This liquid crystal thermometer has an adhesive backing and it can be applied to your plastic or glass fermenters
for a fairly accurate look at your fermentation temperature. Reads 36 to 78°F. Which ever number is "green-est"
is your temperature.

Expert Tip Alert:  These don't do really well if they stay wet too long or come into contact with cleaning chemicals.
                                 Soooo, I never remove the back strip and I just lay the thing on my bucket lid or tape it to
                                 the side of my carboy, so I can remove it when it comes to cleaning time.