Insulating a Brew Pot for faster more efficient boils

[backyard brewer]

I've not seen one in person but several well documented ones on the web. They really do seem pretty nice. As I keep looking at my kettle that needs all the soot scrubbed off it again.... I think maybe electric wouldn't be so bad. Craig converted his pool filter system to an electric HLT but still uses dual propane burners for the boil. He has a timer on his HLT that starts heating things an hour before he even wakes up. Can't really do that with a gas fired system. Not with a safety factor I'd be comfortable with anyway. You can also use a PID or PID routine which doesn't lend itself well to a gas system.

I dunno, I'm pretty intrigued but I'm not sure you can get enough power (reasonably) to a boil kettle at 20+ gallons though. I guess it also depends on where that particular power consumption falls on the stupid Edison tiers. Think about all the pluses though:

No noise.
No CO emission.
Stand doesn't get scorching hot.
Things you don't want to be on fire don't light on fire.
Much more straight forward control of temperatures.
Safe for indoor use, assuming you can remove the steam.
theoretically more efficient since more energy can be focused where you want it.
You could design the vessels with drains instead of side siphons.

I guess a bunch of math would be in order to figure out just what it would cost to run. I'f it's like running an A/C for three hours that would be fine. If it's like running a welder for 3 hours.... well, maybe not so much!

[maltbarley]

I'm surprised you guys aren't talking bout installing a boiler so your system can use steam heating. THAT'S how the big boys play.

[JonGoku]

Although it appears a lot of you are skeptics, my suspicion is that insulating my aluminum pot will cut down on my time-to-boil by 30-40% which would translate into about 20-30min. This wold be more then enough benefit for the trouble. Once I figure out a a material to do the insulation I will preform test comparisons and post pictures and the results.

[dhempy]

I'm surprised you guys aren't talking bout installing a boiler so your system can use steam heating. THAT'S how the big boys play.

HomebrewTalk's version of our BackyardBrewer has tinkered with steam and it uses an electric element! I wonder How many solar panels would one have to have to generate enough electricity to neutralize the effects of an electric element.

Jon: Good luck ... we love trail "blazers" around here! I'm looking forward to seeing what you turn up with your experiments.

Dan

[backyard brewer]

Although it appears a lot of you are skeptics, my suspicion is that insulating my aluminum pot will cut down on my time-to-boil by 30-40% which would translate into about 20-30min. This wold be more then enough benefit for the trouble. Once I figure out a a material to do the insulation I will preform test comparisons and post pictures and the results.

I hope you do figure something out. I hate wasting as much energy as I do on my system. I'm replacing the 23 jet burner with a 10 jet because the efficiency just isn't worth it. It's consuming more than twice the fuel but not cutting the time in half. I think you hypothesis is dead on and well proven; focusing energy into your target medium and minimizing waste is always more efficient. I hope I'm wrong, but my prediction is once you do find a material that will work, the CBA will not warrant its use.

I really hope you find something though.

[backyard brewer]

Here's another hypothesis:

Insulating the walls of your kettle without refocusing your heat into the pot may reduce your efficiency, increase your heating and boiling times and use more fuel. Dan's heat shield comments keep ringing in my head.

Follow this logic: The heat that is not going into the kettle is washing up the walls of the kettle. This is obviously heating the air immediately around the kettle walls to a much higher temp than the wort. Since the kettle walls are being indirectly heated from the burner wash, heat should be travelling from the kettle walls and into the wort (hot -> cold). Therefore, insulating the kettle walls would actually prevent the kettle walls from being heated, preventing them from heating the wort and reducing your efficiency. Insulating the walls would reduce the surface area being used to transfer heat from the burner into the kett'e/wort to just the bottom of the kettle. During chilling it would also trap heat and increase chilling times as you already pointed out.

I guess the bottom line is this: Are the kettle walls being heated by the wort inside the kettle or the super heated air washing across them? I'm specualating the latter, not the former.

