I know that this is possibly a bit arse-about-face, but I’ve been playing with Google Sketchup to create a set of plans for my hopper design. Not so I can build it, but so you can!
Stay tuned for more…
So you’ve bought yourself some awesomely cheap electronic scales from ebay. But what about when someone pours a beer on them, they run out of batteries or just stop working?
The answer: you only find out when you desperately need them! And usually this is when you already have your sparge done and you’re on the boil. Or worse still when you’re halfway through your hop additions!
My quick and dirty solution? A jerry-rigged balance scale made out of a steel ruler, a pencil, two egg cups and a cough medicine measure…
Place the ruler on the pencil and an egg cup on either end. Move the pencil until they balance. Measure the weight of hops you want with the medicine measure (in my case 7mL = 7g). Pour it in one egg cup. Carefully add hop pellets one at a time to the other until the water cup rises. Bingo 7g worth of hops! (well, as close as we’re ever going to get at short notice)
It’s cold and wintery and there’s something about brewing yeast that is clearly some kind of cosmic prank: all the beers you drink in summer need to be brewed at cold temperatures (lagers) and all the hearty ales that you might drink in winter like a warm temp!
I thought it time to complete the fermentation fridge by giving it the ability to heat as well as cool (after struggling to brew a hefeweizen under an electric blanket in the kitchen!). My STC-1000 aquarium thermostat already has a heating and cooling side wired up so really all that is required is to put in some kind of heating element. I originally had a 28W lightbulb doing the job, but I didn’t really like the fact that I could burn my fridge down (I had a close call with an ominous brown discolouration of the liner) and the UV put out by the lamp is not exactly great for beer (it comes in brown bottles for a reason!) . So time for a proper heater…
There are two main styles available: a belt and a pad. Belts are cheaper and more efficient at heating your brew as they wrap around the side of the fermenter and conduct directly into the beer. But I brew inside a well-insulated fridge and rely on a thermostat taking readings of the air inside the fridge. Heat the brew and it’s going to overshoot wildly while the air inside the fridge catches up – I don’t want to use my beer as a makeshift radiator!
I went with a heat pad. It sits nicely in the bottom of the fridge a shelf or two below the beer so it’s heating the air and not the beer directly.
It’s only a 25W model. I figured that it was pretty much the same as the light bulb I’d been using. After watching it only increase temperatures incredibly slowly over a number of hours I began to get worried. But no need to – I had 40L of beer in the fridge and it takes a while for things to reach equilibrium. So if you’re wondering: a 25W pad is perfectly capable! In fact its low “seeping” power means that it doesn’t rapidly heat, trip the thermostat, overrun, plunge and then repeat over and over.
Due to the coarse nature of the dial control on my HLT (which was originally a boiling urn for a conference room), I have had to hover around the tank with a glass thermometer held in the top waiting for the right strike/sparge temperature. Miss it and it’s another wait with the lid open.
Clearly this instrument was never designed to be particularly accurate and there’s a ridiculous impediment to watching it – often perched on a milk crate to get up there. What I really need is a large, easy to read display that is always reporting the temperature and ideally some electrical control to get me the right temps.
Solution is another STC-1000 aquarium thermostat, just like I used in the fermentation fridge. I fitted the HLT with a thermowell to accept the NTC probe using the same silicone muffin tray gasket technique I used on the keggle. Then I set it up for a trial run with a second digital thermometer dangled in the top to see how accurately it would heat to temp (although in the picture it looks like 7 and 17C, it’s actually my camera catching the scan-rate of the LED displays!). All went well, it would heat to temp and then overshoot by 2C – not a problem, factor that into the process and write it on the side of the HLT 🙂
With the proof of concept passed, it was time to commit it permanently to the HLT. I cut the end of the NTC probe off and connected it to a gold, insulated RCA socket mounted in a 15mm brass pipe plug. I then filled the plug with epoxy so that I would then be able to pump the thermowell full of thermally conductive grease without any risk of it being electrically conductive. Seeing as NTC uses resistance to measure temperature I figured that even a small level of conductivity of the thermal compound would throw my temps off – and, lets face it, it was cheap and easy to do and made all my connections far more hard-wearing.
Lastly I soldered an RCA plug to the thermostat end of my cut wire and bingo: digitally controlled, set-and-forget HLT!