Am I overheating my starter?
I recently got a thermostat controller and a heating pad to use for starter maintenance and dough proofing. This helps a lot in cold Edinburgh winter, however as everything, there is a learning curve.
My setup is very simple: heating pad on the bottom, then a piece of cardboard (optional) so I don't place the starter directly onto the heating surface, all inside a cardboard box. And the temperature probe, which I have been unsure about where to keep inside the box: temperature it reads when on the bottom (either directly on the heating pad, or on the cardboard on top of it), or somewhere in the upper part of the box are quite different - for example, 28C on the bottom, and 23-24 on the top. So I finally decided to just attach it with tape to the side of the box in the upper third, and set to 24C. But actually it seems that this causes the heating to almost never switch off.
Yesterday and today I was building a 2-stage bread flour levain from a refrigerated rye starter: first overnight approx 1:2.3:2.3 (doubled by morning - a bit low ratio for overnight, but the starter was not super active, so I thought I'd give it an easier time), then 1:1:1 for a quick build planning to mi the dough in early afternoon. When I was making the second stage I thought the starter seemed a bit different than usual, more liquidy. I thought maybe it overfermented a little, but it didn't look like it had peaked and fallen. But then the second build still hasn't doubled in 8 hours. The slow growth got me worried that during the day my proofing setup is overheating it, which would be in line with more liquidy consistency than normal. While during the night it's a little colder in the flat, and maybe it's not too hot for the starter. But I also measured the starter temperature directly around 3-4 hours after feeding, and it was between 27 and 28C. I repeated the measurement just now and got 28C exactly. That seems like a good temperature. It is possible that the layer on the bottom is warmer though. Could it be a problem? Is this too warm?
Should I change anything in my "proofer" setup? Probably, getting a fan would be beneficial, but then I also need a more insulated box :)
For now I simply turned down the temperature setting to 23C instead of 24C, since it seems then the heater sometimes comes on, and sometimes comes off... So less chance of overheating, I guess, but still stays warm.