I have been making this recipe for a few years and it always turns out but it hasn't in the last week and I'm trying to figure out why.

Recipe:

600g flour or 550 and some sourdough discard

10g pink salt

30-45g sugar or honey

337g buttermilk or milk

10g instant yeast

2tbsp butter or olive oil

I knead in my mixer until windowpaned, around 10 minutes, rest in bowl one hour but I've shortened to 45 minutes as well with the same result. I roll into bread pan and rest 1 to 1.5 hours depending on how it looks. This one was 1.25 as it started to look flat so I thought it was over proofing. My husband thinks it's too cold (about 5 degrees less than usual as it's cooling down and we've stopped with the central air). I thought that since my Brötchen recipe also didn't rise in the oven that I killed my yeast. I've baked this loaf 4 times and my Brötchen recipe once and none of them have risen in the oven. But this loaf is new yeast.…