Measuring Alcohol Content With Time of Flight Sensors

[Chris] is a homebrewer – the tasty kind – and wanted a way to track the rate of specific gravity against temperature. Tracking temperature is easy, all you need is a 1-wire temperature probe hooked up to the microcontroller of your choice. Logging the rate of fermentation isn’t as simple, but with a time of flight sensor, a hydrometer, and some pool toys, [Chris] kludged something together that works reasonably well.

Specific gravity, and thus fermentation, has been measured for centuries with hydrometers. Not wanting to complicate matters with electronic sensors, [Chris] built a floating cage for his hydrometer out of a clear tube, a kick board, and a few bits of styrofoam. By placing a Sparkfun time of flight sensor at the top of the tube, and lowering the hydrometer into his fermentation bucket, [Chris] can measure the height of the hydrometer above the level of the liquid in his fermentation bucket.

Both the temperature and specific gravity are logged to a Raspberry Pi, and after combing through this data [Chris] can see a big ‘bump’ in the specific gravity due to a mass of foam, tapering down to the desired values after a day or so.

Brewing Beer with a Sous Vide Cooker

[Ken] found an interesting use for his sous vide cooker. He’s been using it to help him with his home brewing. It’s unlikely that the manufacturer ever intended it to be used in this manner, but as hackers we don’t really care about warranties.

Beer brewing is as much of an art as it is a science. There are a lot of variables that go into the process, and tweaking any one of them can result in your beer tasting different. There is one process during brewing that is called mashing. Mashing is when you soak malted grains in hot water to pull out the sugar. The amount of sugar that gets extracted is very dependent on how long the grains are soaked, and the temperature of the water. If you want your beer to taste a certain way, then you want to ensure that the water stays at constant, repeatable temperature.

As a home brewer, [Ken] has been using his stove top to heat the water. This gets the water warm, but in order to keep the temperature consistent, he has to constantly monitor the temperature and adjust the knob accordingly. Who wants to sit around and do that all day? He needed something to control the temperature automatically. Enter the sous vide cooker.

Sous vide is a method of cooking in which food is placed into an airtight bag and then submerged in a water bath with very strict temperature control. The process takes a long time to cook the food, but the result is supposed to be meat that is cooked perfectly even while also retaining all of the moisture and juices. [Ken] figured he might be able to use a sous vide cooker to control the temperature of the mash instead of a water bath.

His experiment worked wonderfully. He used the stove top to help get the mash up to the close temperature, then the sous vide cooker was used to fine tune things from there. [Ken] says he was able to achieve 75% efficiency with his mash, which is exactly what he was going for. Continue reading “Brewing Beer with a Sous Vide Cooker”

Goldilocks Climate Box Keeps Lager Fermentation Environment Just Right

September was warmish in many places around the world including [Ole]’s native Denmark. But that did not stop him from brewing lager flavored with plums from his own garden, and neither did his indifference to lagers in general.

Lager fermentation requires a consistent, low temperature. While many homebrewers might modify an electric refrigerator, [Ole] wasn’t interested in the cost of running a second one just for brewing beer. Instead, he built a climate box to work with the cool temperature in his garage. Starting with scrap wood from other projects, he lined the walls with polystyrene and put a layer of wood on the floor to help support the fermentation bucket.

Maintaining a consistent temperature in the box called for both heating and cooling. He pulled the Peltier from a 12V cooler meant to run off a car’s cigarette lighter, and used a spare ceramic heater that was lying around in case his primary reptile warmer went on the fritz.

An Arduino and a custom shield drive separate PID controllers for the Peltier and the heater. The shield has a temperature probe, and he extended the USB outside the climate box so the PIDs can be adjusted without disturbing the inside temperature. The schematic, board file, and code are all available in a zip you can get from his post.

The Peltier couldn’t quite compensate for the overly warm weather and the heat caused by the fermentation, but it was stable enough to produce a nice, plum-flavored lager he has dubbed Lektor Blom­mes malt­bol­che, which is a triple Danish pun he explains in the write-up.

Margarita Drip Infuser Ensures a Perfect Mix

In order to get a margarita just right, the various ingredients need to be mixed together quite vigorously to over-come the different viscosity of the fluids. Looking to create his own barbot of sorts, [TVMiller] decided to make a Margarita Drip Infuser to help make margaritas a bit easier.

Using various chem lab supplies, [TVMiller] has cobbled together something pretty awesome. The Infuser can take up to 8 different ingredients into its test tube reserves, and after the drink ingredients are programmed on the computer, the magic begins.

An Arduino Uno controls a bank of 8 relays which control small fluid solenoids, with each control pulse releasing just a single droplet of fluid. An LED for each valve is run in parallel adding a bit of a light show to the mixing experience. If that’s not enough, he’s also created a copper cooling coil to chill the drink as it is poured.

