These OneWire temperature sensors are custom made and much higher quality than the ones you find on Amazon or eBay, the ones with the shrink wrap around the probe. We know, they cost a bit more than the cheap 5-packs, but they are worth it:

Unilke the cheap sensors, our sensors have:

• Silicone cables that can withstand boiling temperatures
• The temperature sensor all the way down into the tip of the probe
• The probe completely filled with epoxy, for guaranteed waterproofness
• An RJ11 plug (fits in RJ12 socket)

Specs:

• 1.5m cable
• 0.0625 ºC resolution
• Range of -55°C to +125°C
• Factory accuracy of ±0.5°C over the range of -10°C to +85°C
• With calibration via the BrewPi software, accurate to 0.0625 °C
• Probe diameter: 6 mm / 0.24 inch
• Probe length: 50 mm / 1.97 inch