Brewduino

I put down my first all-grain batch of beer the other day, and discovered that the arduino-based thermostat I had made for it had stopped working. I put the beer inside to keep warm, and it seems to be ok, but it prompted me to continue work on my brewing computer.

I now have a functioning network, so I've decided to add a reporting feature to my device. I've written the first revision of the code, but haven't yet got all the hardware going.

Here are the functions planned:

Internet enabled
Temperature sensing
Thermostatic control (hopefully with PID/PD)
Specific gravity sensor
Temperature calibration for gravity readings (reads gravity and spits out what the value would be if the liquid were at a set temperature)
Alcohol content calculation
Daily report of gravity, alc% and temperature via Twitter and email
Thermostatic control failure alert via Twitter and email
'Time to bottle' alert via Twitter and email
Datalogging

I'm yet to get the gravity sensor working, but that shouldn't be too much of an issue. I also haven't trialled the datalogging to SD card or PID yet. So far I know I can get it to send me an email with the readings, and I know it can control the temperature. More to come when I'm closer to completion.

Success!

So, having finished making my immersion heater and insulating jackets, I found the time to put down a new brew. It's an ale with honey making up the bulk of the extra sugars.

Anyway, I hooked the immersion heater up to my arduino thermostat, with the vat snug in its wet suit, and off it went. I did, however, however, have a slight hiccough with the thermostat. Before plugging it in and leaving it, I decided to do a double-check that everything was working fine. It wasn't. Long story short, my power supply wasn't stable enough to form a stable reference voltage, so the temperature reading varied by +/- ~15 degrees C. Ridiculous... Anyway, I plugged the arduino into my laptop, plugged the charger in, and left the whole lot looking after the beer.

6 days later, it was bottling time.

Pictures ahoy.

The two lovely wet suits, dutifully awaiting the literal and proverbial 'chop', alongside their soon-to-be best friends, the 5 litre jar complete with cider on the left, and the 30 litre vat on the right.

One leg removed to make the sleeve for the jar.

Completed sleeve, I tucked a bit of scrap in to complete the sleeve.

And here's the vat in it's wet suit. Right on the front you can see a line of rough stitches, there's another one just on the edge on the right, these join a panel in to make the sleeve big enough to cover the vat. I also cut out a little slot for the tap.

I would show you the immersion heater, but I haven't got any photos of it, and it's pretty dull anyway. I just bought a length of aluminium tubing that was slightly too small to go over the end of the cartridge heater, then drilled one end out to 8mm, the diameter of the heater, and araldited the heater in. The tube is about 300mm long, and has a terminated mains cable coming out the other end ready to plug into the power outlet from my thermostat.

Immersion heater plans and ideas

After struggling for a long time to find an immersion heating solution that was

a) affordable

b) relatively small

and

c) easy to immerse without contaminating the brew

I gave up and built a light box for my vat to sit on. This works well enough, but takes up space and has a light bulb in it, which is prone to breaking.

The other day, I was working on a vacuum box and needed to make a hole behind the electronics panel airtight. I did the obvious thing and filled the hole with hot glue. The problem being that my hot glue gun has a broken trigger mechanism, meaning that I have to manually push the glue sticks through. In the process of trying to quickly fill the hole up, I pushed ab it too hard, and shot the heating mechanism out the front end of the gun.

So no I'm down one glue gun. On the plus side, I got a small heating element that runs directly from mains power. Untouched, it measured about 10cm by about 2.5cm in height, and consisted of a stainless steel tube with the familiar conical nozzle at one end, with a stainless steel block mounted underneath, from which a pair of wires protruded. Guessing, based on the thickness of the walls on the stainless steel tube, that the heating element itself was confined to the block under the tube, I promptly cut the tube off to make the whole thing smaller. My guess was correct, so I now have a stainless steel heating element about 15mm diameter, 50mm long.

My next step will be to mount it in a brass or copper tube filled with mineral oil, this will allow me to mount it firmly throught the top of the vat, preventing it from touching the sides. It will also prevent the brew from conducting the 240 volts that are running to the element. There are two reasons for putting the mineral oil in there. Firstly, it is non-conductive, so the wires will be safe in there. Secondly, is removes air from the vessel, which is a poor conductor of heat, the oil will transfer the heat from the element to the brew more efficiently.

At the end, I hope to have a completely sealed unit about 200mm in length that I can easily mount, and easily swap between brewing vessels.

I'll post pictures and further information as I go.

Homebrew experiments.

As my previous post may imply, I've been playing around with homebrewing beer and with controlling the various processes involved in this. From now on, I plan to post my various prototypes, ideas, plans, and findings here. At the moment my list of things to integrate into my system includes:

-Improved thermostatic control, possibly using a PID system

-Immersion heater for direct heating of the brew, this also saves space

-Electronic hydrometer to tell me the specific gravity of the brew, the alcohol content, and when it is time to bottle

-A convenient, inexpensive, and space efficient method of thermally insulating the brewing vat.

I guess while I'm at it I'll also post the results and recipes of my more experimental brewing attempts.