Continue reading “Margarita Drip Infuser Ensures a Perfect Mix”

Keep an Eye on Your Fermenting Beer with BrewMonitor

The art of brewing beer is as old as civilization itself. Many people enjoy brewing their own beer at home. Numerous steps must be taken before you can take a swig, but fermentation is one of the most critical. [Martin Kennedy] took up the hobby with his friends, and wanted a convenient way to monitor the fermentation temperature remotely. He started working on the BrewMonitor, a cloud-based homebrewing controller powered by an Arduino clone.

His goal was to create something cheap, convenient, and easy to set up. Traditional fermentation monitoring equipment is very expensive. The typical open-source alternative will set you back 80 euros (roughly $101), using the Arduino-sensor with a Raspberry Pi gateway via the BrewPi webserver. [Martin] did not want to go through the hassle of viewing BrewPi remotely, since it requires a home network and all of the configuration that would entail. Instead, he coupled an Arduino clone with a DS18B20 temperature sensor while using an ESP8266 module for wireless communication, all for less than 18 euros ($23). This connects to a simple webpage based on with a PHP backend (Laravel with RESTful API), a MySQL database, and an AngularJS frontend to display the graph. Once the sensor is placed into the fermenter bucket’s thermowell, the temperature is transmitted once a minute to the REST API. You can see the temperature over time (in Celsius). The design files are available on GitHub.

[Martin] would like to expand the functionality of BrewMonitor, such as adding the ability to adjust the temperature remotely by controlling a heater or fridge, and lowering its cost by single boarding it. Since the information is stored on the cloud, upgrading the system is much easier than using a separate gateway device. He doesn’t rule out crowdfunding campaigns for the future. We would like to see this developed further, since different yeast species and beer styles require very stringent conditions, especially during the weeks-long fermentation process; a 5-degree Celsius difference can ruin an entire brew! Cloud-based temperature adjustment seems like the next big goal for BrewMonitor. DIY brewers salute you, [Martin]!

[via Dangerous Prototypes]


End Table Kegerator Hides the Tap when You’re Not Looking

What’s better than an ordinary end table? How about an end table that can serve you beer? [Sam] had this exact idea and used his skills to make it a reality. The first step of the build was to acquire an end table that was big enough to hold all of the components for a functional kegerator. This proved to be a bit tricky, but [Sam] got lucky and scored a proper end table from a garage sale for only $5.00.

Next, [Sam] used bathroom sealant to seal up all of the cracks in the end table. This step is important to keep the inside cold. Good insulation will keep the beer colder, while using less electricity. Next, a hole was cut into the top of the table for the draft tower.

The draft tower is mounted to a couple of drawer slides. This allows the tower to raise up and down, keeping it out of sight when you don’t want it. The tower raises and lowers using a simple pulley system. A thin, high strength rope is attached to the tower. The other end is attached to a spool and a small motor. The motor can wind or unwind the spool in order to raise and lower the tower.

The table houses an Arduino, which controls the motor via a homemade H bridge. The Arduino is hooked up to a temperature sensor and a small LCD screen. This way, the users can see how cold their beer will be before they drink it.

To actually keep the beer cold, [Sam] ripped apart a mini fridge. He moved the compressor and condenser coils to the new table. He had to bend the coils to fit, taking care not to kink them. Finally he threw in the small keg, co2 tank and regulator. The final product is a livingroom gem that provides beer on demand.

Demo video (which is going the wrong way) can be found after the break.

Continue reading “End Table Kegerator Hides the Tap when You’re Not Looking”

The Fridge Hacking Guide by BrewPi


The team behind BrewPi are at it again! This time they have created an online guide showing how to convert a min-fridge into a Raspberry Pi & Arduino controlled fermentation chamber. In it, they describe 3 possible options:

  • Option 1: Make a simple switched power cord, without hacking into the fridge electronics.
  • Option 2: Make a switched power cord, but also override or remove the thermostat.
  • Option 3: Rip out the thermostat and fully integrate the SSRs into your fridge (which is what [Koen] and [Elco] did).

First things first though. They had to clean the fridge. And depending on where they got it or how long it has been unplugged for, the inside might have been pretty rank and disgusting from mold growing out of every corner. This took a good hour or so to clean properly lest the brewing process get infected with external grossness. This is all worth it because a well-controlled fermentation chamber results in a superior batch of beer.

They put their laser cut case on top of the fridge, holding an LCD, Raspberry Pi, Arduino and the BrewPi Arduino shield. The Arduino reads the temperature sensors inside the fridge, the beer and the ambient temperature. Then it controls the SSRs they added to switch the compressor and a heater. Then, the cables were routed through the fridge and take control of the compressor.

Continue reading “The Fridge Hacking Guide by BrewPi”