It sure ain't pretty!
Here's an overall
photo and a photo of it's innards:
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It sure ain't pretty! |
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I started brewing on top of the kitchen stove but had to switch to outdoor brewing after a very nasty boilover soaked the insulation inside the stove. I hated lugging propane cylinders to have them refilled and wanted to brew indoors in a safe manner (more electrical advantages are below). I then built my first electrically "fired" plastic pail boiler after studying Ken Schwartz's excellent web page. Basically, it was two 120 VAC heating elements inserted thru holes in the side of a plastic pail. It was fine as a first stab, but was a bit slow to reach boiling, so built the boiler shown on this page. The primary downside to it is that a 240 VAC, 20 Amp. circuit is required. I installed a new circuit, but an electric dryer receptacle could be an alternative. What's great is speed it reaches boiling (6.5 gals. in 18 minutes) and it's big enough for 10 gal. batches.
Cutting the Hole for the Lid: This seems to be a concern for many folks. I found it much easier than I'd anticipated after reading many HB Digest posts on the subject. After scribing then marking the cut line for the ~12" hole and drilling a starter hole, the lid opening was cut using a variable speed saber saw with a rotatable blade holder and it's base removed and 32 tpi HSS blades. It took 3 or 4 blades- I broke a couple until I got the hang of cutting on the curved keg top. The cut was very good and required only a little touch-up and chambering work with a file and then some sandpaper. Renting a "Sawsall" is an alternative.
Insulation: The carpet padding works well and is much cheaper than foam sleeping bag pads or the aluminum faced bubble wrap used on the old boiler. The relative disadvantage is that it'll adsorb spills. I used about three layers of 1/2" padding around the sides of the keg and as much as I could stuff under the bottom (layers close to the keg were cut like into donut shapes). One day I'll get around to encasing the exterior insulation an outer layer of aluminum faced bubble wrap to reduce the likelihood of spills getting to the foam.
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Due to the high current at 240 VAC being controlled, this is definitely NOT a good first electrical project! |
Here's the schematic and wiring arrangement:
The design isn't mine- except for a few part value changes, it's based entirely on Ron La Borde's controller. THANKS Ron! His web page has lots of very good info.
The controller uses PMW to control the amount of power to the heater. Basically, twiddling with the potentiometer. varies the power to the heating element by shutting off power for variable periods of time over about a fixed 1.5 second cycle period- this is also known as varying the duty cycle. The pot. varies the duty cycle of 1/2 of the LM556 which is set up as a free running oscillator. When the output from the LM556 is high, the solid state relay (SSR) is conducts thereby completing the 240 VAC circuit and powering the heater. .It affords much finer control that the old kitchen range controller I used to use with a much lower wattage 120 VAC heater element.
The box with the pot for controlling the heat has 2 LEDs- a green one that indicates there's 12 VDC power to the circuit and a red LED that lights when the controller is telling the SSR to turn on. The later gives a visual indication of the amount of power that's being feed to the boiler- i.e., the longer the red LED is on during the 1.5 second cycle period, the more the power being supplied to the heating element.
It goes from about 10% to 100% power, so an "off" (note the quotes!) switch is included on the box with the pot. It doesn't actually / effectively disconnect the 240 VAC power tho' so there's a double pole "MAIN" power switch in the 240 VAC power upstream of the receptacle. DO NOT WORK ON HEATER OR CIRCUIT WITHOUT TURNING THE MAIN, 240 VAC POWER SWITCH OFF! I always pull the plug to further ensure safety.
One may be thinking at this point that the attachment plug can be used as a disconnect and the switch ommitted. That's technically true, but I don't recommend it. Although pretty rare, SSR's can fail "on" due to a failure of the controller that's driving their low voltage side, voltage surges on the 240 VAC supply or inadequate cooling. If it fails "on", a switch is much safer and handier than pulling the attachment plug.
A double pole switch must be used for the main switch- a single pole switch in one leg of the 240 VAC supply (like a 120 VAC circuit) will only kill one of the two "hot" 240 VAC legs. The one I use looks like a regular light switch and may require some shopping around to find. Make sure it's rated for at least 240 VAC at 20 A.
