A DIY Fermenter For Flavorful Brews

August 3, 2025 by Matt Varian 15 Comments

Fermentation is a culinary art where tiny organisms transform simple ingredients into complex flavors — but they’re finicky about temperature. To keep his brewing setup at the perfect conditions, [Ken] engineered the Fermenter, a DIY insulated chamber controlled by Home Assistant for precision and remote monitoring.

The Fermenter build starts with an insulated chamber constructed from thick, rigid foam board, foil tape, weather strips, and a clever use of magnets to secure the front and top panels, allowing quick access to monitor the fermentation process. The chamber is divided into two sections: a larger compartment housing the fermentation vessel and a smaller one containing frozen water bottles. A fan, triggered by the system, circulates cool air from the bottle chamber to regulate temperature when things get too warm.

The electronics are powered by an ESP8266 running ESPHome firmware, which exposes its GPIO pins for seamless integration with Home Assistant, an open-source home automation platform. A DS18B20 temperature sensor provides accurate readings from the fermentation chamber, while a relay controls the fan for cooling. By leveraging Home Assistant, [Ken] can monitor and adjust the Fermenter remotely, with the flexibility to integrate additional devices without rewiring. For instance, he added a heater using a heat mat and a smart outlet that operates independently of the ESP8266 but is still controlled via Home Assistant.

Thanks [Ken] for sending us the tip on this ingenious project he’s been brewing. If you’re using Home Assistant in a unique way, be sure to send in your project for us to share. Don’t forget to check out some of the other Home Assistant projects we’ve published over the years. Like a wind gauge, maybe. Or something Fallout-inspired.

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Big Chemistry: Fuel Ethanol

May 21, 2025 by Dan Maloney 73 Comments

If legend is to be believed, three disparate social forces in early 20th-century America – the temperance movement, the rise of car culture, and the Scots-Irish culture of the South – collided with unexpected results. The temperance movement managed to get Prohibition written into the Constitution, which rankled the rebellious spirit of the descendants of the Scots-Irish who settled the South. In response, some of them took to the backwoods with stills and sacks of corn, creating moonshine by the barrel for personal use and profit. And to avoid the consequences of this, they used their mechanical ingenuity to modify their Fords, Chevrolets, and Dodges to provide the speed needed to outrun the law.

Though that story may be somewhat apocryphal, at least one of those threads is still woven into the American story. The moonshiner’s hotrod morphed into NASCAR, one of the nation’s most-watched spectator sports, and informed much of the car culture of the 20th century in general. Unfortunately, that led in part to our current fossil fuel predicament and its attendant environmental consequences, which are now being addressed by replacing at least some of the gasoline we burn with the same “white lightning” those old moonshiners made. The cost-benefit analysis of ethanol as a fuel is open to debate, as is the wisdom of using food for motor fuel, but one thing’s for sure: turning corn into ethanol in industrially useful quantities isn’t easy, and it requires some Big Chemistry to get it done.
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The Briny Depths Give Wine An Edge, But How?

August 27, 2023 by Jenny List 61 Comments

Though Hackaday scribes have been known to imbibe a few glasses in their time, it’s fair to say that we are not a wine critic site. When a news piece floated by about a company getting into trouble for illegally submerging crates of wine though, our ears pricked up. Why are vintners dumping their products in the sea?

Making wine, or indeed any alcoholic beverage, starts with taking a base liquor, be it grape juice, apple juice, barley malt solution, or whatever, and fermenting it with a yeast culture to produce alcohol. The result is a drink that’s intoxicating but rough, and the magic that turns it into a connoisseur’s tipple happens subsequently as it matures. The environment in which the maturation happens has a huge influence on this, which is one of many reasons why wine from the cellar of a medieval chateau tastes better than that from an industrial unit in southern England. The Californian company was attempting to speed up this process by leaving the bottles beneath the waves. Continue reading “The Briny Depths Give Wine An Edge, But How?” →

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!

