This is a crosspost stolen from my original thread over at Canadian Homebrewers. I thought some of you might like to see what I have created!
I love this rig. It was a HERMS, but I wasn't overly happy with the lag with that system, and I really enjoyed some of the steam posts I've seen here on HBT, so I figured I would have a go. Disclaimer, as always... make sure you know what you're doing before you mess with steam. I'm a physical chemist, so I know the risks and energy steam can deliver...
What I've done is take a brand new 40lb propane tank - new to avoid any issues with propane explosions and the mercaptan sulfur smell associated with it - and convert it into a steam boiler. A 1" pipe flange was welded into the bottom, and a 6000W 240V element placed into the tank. The valves at the top allow me to take steam out and use it as I see fit, as well as refill the boiler. Propane tanks are rated for well over 300psi based on my research, so I feel very safe using this as a pressure vessel. Also fitted on the top is a 100psi safety pop off valve and a pressure gauge. The pop off is directed to the back, away from anyone - so there is no direct scalding risk.
From the boiler, I ran a hard 1/4" copper line to my mashtun. Inside the MT is a copper manifold with a dozen or so 1/16" holes for direct steam injection below the false bottom.
Now, to control steam input, I could use a ball valve... OR I could do this:
What you see is steam input is controlled via a 120V solenoid... For testing purposes I just used one of my pump switches to turn it on and off. Next step is to connect it to my MT PID controller (you can see the PT100 temp sensor on the recirculation outlet) for precise temp control. The beauty of steam heat is that it is a gentle heat, with zero risk of scorching anything, and when you turn the steam off, heating halts immediately. There is very little lag other than about 3-4 seconds of bubbles (generally condensed steam in the line) when the steam is turned on. Once you have active steam coming out of the manifold, you can barely see it, other than a jet of heat and very tiny bubbles above each of the 1/16" outlet holes. The idea here is that steam carries a ton of energy (2260 kJ/kg) and when it condenses in contact with a cooler liquid (wort/mash), the energy is released as heat. This is a highly efficient means of heating the strike water, maintaining the mash temperature, and ultimately doing precise step mashes. Will this drastically improve my beer? Unlikely. Was it fun as hell to build? YES. But, how well does it work?
Steam Test Alpha - using silicone 1/2" hose, and ball valves for steam control. Full recirculation for accurate temperature measurements
Boiler filled to ~80% capacity (8 gallons or so) of 43F water. Turn on 6kW element to 100%. 30 minutes later, we have about 5psi of steam and rising rapidly.
Mash Tun filled with 10 gallons of water
Time / Temp / Steam Pressure / Valve opening
00m 53F 35 psi 0%
01m 56F 33 psi Cracked 20% - seemed to surge
02m 59F 33 psi
05m 70F 33 psi
10m 86F 33 psi
15m 107F 28 psi 25% - reduced surging
20m 126F 25 psi 35% - no surging, steady steam injection
25m 142F 24 psi
30m 157F 22 psi
35m 172F 20 psi
To me, this is a fantastic result, but we found that there was far too much condensation in the 1/2" silicone, so we upgraded it to 1/4" copper hard tube for volume as well as safety reasons, allowing for higher steam pressures (not higher temperature, just more of it in the tank - reducing any recovery time, or pressure loss).
Steam Test Beta - 1/4" copper line, solenoid valve orifice 3/32", all valves wide open
Same ten gallons of water in the MT.
Time / Temp / Steam Pressure
00m 93F 50 psi
05m 110F 46 psi
10m 126F 42 psi
15m 141F 40 psi
20m 155F 39 psi
25m 168F 38 psi
Again, this is fantastic. Compared to what? Well I found that the HERMS system that I had used before was extremely slow, and didn't seem to be very efficient. I had troubles maintaining temps and overshot some with strike water. Maybe it was due to the 3/8" copper coil, I don't know. I think that this upgrade will greatly aid in the process. I imagine that heating the mash will be even quicker due to the density of mash versus 100% water, reducing the heat capacity of the whole.
One thing to note... at full throttle while injecting steam... this thing is noisy! The rumble from the MT is intense as the steam condenses and releases its heat. I love it!
Now I have brewed two batches on this system using step mashes (mostly just a protein rest at 122F, stepping to mash temp ~149F, then a mashout at 168F) and it has worked flawlessly. The steps are quick and painless, and heat distribution is easy since my pump is recirculating throughout the mash. Couple more pictures here for you guys...