The grounding conductors are not shown in the drawing above but they are MANDATORY! All of the exposed metal parts of enclosures with 240 VAC in them are grounded as is the keg itself- the later via a ring terminal and a SS sheet metal screw/lock washer in the lower rim of the keg close to the heater element. The lower rim of my keg was very tough to drill- I finally had to use resort to a carbide drill bit. I suspect this may be a feature of the keg to make the rim tough and able to withstand dropping when full, but it may have been due to my heating the keg over a propane burner when initially cleaning it.
3 conductor, 10 AWG type SO flexible cord was used for all of the 240 VAC wiring. Although lighter duty SJO cord could be used instead. I recommend spending the few extra bucks for type SO cord. With 20A, one wants really good connections so I recommend crimp type terminals whereever possible. I made an exception to this rule for connecting to the attachement plug.
There's no GFCI shown but one could be included. GFCIs rated for the use are expensive ( > $100). I consider the electrocution risk vs. cost a decent trade-off; however, YMMV! BTW: One handy trick I learned long ago when I had to go in a lot of factories and such was to slap exposed metal parts of equipment that could be energized with the back of my hand before otherwise touching the equipment. It's a good habit to pick up...
A clean/well filtered 12 VDC power supply must be used for powering the controller- otherwise the LM556 (or LM555) may false trigger on the ripple from an inadequately filtered power supply. If the controller acts flaky with the supply you use, adding a large value capacitor (something like 100 to 1000 uF rated at least 20V) across it's output leads will help.
Don't use a marginally rated heat sink. The 4,500 watt heater draws 18.75 A. A SSR rated for 20 Amps. is not adequate IMHO. For triacs and SCRs, a 75% derating usually recommended. I selected a 40 A SSR but a 25 A rated SSR should work. Needless to say, it must be rated at least 240 VAC.
The SSR MUST have an adequate heat sink. In mine, the aluminum enclosure which houses the receptacle and SSR also serves as the heat sink for the SSR. To ensure this, I used a beefy load spreader/sorta heat heat on the opposite side of the enclosure from the heat sink, heat sink compound between the SRR/enclosure/spreader, and tighten the two fastening screws/nuts/lock washers well. For the load spreader, I used a piece of beefy aluminum angle (shown in top right of photo above). It also has a hole drilled in it's projecting leg for hanging it up. To ensure the heat sinking is adequate, do a test boil at full power and check the temperature of the enclosure and load spreader (remember the "slap it first" tip above....). If either are more than warm to the touch, use a "real" and beefy heat sink instead of just the enclosure. UPDATE: The foregoing worked for me except during a summer canning session when it was almost 100 degF in the garage. The enclosure never got hot, but was too warm for my taste so I substituded a real heat sink for the aluminum angle.
A handy upgrade: Omit the 12 VDC supply switch and use instead a potiometer with built-in switch (www.digikey.com- #CT2233-ND, ~$3.48)
A hole was cut in the keg just above the chime weld and 45 degrees off axis of the ports so the inboard plumbing attached via the ports would not interfere with the element. The element was secured in the hole in the keg with a gasket and a 1" stainless steel half-coupling screwed onto the inboard end of the threaded heater base. (from http://PlumbingSupply.Com/stainles.html#couplings ). The half-coupling is cheaper ($3.54) and, being SS, should cause less corrosion of the heater based than the copper "nuts" I used on the old boiler. A thick gasket was selected so it can conform to the curved keg wall without an excessive amount of half-coupling tightening torque. An alternative is to add a gasket cut from gasket sheeting. The electrical terminals on the outboard end of the element are covered with a PVC 1" female slip x 1/2" female threaded elbow (http://PlumbingSupply.Com/pvc.html#90). 6 or 8 slots were cut in the 1" end and it was fastened to the plastic part of the heater with a hose clamp. A clamp type electrical fitting was screwed into the 1/2" threaded end to provide strain relief for the power cord.
