I had that same thing happen to me.
In the spring everthing was coming out good. Summer came and my programable thermostat on my house would let it get up to 80 during the days. I had a bad batch with the same symptoms.
Now I have a freezer with a temp control in the garage and back to good beer.
New guy question
I am having problems getting the stopper to seat and stay put.
I am using starsan and when I push the stopper in it will immedietly push itself back up. everything is too slick. One batch that I had trouble with pushed the stopper out over night.
I have been leaving...