Berliner (or not...)

It's Fastnacht weekend, I did not have a single Berliner yet and in the afternoon I decided to bake some.

I had no fresh yeast at home, so used a vegan dry yeast I found in the depths of the kitchen cabinet.
So far, so good.
The dough was fine, doubled in size; I formed the Berliner and the little flat braids. But then they wouldn't rise again. I gave them time and more time, covered them up with a kitchen cloth, more time. They would not rise, should have been three times the size when I gave up and deep-fried them. Perhaps too cold in my kitchen? Taste ok, but nothing more. 

19:20; 9°C