RAPT Pill Hydrometer & Thermometer

The RAPT Pill is a wireless hydrometer and thermometer that floats in the fermenter and reports specific gravity and temperature while the batch works, so you can watch an attenuation curve without opening the lid to draw a sample.

It reports to the RAPT portal over wifi, or to a RAPT Fermentation Chamber or RAPT Temperature Controller over bluetooth. Bluetooth is the mode worth using if you own one of those. It draws far less power, the signal gets out of a fridge more reliably, and it lets the Pill act as the temperature probe for the chamber without a thermowell. It also opens up fermentation control on gravity and on rate of gravity change, not just on temperature. A charge lasts about five months on wifi, and more than two years on bluetooth alone.

The housing is what separates it from earlier wireless hydrometers. It splits at the midline instead of unscrewing at an exposed thread, seals on a double o-ring, and is moulded from BPA free Nylon 12 and polyketone, both food grade and resistant to heat and chemicals. The body is larger than most, which keeps hops, krausen and CO2 bubbles from throwing the gravity reading as badly. Solids stuck to the outside will still affect accuracy, so give the fermenter an occasional shake to wash them off and let them settle out.

Readings log to the RAPT portal, where you can build temperature profiles, review past batches and set email alerts if something goes wrong. There is no cap on how many RAPT devices you connect to one account.

Specifications

• Gravity accuracy: ±0.002 SG
• Temperature accuracy: ±0.2°C
• Temperature range: -20°C to 60°C
• Pressure: 0 to 5 bar
• Battery: Li-Ion 18650, charged through USB-C
• Size: 37mm diameter x 125mm long
• Supplied with a yellow top housing as standard, with the colour you select to swap in

Charge it for a full 24 hours before the first run so the battery is full and calibrated. To pick up a firmware update, connect it to USB-C and a 2.4GHz network at the same time. Browse the RAPT range for the temperature controllers and fermentation chambers it pairs with.