Make Your Own Vinegar

August 26, 2022 by Danie Conradie 32 Comments

Making fermentation work for us is one of the original hacks that allowed humans to make food last longer, and festivities more interesting. [Mike G] has been experimenting with making his own vinegar, and found the end product to be a delicious addition to his cooking.

The first step is similar to making alcoholic beverages. Take something that contains sugar, like fruit, mix it with water and let stand. Wild yeast will feed on the sugar and create alcohol. Once the alcohol content reaches the 6-12% range, the resulting liquid can be separated from the solids and left exposed to the air. This allows Acetobacter bacteria to convert the alcohol into acetic acid, producing vinegar. The entire process takes around 30 days.

[Mike]’s first round of experiments was mainly with fresh fruit, with the addition of raisins. To prevent white mold from forming the mixtures should be stirred daily, but life got in the way and mold got out of control on all the fruits, except for the raisins. This gave [Mike] the to try another round with dried fruit, which was significantly less prone to mold, and produced deliciously flavored vinegar. [Mike] also demonstrated their use in a couple of mouth-watering dishes.

The DIY vinegar production process is just begging for some fermentation monitoring and automation tech. We’ve seen plenty of sourdough and beer production projects, which we suspect could also be applied to vinegar production with some minor changes.

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They Milk Cows, Don’t They?

October 18, 2021 by Kristina Panos 90 Comments

You’ve no doubt heard of the many alternatives to cow’s milk that are available these days. Perhaps you’ve even tried a few of them in your quest to avoid lactose. Some coffeehouses have already moved on from soy milk, offering only oat or almond milk instead of 2% and whole. Their reasoning is that soy milk is a highly processed product that can’t be traced back to a single source, which stands in stark contrast to all those bags of single-origin coffee beans.

These nut-based alternatives kicked off what is known as the milk wars — the dairy industry’s fight against labeling plant-based dairy alternatives as ‘milk’ and so on. Well, now it’s getting even more interesting. A company called Perfect Day is making milk using microorganisms that secrete milk proteins. It may sound kind of gross, but it’s essentially microbial fermentation, which is the normal process by which bread, cheese, yogurt, wine, and beer are made.

To be fair, what Perfect Day and other companies are doing is precision fermentation using genetically engineered microorganisms in a bioreactor, so it’s a bit more involved than what you could probably pull off in the basement. Precision fermentation lies somewhere between two modern extremes — plant-based meat and cultured meat. The latter is actual animal tissue grown from stem cells, and is only available at high-end restaurants for exorbitant prices.

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Fermenting Yogurt With The Help Of Hardware

September 26, 2020 by Lewin Day 15 Comments

Fermentation is a natural process that has been exploited by humanity for millennia. Behind such favorites as cheese and beer, it takes just the right conditions to get the desired results. To aid in this process, and to explore the crafts of their ancestors, [Victoria] and [Petar] created an electronic fermentation quilt.

Bulgarian yogurt was the tasty end result from this work.

Anyone familiar with breadmaking will be familiar with throwing a cloth over dough when left to rest. This is all about temperature management, providing optimum conditions for the yeast to work their magic. This fermentation quilt takes things to the next level, integrating soft heater pads and temperature sensing hardware into the fabric itself. Rather than acting as a simple insulator, the quilt can actively supply heat where needed, switching off when reaching the set temperature. In this example, the quilt is set to maintain a temperature of 45 degrees for the optimum production of Bulgarian yogurt.

The fermentation quilt serves as an excellent example of what can be achieved when combining textiles with smart electronics. Tools like Adafruit’s Lilypad and conductive thread all come together to make this a functional and useful device, and shows that electronic textiles aren’t just limited to blinky wearables.

Fermentation is a popular topic among hackers, with [Trent Fehl]’s Supercon talk at the 2019 Supercon covering similar ground from a sourdough perspective. It goes to show that hardware skills can pay off in the kitchen, too!