When I started making Greek yogurt, I lived in western Washington state and never, ever had an issue. Now that I've relocated to SoCal for work, every batch of my yogurt turns out awful (barely any effect from the starter, just runny) and I am making it the exact same way with the same materials. It's not been hot here so I can't figure out what the difference is. The climate here is definitely different than in Washington state.
Has anyone else had or heard of such a thing?
My yogurt making process is to heat the milk to 180, heat water for the cooler, bring temps of milk and water in cooler back down to about 115, then let the jars sit for 6 hours in cooler, then 6 hours in fridge and drain.
I am using the same brand of store bought starter (Fage Greek yogurt). Everything is the same except the pot I'm heating the milk in. I used to have a non-stick Calphalon pot I'd use, but now I use a stainless steel Calphalon pot. I have always done 6 hours at least in the cooler and never had an issue. This past time I let it go longer as I like to let it sit in the cooler overnight, but it still failed. I have not tried checking the temp of the water at the end of the procedure.
The tap water is incredibly harsh here (smells like chlorine even after being filtered so I buy water to drink) and leaves white residue behind on dishes after going through the dish washer. I boil my jars in this water but have never noticed the residue. Could the water be part of the problem?