June 12, 2024 - 7:04am
Sourdough Starter Issues: Decreasing Volume Increase Over Time
I attempted to create a new starter with 50g each of flour and water. For the next cycles I used a 1:1:1 mixture taking 50g of the last cycle result. I used organic rye flour for this. I mixed the ingredients with water at 36°C (97°F) and let the sourdough ferment at 27°C (81°F).
For the first 3-4 cycles, everything worked perfectly. I achieved a doubling in volume and fed the starter accordingly. However, during the 4th cycle, I only saw a 1.8x increase in volume before the growth stopped. By the 5th cycle, the increase was just 1.4x, and by the 6th cycle, there was practically no volume increase at all.
What am I doing wrong?
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Maybe nothing. Activity during the first days or more is not going to be from yeast, it's going to be caused by unwanted or even harmful bacteria. As the mixture gets more acidic over time, those organisms get progressively suppressed and the apparent activity decreases. In may even seem to stop altogether, but the mixture will still be acidifying. Eventually the yeast and desired bacteria prevail and you start to get the activity you are looking for. You might not have gotten there yet.
OTOH, that's an unusually high temperature to be incubating a new starter. Why so high? It will change the usual relation of yeast and LAB concentrations. Also, purely rye flour may be low in yeast concentration (but high in LABs). It could be worth adding some whole wheat or even all-purpose flour to the mix.
Feeding too often, especially near the beginning, can be counter productive. The yeast concentrations are low then, and by feeding too often you could dilute them faster than they can grow.
TomP
Thank you for your insights! I wanted to add some more details and ask for further advice.
Flour Type: I am using whole rye flour (Vollkornroggenmehl), which I forgot to mention initially.
Temperature: The 27°C (81°F) incubation temperature comes from a German book by Lutz Geißler (Brotbackbuch Nr. 4). Given that this might be too high, what temperature would you recommend instead? Is there a specific range that works better for whole rye flour?
Current State of the Starter: I haven't fed my starter for 1.5 days. Is there still a chance to save it, and if so, what steps should I take next?
I've only ever started an all-rye culture at room temperature, and I'm definitely not very knowledgeable on the subject. So I better defer to someone else on TFL who knows better. My wheat experience won't be as helpful.
Generally speaking, I would say it can be rescued. Could you say why you want to follow that book? Is this procedure intended for some specific kind of starter or bread?
I have been following a tutorial from a book by Lutz Geißler, who is renowned in Germany as the "Pope" of bread baking. Do you have any recommendations for a better tutorial or resource?
How long is the cycle? A new starter will take longer - as in weeks. Enjoy!
The first cycle was 24 hours, the second about 12 hours, and the third about 8 hours until doubling in volume.
The fourth and further cycles were about 10 hours before the growth stopped.
Wait till it gets thin before adding anything - however long it takes. Add enough to make it thick - and wait till it gets thin - however long it takes (it'll go faster once it's established). Don't rush it - it takes time. Enjoy!
Rye starters don't thin out like wheat starters do. I've got one that was neglected in my refrigerator for more than 2 months (probably three) and hasn't thinned out. I just fed it and am leaving it out on the counter to see how long it will take to wake up.
As Tom said it is normal for a starter to do this.
Feed your starter when it needs feeding and not according to the clock.
And so on...