This should be an interesting bunch of experiements. I would suggest that rather than looking at insulating the kettle walls you look at focusing the heat into the kettle . Maybe look at a way to trap more of the heat wash around the kettle and hold it there a little longer, especially in the winter. Instead of insulating the kettle walls, insulate the air immediately around the the kettle walls in a fashion that slows down the replacement of that air by the burner. Kind of like placing your kettle in a chimney that is designed to slow the airflow around the kettle.

I'm picturing a second kettle of larger diameter, maybe 3" larger ID than the OD of your kettle leaving 1.5" airspace all around. Cut the bottom out to fit the OD of your boil kettle. Drill several exhaust holes around the circumfrence on the shield kettle all at what was the bottom. Invert the shielding kettle and drop the boil kettle in it so the bottom is all open and the exhaust holes are at the top.

[backyard brewer]

This would be easy to test. I might try it this week or next weekend.

Bring water to a boil in the kettle.
Measure the temperature of the water immediately adjacent to the kettle walls at several levels in the kettle.
Measure the temperature of the water in the center of the kettle at the same levels.

If the water at the kettle walls is heating faster than the center water column, then we'll know that heat is entering from the kettle walls not exiting and insulating them would be a mistake.

[JonGoku]

Right, keep a tank in the grill and one for the brew system. The grill tank is my backup.

Lol, what do I do if the only tank I have is the one I stole from the BBQ.

Here's another hypothesis:

Insulating the walls of your kettle without refocusing your heat into the pot may reduce your efficiency, increase your heating and boiling times and use more fuel. Dan's heat shield comments keep ringing in my head.

Follow this logic: The heat that is not going into the kettle is washing up the walls of the kettle. This is obviously heating the air immediately around the kettle walls to a much higher temp than the wort. Since the kettle walls are being indirectly heated from the burner wash, heat should be travelling from the kettle walls and into the wort (hot -> cold). Therefore, insulating the kettle walls would actually prevent the kettle walls from being heated, preventing them from heating the wort and reducing your efficiency. Insulating the walls would reduce the surface area being used to transfer heat from the burner into the kett'e/wort to just the bottom of the kettle. During chilling it would also trap heat and increase chilling times as you already pointed out.

I guess the bottom line is this: Are the kettle walls being heated by the wort inside the kettle or the super heated air washing across them? I'm specualating the latter, not the former.

This should be an interesting bunch of experiements. I would suggest that rather than looking at insulating the kettle walls you look at focusing the heat into the kettle . Maybe look at a way to trap more of the heat wash around the kettle and hold it there a little longer, especially in the winter. Instead of insulating the kettle walls, insulate the air immediately around the the kettle walls in a fashion that slows down the replacement of that air by the burner. Kind of like placing your kettle in a chimney that is designed to slow the airflow around the kettle.

I'm picturing a second kettle of larger diameter, maybe 3" larger ID than the OD of your kettle leaving 1.5" airspace all around. Cut the bottom out to fit the OD of your boil kettle. Drill several exhaust holes around the circumfrence on the shield kettle all at what was the bottom. Invert the shielding kettle and drop the boil kettle in it so the bottom is all open and the exhaust holes are at the top.

Thanks for taking the other side of the debate. In answer, what about this... If the Aluminum pot is actually hotter then the hot air coming up the sides would the drafts of hot air coming up the sides be actually cooling the pot instead of heating it? This is getting interesting.

Anyways, I was not assuming to only insulate the pot and not also focus the heat from the burner, but to do both at the same time. It will be interesting to see how much difference both of the modifications make on their own and then how they work combined.

I hope you do figure something out. I hate wasting as much energy as I do on my system. I'm replacing the 23 jet burner with a 10 jet because the efficiency just isn't worth it. It's consuming more than twice the fuel but not cutting the time in half. I think you hypothesis is dead on and well proven; focusing energy into your target medium and minimizing waste is always more efficient. I hope I'm wrong, but my prediction is once you do find a material that will work, the CBA will not warrant its use.

I'll have to see how the CBA works out, but I think I may have found someone who will give me some scrap material for free.

Cheers!

[backyard brewer]

Thanks for taking the other side of the debate. In answer, what about this... If the Aluminum pot is actually hotter then the hot air coming up the sides would the drafts of hot air coming up the sides be actually cooling the pot instead of heating it? This is getting interesting.

