I use digital temperature sensors. I do not let glass near my beer either. I ferment in Sanky kegs now. It is much better for safety.
Fermentor 1: Bill's House Ale II, Fermentor 2: German Helles, Fermentor 3: Bill's Schworzbier (Black Bier)
Tap 1: Bill's House Ale II, Tap 2: German Hefewizen, Tap 3: Nut Brown Ale
Future Brews: Stone IPA Clone, Blonde Ale, Budvar Clone, Newcastle Clone
New toy: Blichmann 27 gallon fermentor
If you find yourself in a hole, the first thing to do is stop digging
Good judgment comes from experience, and a lotta that comes from bad judgment