What is the Tilt Hydrometer?
The Tilt is a wireless hydrometer that floats inside your fermenter and reads specific gravity and temperature continuously — no need to pull samples or crack the lid to check progress. It broadcasts those readings over Bluetooth, so with the right setup you can watch your fermentation curve in real time from the Grainfather app.
Unlike the GCAST, the Tilt isn't a bridge — it's the actual sensor floating in your beer, doing the measuring.
Features & specs
- Continuous, real-time readings of specific gravity and temperature — no manual sampling
- Gravity accuracy: ±0.002 across a range of 0.990–1.120
- Temperature range: 0°F to 185°F (-17.8°C to 85°C)
- Temperature accuracy: ±1°F (±0.5°C)
- Bluetooth range: up to ~25 feet to your phone/tablet
- Compatible with: iPhone/iPad and Android devices with Bluetooth 4.0+
- Size: 3-5/8" (9.2cm) long, 1-1/8" (2.86cm) diameter — designed to fit a standard 5-gallon carboy as well as the GF30/G40 fermenters
- Works with: the Grainfather App, the GCAST (for cloud logging without your phone), or a Raspberry Pi running Tilt Pi software
What's included in the box
- 1x Tilt Hydrometer (in your chosen colour)
- 1x pre-installed CR123A battery (already fitted, ready to go)
- Quick start instructions
That's it by design — it's meant to be simple: sanitise, drop it in the fermenter, and pair via Bluetooth.
How it works
- The Tilt floats in your fermenter and continuously measures gravity (via its tilt angle — hence the name) and temperature.
- It broadcasts those readings over Bluetooth — it has no WiFi or internet access of its own.
- Something else needs to pick that signal up and get it online. Your options:
- Leave your phone nearby with the Tilt app open
- Use a Raspberry Pi running Tilt Pi software as a gateway
- Use a GCAST, which can pick up all 8 Tilt colours at once and push the data straight to the cloud — the easiest, set-and-forget option
Connecting it up
- The Grainfather app supports the Tilt directly, alongside other third-party fermentation trackers (PLAATO Airlock, Brewbrain Float, iSpindel, and custom webhook streams).
- Tilts can also be added via URL in the Grainfather app if you're setting up multiple devices.
- If your Tilt data isn't logging, the most common cause is the gateway device (phone or GCAST) losing its Bluetooth or WiFi connection.
Power
- Comes with a pre-installed battery lasting roughly 12–24 months, depending on how often it's used.
- When it's time to swap it out, it takes a standard CR123A battery — other brands work fine too, doesn't have to be the official one.
- Note: if you ever switch to a rechargeable battery, only LiFePO4 is suitable — other rechargeables run too high a voltage for the Tilt.
Why the Tilt reading doesn't always match your GF30 probe
This one catches people out, so worth knowing: it's usually not a fault, it's physics.
- The Cheerios effect — the Tilt naturally drifts to the edge of the fermenter. If your GC4 is running glycol at the time, the Tilt can end up resting against the cooling jacket, reading cooler than the actual beer temperature.
- Stratification — the top of the fermenter (where the Tilt sits) is more exposed to ambient air through the lid, while the GF30's probe sits lower, closer to the middle of the batch — the more thermally stable spot.
- Inversion during fermentation — cold liquid sinks, warm liquid rises. Active fermentation creates convection that keeps things roughly even, but when the beer's cold and less active, that convection slows and the two ends of the fermenter can genuinely be at different temperatures.
Bottom line: both readings are usually correct — they're just measuring different points in the fermenter.
Does it need calibrating?
Not through Grainfather — the Tilt is a third-party device, so calibration (if it ever drifts) is done through the separate Tilt app, not the Grainfather app.
Quick troubleshooting
Not logging data:
- Check the gateway (phone with Tilt app open, GCAST, or Raspberry Pi) still has power and a live connection
- Confirm the Tilt's battery hasn't died — a sudden drop-off in readings is the classic sign
- If using a GCAST, check its LED status (see the GCAST guide)
Readings look "wrong":
- A temperature difference from your GF30 probe is expected, not necessarily a fault — see above
- For a gravity that seems off, check the Tilt app for calibration options before assuming the unit's faulty