Well that's my point exactly. I'm confident the hot air drafts coming up the side are hotter than the kettle. The exception would be windy and/or cold days when cross drafts are blowing the hot air away. I know this for fact because if it's a cold day and I open my gate, the breeze up the side yard will knock my kettle off boil. Without measureing anything, I would guess the hot air drafting up the sides is a couple hundred degrees. I know, again for fact, that a wooden mash paddle left too close to the burner will catch fire, so I'm guessing several hundred degrees at the bottom and cooling as it rises but probably still a couple hundred.

I believe the thing to do is insulate the hot draft air coming up the sides of the kettle and keep it there, not insulate the kettle itself. Basically create more of a draft shield than insulation.

[JonGoku]

Ok, by no means am I ecstatic with the material I got, but it's hard to look a gift horse in the mouth. The material looks very insulative, and it is indeed fireproof, but the durability is a bit skeptic. Feel wise the material is like a nonsticky "blanket version" of cotton candy. By that I mean it is soft and mauluable, but does not rebound or return to it's original shape if compressed. Originally it was about 2" thick however it is layered liked and can be peeled into thinner layers. I ended up peeling it in half to try and get a 1" thick layer. It is not complete but check out the two picks below.

I plan on picking up some aluminum tape this evening and wrapping the outside and top edge to increase it's durability.

Insulated Pot.jpg (48.48 KiB) Viewed 2218 times

The "jacket" comes down over the burner to form a short skirt and hopefully funnel or trap up some extra heat underneath the pot.

Insulated Pot 2.jpg (31.65 KiB) Viewed 2218 times

I may have to make a few holes in the skirt area to maintain the flame, but I'll test it this way first to see how it goes.

Cheers!

[JonGoku]

I picked up some HVAC Foil tape at Lowes this afternoon and made out like a bandit. I got a 50yrd roll of 2.5" wide tape for $7.28+TAX. The items were miss shelved and the price below them showed what I paid, but they were ringing up at just under $16.00. I complained at the difference and they marked it down to the price listed on the shelf.

HVAC Foil Tape.jpg (76.12 KiB) Viewed 2202 times

This stuff is rated up to 250*F so it should be safe enough on the outside of the insulation.

Side Note: Sorry for the crappy photo's. I wish America would catch up the the rest of the world when it comes to the quality of cellphone cameras.

[Marotte Brewery]

it is indeed fireproof

I would be very careful with this. Most times "fire-proof" means that the material will not actually catch fire, but it might melt, or otherwise disintegrate at high temperatures...

[JonGoku]

I had a bit of a set back and not sure what path to take next. I may end up going with BB's concept of a double shell or something that may help trap the heat next to the pot as the material I got did not hold up. It's late and I'm tired so I'll think it over some more later on. Some pictures of the burned material below.

The top flappy parts is actually the bottom with the foil tape that was wrapped around the bottom edge peeled back to see the burned areas.

Burnt Material 3.jpg (71.93 KiB) Viewed 2180 times

Burnt Material 1.jpg (66.22 KiB) Viewed 2180 times

Burnt Material 2.jpg (65.9 KiB) Viewed 2180 times

I only ran the burner for about 3-5 minutes and there was smoke coming up the sides and it was smelling a bit unhealthy. I was slightly concerned about using this material from the start but I guess I wanted to be optimistic and give it a shot.

Oh well, back to drawing board...

[JonGoku]

it is indeed fireproof

I would be very careful with this. Most times "fire-proof" means that the material will not actually catch fire, but it might melt, or otherwise disintegrate at high temperatures...

Jeremy, feel free to throw in an "I told you so".

[Marotte Brewery]

it is indeed fireproof

I would be very careful with this. Most times "fire-proof" means that the material will not actually catch fire, but it might melt, or otherwise disintegrate at high temperatures...

Jeremy, feel free to throw in an "I told you so".

You already did...

I'm just glad that you decided to "test" this first before trying to brew with it and possibly ruin a batch of otherwise good beer.