The Sight Gauge
Here's
a page that describes how it was made and how it's used. An alternative
is to ditch the separate port for this and tee off of the wort in/out port
to a sight gauge. Alas, one then looses an easy way of monitoring
the progress of filling and draining the boiler of wort since the flow
of wort induces a pressure drop which causes the sight gauge to read too
low. A work-around is to stop the flow to take a level reading. An
update: I initially sawed slots in the inboard end of the 1/4"
SS pickup tube but they were subject to plugging, so, a piece of SS mesh
was put over the end.
Temperature
Probe
This was made in the same manner as as
the port for the sight gauge above. The temperature probe
is just a short length of 1/4" SS tubing with a thermistor embedded in
in it's end with silicone sealant. Details on the probe and how to
make one is on the Thermistors for Brewery
Temperature Measurement page.
Currently, I connect the cable from the thermistor to a volt-ohm meter, read the resistance of the thermistor then refer to a table of resistance vs. temperature values to determine the temperature of the wort. This will be via computer one of these days. I use it only during the ramp to boil (to tell when to start watching for a boilover) and during chilling after the boil. It serves no purpose during the boil since it always reflects the 212 degF of the boiling wort.
Something which might be worth making is an alarm gizmo which sounds an audible alarm when the boil approaches. Something like the simple fridge controller set for 212 degF or maybe a bit under that.
Wort
In/Out Port
The wort in/out port is via a 1/4" FPT
tapped hole. This size allows 3/8" OD tubing to pass thru via a suitable
fitting after the fitting is drilled out to 3./8+". I
wouldn't try tapping the keg any larger than 1/4" FPT- the decreased thread
engagement would make the port too weak IMHO. The 1/4" FPT affords
enough strength to withstand the typical knocks and bumps of brewing but
I doubt it'd take gross abuse. The tee at the inboard end is
soldered to the copper pickup tube and the other end of the tube was swaged
so it fits over the 3/8" SS tube in the port. A short length of heavy
wall vinyl tubing is secured with two hose clamps over the joint to make
it air-tight. This is required since the wort is siphoned out when
the level of wort is lower than the port. The vinyl discolors after
the first brew but doesn't seem to throw off anything that taints the brew.
Hi-temp. flex tubing may work better. One day, I'll try a bent length
of SS tubing for the tee and thru the port....
Manifold
A 5' length of tubular SS mesh removed
from the exterior of reinforced plumbing connector serves at the strainer
for the hops and most of the trub. It was formed into a rough and
loose coil of 3 loops and each end of the tubular mesh was secured over
the two ends of the tee at the end of the pickup tube by wrapping
SS wire. It works very well- especially if one waits for 5 minutes
or so for the hops to settle and form a good filter bed. I have recently
tried it with pellets for the boiling hops and whole hops (at least an
ounce) for late additions. Works fine as long as one doesn't run-off
too fast. The rate varies with the brew and, especially, the amounts
and types of hops and when they are added. It takes me in the vicinity
of 20 minutes for a 5 gal. batch. I start real slow and gradually
increase the flow until it first starts to slow then back off a bit- it
takes a bit of experience. For clearing a stuck run-off while learning,
I use a blast of 30-40 psig CO2 via the end of the wort-out hose although
I'd rather use O2 if I had a real cylinder instead of one from a Bernzomatic
torch.
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The white stuff along side the shaft of the stirrer blade isn't solder- it's beer stone from about 20 brews and just using blasting with water for cleaning. |
A stirrer is NOT needed to prevent scorching, but, when used during the boil, it does appreciably increase hop utilization. Where it's of immense benefit is when cooling the wort- it GREATLY shortens the amount of time required since the wort is being moved over the surfaces of the immersion chiller.
The boiler drawing and photos above shows most of the details. The stirrer is basically constructed like the one used on the old plastic pail boiler. The only significant delta is that the blade has a higher aspect ratio to accommodate the lessor wort depth and the wider top opening. It was made from a 9" long piece of, I think, 3/4" copper tubing. Like the old one, the copper tubing was slit, pounded flat then bent into a S shape.
