Fermenter on the desk, with the front door opened and some tempeh disks visible inside of it

Hackaday Prize 2022: An Easy-To-Build Fermenter For Tempeh

October 3, 2022 by Arya Voronova 18 Comments

[Maud Bausier] and [Antoine Jaunard] believe we should all know about tempeh — a traditional Indonesian food made out of legumes fermented with fungi. To simplify the process a bit: you get some soybeans, add a tempeh starter fungi culture to them, ferment them a while, and out comes the tempeh. It’s a great source of proteins that’s relatively easy to grow on your own. One catch, though — you do need a certain kind of climate to have it develop properly. This is why [Maud] and [Antoine] are bringing a tempeh fermenter design to this year’s Hackaday Prize.

This fermenter’s controller drives a heating element, which adheres to a pre-programmed fermentation cycle. It also has a fan for airflow and keeping the heat uniform.

The fermenter itself is a small desktop machine with a laser-cut case helped by some CNC-cut and 3D-printed parts, electronics being a simple custom PCB coupling a Pi Pico with widely-available modules. This is clearly a project for someone with access to hackerspace or fab lab resources, but of course, all of the files are on GitHub.

Once built, this design allows you to grow tempeh disks in home conditions on a small scale. It seems the design is mostly finalized, but if you’d like to hear news about this project, they have a blog and a Mastodon feed with some recent updates.

We’ve covered a whole lot of fermentation-related hacks over these years. Most of them have been alcohol-related, but every now and then we see people building fermentation equipment for other food materials, like vinegar, yogurt and sourdough. Now, having seen this fermenter, we’ve learned of one more food hacking direction to explore. This project is one of 10 finalists for our latest Hackaday Prize round, Climate-Resilient Communities. It’s a well-deserved win, and we can’t wait to see where it goes!

Logging Bubble Frequency And Pressure In Your Fermenter

October 24, 2011 by Mike Szczys 21 Comments

In an attempt to add technology to his brewing process [hpux735] build a sensor rig that monitors bubbles and pressure during fermentation. What does this have to do with brewing great beer? We’re not sure and neither is [hpux735], but he’s got some preliminary readings to spark your imagination.

The bubble sensor itself was inspired by a SparkFun Tutorial where fermenting wine was monitored with a data logger. It uses an optical gate to detect the passage of air. But the goal here was to combine bubble frequency with internal pressure measurements to calculate how much CO2 is being vented. Perhaps it would be possible to get an idea of how close the batch is to completion based on those calculations. A hole was drilled into the fermenter side of an airlock to take these pressure readings.

This actually works quite well during secondary fermentation when the bubble frequency is quite slow. The hardware is able to discern a pressure difference before and after a bubble has passed the lock. Unfortunately the system breaks down during the vigorous bubbling that takes place soon after pitching yeast. See a few bubble-counting clips in the video after the break.

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