Problems with my propane burner.

[Gretas Brew]

I recently bought a propane burner so I could brew on my back deck. The problem is the burner produces black soot (carbon) all over the bottom of my kettle. This black soot makes clean up a pain and a potentially life threatening mishap if I were to get that black soot on the carpet and could not clean it up before my wife saw it. My question is has this happened to anyone else and is there a way to combat this? Thanks for any advice.

[ihikeut]

There usually a shutter that is adjustable to allow more air to mix with the propane. Open and close it till you get the best flame.

[MaltLicker]

Pitch the idea of getting new carpet, and make sure it's dark.

[Wildrover]

Seriously though, why is that happening?  I've had three burners over my all grain brewing days and none of them have done that.  They have discolored my pot over time but producing black soot?  The only thing I can think of, and this may be a stretch, is that your burner is new and needs to burn off whatever chemical may have been put on the burner at the factory which may take a brew or two more until its all burned off.  other than that I'm at a lose? 

[brewfun]

Soot is caused by an improper mix of air and propane.

If the burner is clean at full throttle, but sooty when you turn it down, then it is probably getting too much air. Following Ihikeut's advice is the first thing to try. The flame does not have to be very tall to be really hot.

What you're looking for is a nice row of blue flames and the kettle to be a little above them. I once had to use cinder blocks and bricks to elevate my boil pot above the burner by about 1.5 inches to avoid soot.

If the venturi gate is not changing the flame correctly then it may not be big enough, or is designed to pull in more air when it's hot. Sadly, there are some poorly designed burners out there. In these cases, you have to aspirate the gas better. A needle valve where the line attaches to the burner will restrict the flow a little and still maintain the pressure.

[texasdan]

I have the same problem with my new 192K BTU burner.  I can't seem to get a clean blue flame no matter how I fiddle with the air control or regulator.  The sink where I chilled the wort was filthy with soot when done and the wife became very upset

This may not be a good solution for you, but I finally picked up a cheap pizza pan just slightly larger than my boil pot to sit on that can turn black for all I care. 
Now my boil pot stays clean.  I would guess if you have an aluminum pot you would use an aluminum pan. 
I really don't know if there would be some kind of metallurgical interaction if the pot and pan were of different metals or not.  Someone with metallurgical expertise would have to answer that.  So far I don't think it has affected my heat efficiency.

[merfizle]

One of my turkey fryer burners did that....couldn't get enough air and flame was yellow.

Mark

[Gretas Brew]

Thanks guys for your all your advice. I'm going to try and mess with the air intake and see if i can get a bluer flame. If that doesn't work I'll try the pan idea.

[Scott Ickes]

One more suggestion.  Propane tanks only need to be cracked open a little bit.  They do not need to be fully open.  If they are opened too far, the volume of propane going to your venturi can overpower it and cause just what you are describing.  Gas grills are the same.  Only crack open the propane valve on those too.

[Ramble]

I know this post is rather old, but I went looking for a solution to the same problem. I bought a cheap Turkey Fryer, and use it for that as well as brewing. It worked pretty well for a coupleasant times, but lately it has been not working well. I have to admit I have not treated it too well. Several boil-overs and being left outside for a couple years, and not working well. Tried adjusting the air valve, and flames actually shot out of the air valve. Quickly shut off propane. Figured this is a signthat the path is restricted. I couldn't get it cleaned with an air hose or a pipe cleaner, so I took the burner apart and used a wire brush to clean the spiral burner element and the gas-air mixing chamber and put it back toget her. It worked perfectly immediately after lighting it. Very simple construction, so as long as the bolts aren't too corroded, it should be an easy thing to try. Good luck!

[twhitaker]

 Soot means there is not enough oxygen/too much fuel in the combustion equation. Or impingement- pot too close to burner. Try raising pot.
I find IF you have cleaned the burner and there are no obstructions, and air shutter adjustments don't work, then the pressure regulator setting needs to be adjusted. Usually needs to be turned down, back out  the regulator screw under the cap a bit then play with air adjustments until nice blue flame with no yellow. Some folks also just crack open the propane supply valve to achieve this.

  You also need to supply fresh air to the burner and area / room.  Some cast iron burners require wire brushing to remove clogging rust and scale, then blow out assembly with air until its clean. Also ensure the gas orifice (nozzle;jet) is clear there should be just a small hole in it with no spiderwebs, run a small guitar string through the hole to ensure its not blocked.