Five Gallon Plastic Electric Brewery

by Ken Schwartz, KennyEddy@aol.com
From Homebrew Digest #1990, 3/19/96
I've been receiving a lot of direct E-mail concerning people's questions about the electric brewery approach, and I've been answering many of the same questions over and over, so I think it's a good time to post a summary of my brewery and give my two typing fingers a break. The inaugural "Pail Ale" is still in the keg carbonating but preliminary sampling has shown it's just fine -- no plastic taste or aroma; no signs of caramelization or scorching. The information herein describes how I built my brewery and my design may not apply to your needs or abilities. This posting is for informational purposes only and does not constitute encouragement or direction for you to build one. I make no claims about the safety or suitability of this brewery design other than that I haven't yet been killed by it and that the beer I've made with it came out well. Proceed at your own risk.

Vessel Construction

I used a five-gallon HDPE bucket for my HLT and a seven-gallon HDPE bucket for my boiler. I made sure the buckets were at least 0.090" (90 mils) thick by checking the thickness "rating" embossed on the bucket bottom -- I found that the cheapo 0.070" buckets allowed the element to sag when it got hot, but the 90 mil unit was just fine. For the HLT I installed a single 240V/4500W "bent" water heater element (State Industries #9000095) centered at 2" from the bucket bottom. I drilled a 1-1/4" hole using a hole saw. I placed the included gasket on the outside of the bucket and secured the element inside using a 1" copper "female adapter" fitting. A bit of teflon tape and maybe a nudge with vise-grips and I had a secure leak-proof installation. The boiler was similarly constructed but with two elements, one at 2" and the other at 4" from the bottom, mounted at 90 degrees to each other. For insulation I capped each element outside with a 1" PVC pipe cap which has a notch cut in it to pass the wires. It attaches with a few dabs of silicone adhesive for easy removal should I ever need to remove the elements. Gives it a nicer "finished" look too. I marked the outside of the buckets at gallon, half-gallon, and quart increments. You can see the water level from the outside, and you can see the markings from the inside, if the lighting is good.

I also installed in each vessel a 1/2" compression by 1/2" male pipe thread fitting. I drilled a 5/8" diameter hole near the bottom, and inserted the fitting compression-end first using a 5/8" "union washer" up against the hex flange on the fitting, (on the outside of the bucket). The tight fit ( I had to "cut threads" to install it) and the compression nut secure the fitting (I discarded the compression sleeve). I silver-soldered a copper-wire "mesh" (two wires in each direction) across the compression nut to act as a coarse filter. Before installing, I connected a 1/2" female pipe inlet by 3/8" compression outlet, CPVC "angle stop valve" to the fitting (for a tight fit) using teflon tape. The 3/8" compression outlet on the valve allows me to attach various lengths of water supply feed tubing to accomplish the various liquid transfer functions. I suppose I could've used metal valves but the plastic tolerates the heat, has low turning torque, and opens or closed in a half-turn.

Vessel Wiring

I run my brewery off 240V. The HLT is wired directly to a plug and the element thus generates the full rated 4500W. Five gallons of strike or sparge water heats from room temp in about 15 minutes or so. I tried using a water-heater thermostat but there wasn't enough thermal coupling to make this work well. I also found that the water underneath the element stays cooler than the water above; there's not enough convection without boiling to mix it up. So I have to stir it well before taking the temperature to determine readiness for striking/sparging.

I wired the two boiler elements in *series* to give me 2250W total, 1125W for each element. This ensures scorch-free operation. The 2250W level heats sparged wort to a boil in 30-40 minutes, but the wort will boil over at this setting. I use a diode (25A / 400 PIV) in series with the boiler wiring to cut the power in half. The diode has a switch across it to allow full power to be applied during heat-up; I drop it to half-power when boiling is acheived by opening the switch. The diode is a bridge-rectifier module; I couldn't find a single diode with sufficient rating. I got mine locally at a pars-replacement house; part number ECG5324, about $6.

I strain-relieved the power cords to remove mechanical stress from the element terminals. Otherwise, I would risk breaking the wires off at the element from constant flexing, thereby creating a shock and/or fire hazard. What I did was to bolt a cable clamp placed around the cord to the bucket. I used a #10 brass bolt and nut with a "sealing washer" on the outside of the bucket between the clamp and the bucket wall (it has a metal washer bonded to the rubber; I placed the metal side against the cable clamp and tightened securely).

