Hi guys,
So I made my own culture 3 or 4 weeks ago, and I was very proud with it; since then I made, in this order: bread, pizza, pretzel, naan, croissants, donuts. Whereas the 1st test (bread) was ready in 5H, these two last tests' fermentation didn't succeed very well.
I started the culture with 25g rye flour and 25g bottle water. Left it 24H @23~25°C. It was dry, and no fermentation sign. I thought it didn't work, but I kept it, left it one more day - still nothing, then fed it with 25g rye and 25g water, 24H more, and still nothing. I thought maybe it's too dry, I added a little bit of water. The day after, there were some tiny bubbles. Yeaaaah! It started to work!
I fed it with regular flour (I have around 15kg of a Russian flour that a friend gave me, not suitable for pizza) (very strange flour by the way, it's written 13% protein on the label, but behaves like a 8% one..). And it started to be quite active.
Another feeding the day after, and it rose, more than double, within 2H (put the container on the floor, I have a floor heating system, 28-29°C).
I made bread with 30% sourdough (from the total weight of dough, not from the flour), and it was ready within
5H, I have a very good result. I made 2 tests, one using sourdough before feeding, and one after feeding, both were successful.
Rather than keeping feeding everyday, I decided to put on the fridge. I guess I fed it every... 3 or
4 6 days. And during the latest tests (croissant, donuts), it seemed the dough didn't rose as before.
But it's only yesterday that I realized there was a problem: I fed it the morning (always half flour/half bottle water), and the afternoon there was only a few bubbles. Left it at RT overnight, and this morning it seemed to have more bubbles, so I decided to feed again right away, but when I put a spoon in it I could tell that the structure was not like before (less bubbles inside). I fed it, and put it on the floor, it's been 3H but nothing happened...
What did I do wrong?? Why isn't there more activity now?

(first pic is SD I just took, the 2 other are how it looked like 2 weeks ago)