The stirrer is powered by a small, cheap
12 VDC, 200 mA gear motor which "floats" atop the shaft- i.e. it's fastened
only to the shaft via a crude, homemade coupling. It's body is restrained
from rotating by a rod which engages a hole in the wood cross piece.
This accommodates the wobble due to the crude coupling. It's speed
is controlled via a variable voltage power supply. Here's a photo:
Affixing the bolts that secure the wooden stirrer cross bar to the keg took me quite a while to "brain-fart". Having the bolts welded on sure would have been less pain! I designed the lid to be reasonably tight when closed to keep nasties out of the wort while it's being cooled and racked off. My plan was putting some sort of thin flexible plastic material under the leaves of the piano hinge before it was screwed and pop riveted in place to afford better sealing but I couldn't find anything suitable.
There are two notches in the lid to allow the vertical feeds of the immersion chiller to pass through. The chiller is placed in the boiler 5 minutes or so before the end of the boil to sanitize it. I tried using duct seal to seal the openings in the lid around the chiller feeds but it's really messy and a PITA to boot. There's also a ~3/4" hole in the wood (poplar) cross bar that I planned/brain-farted stuffing a silicone stopper into to allow filtered air into the boiler as the wort is being cooled (i.e., to allow for shrinkage). After 30+ brews clean , I don't worry about infections from the air gaps.
When the tap water is too warm to get the wort to yeast pitching temp, I cool with tap water until the wort is within ~10 degF of the tap water temp then switch to recirculation of ice water thru the chiller. I do this by filling the HLT with ice and water and then using it's pump to recirculate the ice water. It works very well and requires no additional equipment. A marine bilge pump in a picnic cooler will work also.
The manifold is good, but using only pellet hops will plug it. Even whole hops that have been boiled more than a couple or three minutes will tend to plug it but not as bad. In either case, adding whole hops when the power is killed works. They seem to form a better filter bed. At least an ounce is required to form a decent filter bed, but more is better. Allow them to settle for at least 5 minutes after cooling and killing the stirrer.
For sanitizing the wort outlet and sight gauge vinyl tubing, I run boiling wort thru them shortly before the end of the boil. I do this by sticking the free end of the tuning into a 2 or 4 cup Pyrex measuring cup and then lower the cup to allow the boiling wort to flow thru the tubing. When the cup is about full, it is raised which allows the wort to siphon back into the boiler. This is repeated several times. A bit of plastic wrap is put on the end of the wort-out tubing to keep it sanitary. The sight gauge tubing will suck in air was the wort is run off from the boiler, bit, I don't worry about it. If this worries you try a silicone stopper over the free end or maybe a HEPA filter like those used for wort aeration.
Don't run off too fast or the filter bed will plug. I get about 1/2 GPM with 2 oz. of whole hops added at the end of the boil. If it does plug, blow CO2 thru the wort-out tubing and kick in the stirrer. Allow the filter bed to reform for 5 minutes or so before restarting the run-off. The clamp type valve used on the wort-out tubing functions as both as a shutoff and gross throttling control. A screw clamp lab type pinch gizmo is used for fine throttling.
I've never cleaned the thing with anything but plain water and a bit of wiping with a sponge. After 30+ brews, there's some tough residue where the wort level is during boil, but no crud elsewhere. Curiously, the only beer stone visiable is onthe stirrer. Wort has never scorched on the element, but after cleaning and drying the element has what looks like a very thin mineral deposit on it- it's shown on the photo above. I don't worry about this since it disappears when even slightly wetted. The only places where what may be beerstone is noticeable is on the blade of the stirrer adjacent to the shaft- it's shown in the photo above of the stirrer.
If you use the stirrer during the boil, be consistent using it batch-to-batch since it increases hop utilization significantly!
