31 replies to this topic

[ChefLamont]

I would definitely try to figure out a wind screen. That will save a bunch.The other thing has to do with process. Blktre is right, when you crank the burners up to "11" they get much less efficient. So, I have learned to be more efficient in process. For example, I start heating the sparge water over a gentle flame with ~30 min left in the mash. That way it is right about where I want it (usu. boiling) when the mash is done. Also, I started heating the boil when the sparge (fly) is about half done. Again, over a lower flame. Just those little things can save a fair amount.Not only does that save gas, but when you get good at the timing, it can save time too.

[davelew]

Or, alternatively, you could:(this pic was from halfway through construction; there's a grounding wire and more insulation on it now)

[djinkc]

Or, alternatively, you could:(this pic was from halfway through construction; there's a grounding wire and more insulation on it now)

Yeah, I remember seeing that one. Sweet but the unprotected connections, which I assume you have taken care of, scared me. I would really like to have an AC kettle that the element was not in the way. I like what I have but like anything, nothing's perfect.Who was that guy in Canada that had zip ties holding on the boxes for two 240v elements. Hope he's still with us.........

Edited by dj in kc, 26 July 2010 - 06:18 PM.

[3rd party JKor]

Or, alternatively, you could:(this pic was from halfway through construction; there's a grounding wire and more insulation on it now)

What are the band heaters rated?

[davelew]

What are the band heaters rated?

1600W each, so I can do 1600/3200/4800 watts. I usually do 4800W to get to a boil, and then 3200W to keep at a boil and avoid boilovers.

[3rd party JKor]

1600W each, so I can do 1600/3200/4800 watts. I usually do 4800W to get to a boil, and then 3200W to keep at a boil and avoid boilovers.

I like that design. How are you insulating the heaters, electrically and thermally?Also, where'd you get them?Also, part deux, does heating it from the sides like that give it a weird boil pattern?

Edited by JKoravos, 27 July 2010 - 08:23 AM.

[davelew]

I like that design. How are you insulating the heaters, electrically and thermally?Also, where'd you get them?Also, part deux, does heating it from the sides like that give it a weird boil pattern?

The heaters I got were industrial surplus (translation: my company was moving, cleaned out some old labs, said we could take whatever we wanted out of a dumnpster, and I grabbed some heaters that we had used to mimic the cooling load of a supercomputer on a liquid cooling system). There's a similar heater for sale in McMaster-Carr, part 3671k69, but I'm not sure it's identical.The actual heaters electrically isolate the surfaces of the heater from the voltage, so all I needed to do was electrically isolate the power connections and ground the surfaces of the heaters. I used a thermal grease that was mildly conductive to get the ground connection, and I bought a piece of teflon rod which I drilled and tapped to isolate the power connections. I attached a ground wire attached to a handle (I just drilled and tapped the handle and screwed on some high-temp wire) that grounds the boil kettle and all three heaters.As for thermal isolation, one side of the heater is thermally connected to the BK which is full of wort, and one side is exposed to the air. One of those connection has MUCH lower thermal resistance than the other. I don't bother with thermal insulation that would just increase the thermal resistance to the air, since the thermal resistance to the air is already so high that most of the heat flows into the BK (think of a 100 ohm resistor in parallel with a 1 ohm resistor, most of the current goes through the 1 ohm resistor, and increasing the 100 ohms to 1000 ohms won't add much power to the 1 ohm resistor).Yeah, there is a weird boil pattern, with convection currents going up along the outside, in towards the center, and then down the middle of the BK. The hops and irish moss tend to collect at the middle of the top of the pot. Since all the liquid is continually forced past the hops instead of just being randomly circulated, I thought I might get slightly better hop utilization, but I haven't really tasted a difference.

[davelew]

Here's a more recent pic, where you can see the white teflon homemade nuts, some black silicone covering other exposed 120V surfaces, and the grounding wire:

[3rd party JKor]

Looks good. I may consider that for the next revision of my system.

[3rd party JKor]

People who use propane should start weighing their tank before and after and we can compile some data on how much the average brew consumes in propane.

[MyaCullen]

People who use propane should start weighing their tank before and after and we can compile some data on how much the average brew consumes in propane.

if you had posted this 2 hours ago i could have complied next time time i will, as well as try to notate exact burn times