Many moons ago, I used to brew my own beer. Nothing spectacular just a 25l fermentation bucket with a ready made kit. Since we moved house I’ve always had the plan of hiving off a section of the garage dedicated to beer making, the problem with that is my garage has literally been full of stuff. Now that most of the renovation projects are complete (nearly 5 years later) there’s room in the garage and I can now start brewing again.
I spent a lot of time reading about various fermentation methods, and one thing that jumped out at me was to ensure a stable temperature throughout. To achieve this a lot of people use a fermentation chamber, namely a fridge. I managed to pick up a really decent Bosch fridge second hand for £20. I also picked up a Hylite 1ft Eco Tube Heater (45W) and an Inkbird STC-1000 Dual Stage Digital Temperature Controller. By connecting the fridge and the heater to the STC-1000 and placing the included temperature probe in the fridge during fermentation allowed me to keep the temperature of the “chamber” constant.
A finished brew
The STC-1000 contains a microcontroller and 2 relays, one relay connects to the power cable of the fridge the other to the power cable of the heater. Once the device is powered you specify a desired temperature and a +/- allowed skew (in my case .5 of a degree C) place your fermenting bucket full of beer into the fridge and wait.
The fridge with the heater in
STC-100 with sockets ready to build
STC-1000 and sockets all neatly in a box
All this was brilliant and the resultant beer was pretty decent too, but in the back of my mind I was constantly thinking - hang on, a couple of relays, a microcontroller and a temperature probe, surely I can build this myself. Better still build it myself and get visible live and historical data. Now, I’d heard of BrewPi before, but they seem to have changed their tact away from using off the shelf components for a pre-built micro controller and I wanted to build this all myself, besides I’ve got a garage full of electronics kit ready for this kind of project and the use of both an arduino/microcontroller as well as a Raspberry Pi seemed a bit silly - I did read into the reasons why but it still made no sense to me.
Original gravity reading
Brew in fridge with both temp probes attached
Initially I put together a simple Wemos D1 with attached DS18b20 temperature probe and stuck it into the fridge alongside the other probe from the STC. This allowed me to test retrieving temperature data while leaving the STC to actually control the temperature during fermentation. I configured the ESP to fire out an MQTT message every few minutes or so with the temperature as the payload. I then retrieved this message and placed it into an Influx database, to be then visualised in Grafana. The results of this were pretty cool, not only could I have a graph of the temperature over the whole fermentation process, but I could also live view the temperature at that point in time.
All so far so good, but obviously we’re missing the next step and thats to control the heater and fridge with a couple of relays. This was but only a few blobs of solder away but I’ve also been planning on getting into all grain brewing, during my early research of this I found the excellent video of Christopher Aedo demonstrating his whole brewing process. In this he showed that he used a piece of software called CraftBeerPi, obviously this caught my attention. CraftBeerPi runs on the Raspberry Pi and allows the controlling of various devices such as relays and temperature probes from the and performs functions on them based upon a recipe of sorts. You can even upload predefined recipes.
Brew with yeast on top
I’m not at the stage where I’m ready to start all grain brewing, but I’m initially going to be building this to control the fermentation chamber in direct replacement of the STC-1000.
Thats pretty much where I’m up to with this project, but I will be documenting it here and possibly even creating some videos of me doing so.
One other element of brewing that I’ve been looking into is measuring the gravity and resultant alcohol content of said brew. The traditional way of doing this was to take a sample prior to fermentation measuring it with a hydrometer, taking another
sample after fermentation and again measuring it with a hydrometer. Once you have the 2 readings a calculation can be done to give the alcohol percentage, for example: Original Gravity = 1.039 Final Gravity = 1.010 (1.039-1.010)* 131.25 = 3.8%ABV
iSpindel in progress (2 devices)
Again, I wondered if there was a way to measure this using a sensor attached to a microcontroller. I then found the Tilt which looked pretty awesome, but a bit of trawling later I found the iSpindel project on GitHub. I’ve pretty much got my first prototype of the device ready to go, just a few finishing touches then I’ll be testing it. Another one for later posts I think.
All in all, I think I’ve made a decent start to getting brewing again, controlling some of the process with tech and having the data output visible.