A computer based controller is planned (and has been for years....) Planned features: elimination of boilovers via automatically stirring the killing the heat and stirring the initial foam back into the wort then sounding and alarm (so I can watch for a boilover) and restoring heat. Automatical adjustment of the boiling rate to yield the target volume of wort in a given time, display and logging of temperatures (wort and water input and output on the immersion chiller) as well as wort level via a level transducer would be nice also.
At the very least, a gizmo that sounds an alarm just before boiling is reached would be nice. It would warn you to keep an eye peeled for a boilover and to throttle the heat back. Something based on the simple fridge controller should well. Even with a 5 gal. batch in the 15.5 gal. keg, I've had one boilover from not paying attention. BTW, to greatly reduce the chance of boilovers after the initial foaming, kill the power to the heater when a good boil and 1-2" of foam is attained and stir the foam back into the wort akin to that one uses when folding beaten egg whites to make a souffle (ask your wife or mother :-).
Subcoooling the wort aids in cold break formation and entrapment in the hops filter bed. I've done this a couple of times once to ~50 degF using ice water recirculated with the HLT pump- even got condensation on the outside exposed portion of the boiler! I guessed it reduced the amount of trub in the primary fermenter by about 1/3. Some or most of the reduction may have been due to the increased settling time tho'. The big downside is having to wait until the wort warms in the fermenter to pitching temp although I suspose one could recirc. hot water thru the chiller to warm the .wort up after subcooling. Too much of a hassle for my taste....
1. To me, electricity is much safer
than propane. The worst case accidents with electricity are me electrocuting
myself or causing a fire if I screw up royally and do something really
dumb. With propane, BIG explosions and fast spreading fires which
could endanger my family are the primary risks. YMMV....
2. Automating the boil by cutting
back the heat when boiling is attained (or excessive foaming is detected...)
and killing the power at the end of the boil will be fairly straight-forward
if/when I get around to it. Doing that safely with a propane burner
is expensive and, more importantly, is fraught with many hazards and problems-
some of which are not intuitively obvious.
3. The boiler can be insulated much
easier and cheaper compared to a propane fired one..
4. The cost of building an electric
boiler is more than using propane, but the operating cost is much less
It costs only about 30 cents to boil a 5 gallon batch in these parts.
Areas with non-public/corporate (and hence greed) power suppliers companies
(and especially in "deregulated" areas will be costly due to our
systems preversion of Adam Smith's "invisible hand" transferring
your
wealth to greedy corporate execs., inside traders, "Wall Street", corrupt
politicians and regulators... ad nausem. With propane
currently being $13 for a 20# cylinder refill, it'd be at least a buck
a brew just for the propane and more when you add the truck mileage to
take the cylinders to have them refilled.
BTW, one shouldn't haul a propane cylinder in a car or van. I do make an exception for Hummers owners tho'. A tip for them which will increase the cylinder pressure and hence ensure a boil as "macho" as their vehicle: On a hot and sunny day, have an old style propane cylinder filled to the max. by telling the filler to ignore the scale he'll want to use- fill 'til the pump starts to make funny noises, drive home, park in sunny spot, leave cylinder in Bummer with windows up and wait awhile (ommission of exiting vehicle is intentional). Oh yes, if one wishes to stop at a store on the way home from cylinder filling, please do not park as most Bummer's do- e.g. in fire lanes, in traffic lanes or take up two or four parking spaces close to the store.
Downsides
to Electric Wort Boiling
1. Electricity can kill you, although
I consider it less risky than propane as per 1 above.
2. Making a electric boiler requires
electrical knowledge/experience/skill!
3. Will very likely cost more than
a propane fired boiler.
4. Some sort of controller or other
method to throttle the heat back after boiling is reached is required.
5. For the rig on this page, a 240
VAC at 20 A supply is required.
If 4 and 5 (and maybe 3) above are impediments, consider something like my old plastic pail boiler instead of a keg.
Ron La Borde was of great help with the new boiler. His boiler page, helpful email and especially his boiler controller (upon which the LM556 application in the schematic above was stolen!) saved me a ton of time and worry about if what I was designing (more like brain-farting) would work.
THANKS guys!
Revisions
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