I kind of just experienced a similar problem. I've had my keg ( first time kegger here ) in the fridge for the last 48 hours at what I thought was 38 degrees. Went out just now to drop the psi to 10 (from 30) and let it sit for a week. I discovered the water in the glass that I had the thermometer in to be completely frozen over and still reading 38 degrees. When I shake the keg, I hear a bit of liquid sloshing, but not much. I took it off the gas and out of the fridge. Can I just let it thaw, and return it to the gas in the fridge? And obviously turn the thermostat in the fridge down along with getting a new thermometer....
From the sounds of it, my beer will be fine?
Thanks!