Stand

I built a two-tier stand (the floor is the third level) on casters from 2x4's and plywood. I sized the stand so that liquid transfer from one vessel to the next is all gravity; no siphoning. It doubles as storage when not in use. All my control switches are in outlet boxes mounted to the 2x4 frame, with switch and outlet covers enclosing them. I used a red switch cover plate for my main power switch to make it readily visible.

Brewing Process

Before I brewed beer I "brewed water" to check for leaks and other potential problems, and to observe the process. This is where I first noted the too-vigorous boil at 2250W and decided a half-power setting would be necessary. Good thing, because 2250W DOES boil over. I also accidentally fired up the HLT with no water in it. The element became red hot and burned badly in *seconds!* I know now that it MUST be operated only when fully covered with water!

I strike into my mash tun (single-step infusion; Coleman Drinking Water 5) through metal supply tubing designed for the valve I chose. It take about four minutes to strike 3-4 gallons but I am able to hit my target temperature with great precision. I made sure I did a "practice run" first to determine the temperature drop I was to expect. I decided not to just dump the HLT into the mash tun because the buckets get hot and flexible, and I didn't want to make a dangerous mess.

I sparge in a similar manner (using supply tubing), using the valve on the mash tun (same kind) to slow the sparge rate to about 5 minutes per gallon. The boiler is on the floor during this time; after sparging is complete, but before I plug it in to boil, I lift the bucket to the mash tun level so I can get at it easier, and, later, so that I can gravity-feed into the fermenter.

At 1125W I lose about 1/2 gal to evaporation per hour. When I "brewed water", I lost 1 gal per hour at 2250W.

The CPVC supply tube from the boiler to the fermenter has three holes drilled at a downhill angle near the spigot end, to act as an aerator for the chilled wort. I got 5 gallons of wort with 1-1/2 gal foam on top in my 6-1/2 gal carboy -- it just fit

Immersion Chiller

I built an immersion chiller into the boiler bucket lid. I used about 10 turns of 3/8" copper tubing wrapped around a paint can. It hangs from the lid thanks to two elbow fittings installed on the top side of the lid, which bring the tubing over the edge of the bucket. The cold water enters at the top of the coil, which will hang just below the wort surface, extending down to about the 2-gallon level. I place the chiller lid on the bucket and into the wort, guarding the cooling wort from debris and allowing me to gently "swing" the chiller through the wort for efficient cooling. The chiller has a garden-hose fitting on the inlet side. I also use a pre-chiller coil immersed in an ice bath after the wort drops to ~120F. A small hole in the lid allows air to enter as the air in the bucket contracts, and is also handy for inserting a long-probe thermometer for monitoring cooling. I also stuck an aquarium thermometer on the outside for an alternate way to read the temeprature (once close to pitching temp).

Plans for 120V Wiring

At some point I may make a 120V version which might give me more flexibility in locating the brewery or even allow me to bring it to a friend's house or whatever. It will use the same 240V/4500W elements that I am already using. I'd need another element in the HLT; otherwise it'll take too long for the water to heat (it's gonna take longer as it is due to the reduced power). I'll wire the two elements in parallel, but I'll need to play games with the diode approach since the two elements in parallel will be very close to 20A and I'll probably get lots of nuisance trips of the circuit breaker. If I wire a diode in series with one element, I can limit the average current to around 15A (power = 1125W + 563W = 1688W), while still obtaining reasonable heating times. Whether I would need to switch down to 1125W by disconnecting the diode and element, to avoid boilover, remains to be seen. I would be damn sure that the house-wiring circuit I use is (1) GFI protected and (2) 20 amp rated (breaker *and* wire). I'd estimate evaproation loss at 3 quarts per hour at 1688W (if it doesn't boil over).

Cleaning

Two things I noticed -- the hops colored the white boiler green, and the acidity of the wort blackened the element wire. The black on the element did not come off; I suspect it's an oxide layer and I'm not gonna worry about it. The hop stain came out pretty well when I boiled plain water for 15 minutes after hosing out the boiler real well (especially inside the "female adapters"...no lewd puns intended).
That should give you a very detailed look at my brewery design. It allowed me to get out of the kitchen (I brew in the garage now), to do full-volume all-grain without hassling with a propane setup and the associated fire and CO risks (although obviously there's a risk trade-off with the electricity), to keep my batch size to a convenient five gallons, and to eliminate siphoning from the wort production phase (I still use a glass carboy for fermenting so siphoning is not totally gone).

Ken Schwartz
KennyEddy@aol.com