Kombucha Monitoring System
My kombucha brewing hit a wall when I got tired of inconsistent results and decided to geek out on a solution. I built a custom monitoring system using a Raspberry Pi 3b+ as the brain, creating not just temperature and humidity controls, but a full database to track the progress of every batch. I wrote Python scripts for my Raspberry Pi Pico to handle the temperature regulation, while an ESP32 collects all the sensor data. I could then check on my brews through a custom interface I built and tweak conditions for the perfect batch.
Brewing Kombucha is one of my favourite hobbies. It’s a fermented tea where a thick, pancake-looking culture called a SCOBY transforms sweet tea into something tangy and bubbly. The whole process takes anywhere from a few days to weeks, depending on how strong I want the flavor to get, but the cold winters were ruining my brews. I've experimented with adding everything berries, fruits and herbs to create different flavors.
My kombucha monitoring system started as a simple project but quickly evolved into something complicated. Scope creep is a double edged sword. I started by prototyping with a DHT22 sensor for basic environmental readings, but soon added a DS18B20 for the precision temperature sensing. The real challenge came when I added a moisture indicator as an early warning system for bottle explosions during second fermentation. Programming the ESP32 to handle UART, I2C, and OneWire protocols simultaneously was my first real dive into C++, with plenty of late-night debugging sessions. What began as a simple "keep this vessel at the right temperature" concept grew increasingly complex and fragile. I found myself writing failsafes and data cleaning to ensure reliable feeds to my Grafana dashboard. Getting clean data properly formatted for Node-Red to insert into my InfluxDB time series database taught me more about data processing than I expected from a simple brewing project. Here’s how to do it:
How to (condensed)
1. Purchase high density insulating foam and a crate
2. Cut the foam to size, and line with reflective tape for added insulation. Install two light holders
3. Build a unit that takes sensor readings and sends them to a Raspberry Pi Pico, which then sends them to the Raspberry Pi 3b+ over MQTT
4. Build a Grafana Dashboard with integration to an InfluxDB time series database that displays current temperatures, humidity, heating cycles, and moisture sensing for any leaks or accidents
5. Obsessively check the system every 5 minutes to make sure it’s still working until fermented. There’s Kombucha on the line
6. Serve over ice