with Bob's bread flour, starting out at 1:1:1 every 24 hours for 2 days, then increasing to 1:3:3 every 12, with a target of 1:6:6. Kept at 23°C.
I stand corrected - though I have seen the term used to include yeast too.
If I kept my AP flour starter at that temperature for 12 hours, it would be way over-aged and maybe getting thin. I let it age until active and probably risen to max or near max, then I refrigerate it. I usually don't have enough LAB, the opposite of your problem.
That is exactly the opposite problem of what I’m having. If you have the yeast dominate it’s an easy fix - increase the temperatur, hydration or percentage of inoculum during refreshes.
Doing the opposite doesn’t quite work well once the LAB have taken over, but I’ll keep trying out new methods.
It hasn't been so easy for me. My culture is already at 100% hydration. I have tried aging after refresh at elevated temperatures in my proofer. None of these has really done the job. I can get it more acidic by not feeding it for too long, of course, but then it's not in very good condition for baking.
If the yeasts that grow on fruit are the same yeasts that populates a sourdough starter? I have a feeling they might be different. And even if adding fruit does help to give it a quick start at the beginning the yeasts that are more at home in a sourdough starter will eventually take over.
They can be. Michael Gänzle is one of the leading researchers in sourdough microbiology. He shares a story on Youtube on how some people even use horse manure during the incubation. Over time, competition will select the best adapted bacteria (most often LAB) and yeasts. Here is the relevant segment (starting at minute 26)
Now it gets me thinking about another question. Yes, they seem to favour different LAB depending on how they're started but do they still lose some lab/yeasts that come with the inoculate that can't take hold in a sourdough? In other words... sourdough cannot support every single type of yeast and bacteria, depending on what inoculate you use will affect the final outcome but only those that lab/yeast that can survive in starter will take hold. Is it limited or unlimited?
P.s. So many questions... who and why did anyone think about using manure?
Those are very good questions. At least from the first figure I posted, we can see that it was somewhat stable after 10 feedings. They also mention that older sourdoughs tend to have S sanfranciscensis which also aligns with their finding of it outcompeting many other LAB. But there is far too little research on long term equilibria.
S. Sanfranciscensis seems to be far more common then was originally thought.