A couple of years ago, I wrote this blog post, where I explained how I built my own hydrometer using an Arduino and a distance sensor. A hydrometer is a device that allows you to estimate alcohol in beer, wine, and other fermented drinks.
In that post, I also highlighted some fascinating insights I got from ChatGPT—back when sharing ChatGPT conversations wasn’t the trend it is today. Yes, ChatGPT is a large language model (LLM) and outputs some amazing stuff, but let’s move on and see how it evolves over time...
At the end of my original blog post, I mentioned more sophisticated devices like the TILT hydrometer. This device not only measures the density of a liquid but also connects via Bluetooth to provide real-time readings. Surprisingly, the folks at TILT read my post and kindly sent me a TILT device for free!
To be honest, I hadn’t used the TILT for two years, partly because I hadn’t brewed beer since then. But it’s never too late! I decided to test it on my first mead—a fermented wine made from honey. Mead is incredibly easy to brew; you just need water, honey, yeast, and a bit of patience as it ferments over several weeks.
This time, I followed a simple mead recipe I found online and dropped the TILT into my fermentation jar. To my surprise, getting density readings from the TILT was incredibly easy. I downloaded their app from the iOS App Store, and it connected instantly—no pairing required. Even better, the device automatically activates when placed in the wort. Pretty neat!
Recording the density readings was straightforward as well. The mobile app allows you to connect to Google Sheets for data logging. However, to continuously record readings, your phone must remain in kiosk mode (i.e., the screen must always stay on with the app open). This could risk damaging your phone’s display due to ghosting effects from prolonged static pixels.
A better solution would be for the TILT to connect directly to Wi-Fi and send data to a configurable endpoint. Alternatively, you can connect the TILT to a Raspberry Pi via Bluetooth to continuously post readings online. Interestingly, the TILT uses Bluetooth Low Energy (BLE) and doesn’t require pairing to receive readings. It openly broadcasts temperature and specific gravity data, making it versatile and easy to integrate into custom solutions.
Leveraging AI, I created a script to read TILT device data directly on my MacOS. This bypassed the mobile app’s limitations and allowed me to collect continuous data for analysis.
The graphs below display the specific gravity and temperature readings over a 17-day period. The data follows an exponential decay pattern, which can be modeled using the following equation:
\[ SG(t) = FG + (OG - FG) \cdot e^{-k \cdot t} \]
Where:
- SG: Specific gravity at time \( t \)
- OG: Original gravity
- FG: Final gravity
- k: Decay constant
On day #2, there was a significant drop in specific gravity. This occurred after I shook my fermentation jar. I’m unsure whether the drop was due to the removal of accumulated bubbles around the hydrometer or if the TILT device was being misaligned or displaced by the surrounding orange wedges and raisins.
You can find the code for connecting to the TILT via MacOS, creating these graphs, and fitting the exponential decay model in my GitHub repository.
Here’s how my mead looks currently. I plan to give it another 2–3 months to further develop its flavor. Stay tuned for updates!