Stupid or not - Direct fired wooden mash tun

As a quick disclaimer, this isn't a troll question

I ordered mineral wool to make a insulated keggle. I was originally going to use aluminum flashing to wrap around the wool to hold it in place.

I saw this picture and decided it would be cool to wrap the wool with wood instead:



I know people use wood for their brew rigs, so would it be possible to fire this tun (gently), or would the wood burn out?

I wouldn't risk it. It's an awesome look, but if you have a HERMS coil, you won't need to fire up your mash tun.

That's a super sweet mash tun! Great work on it. But I don't think I would use it in the current configuration with flame. You could build a metal lip around the base maybe to deflect the heat. I would imagine would work. It's not like it's the boil kettle or HLT that are exposed to heat for significant amount of time. I wouldn't want to try it without the heat shield lip.

You could add a RIMS system. They work nicely.

Dan said:

That's a super sweet mash tun! Great work on it. But I don't think I would use it in the current configuration with flame. You could build a metal lip around the base maybe to deflect the heat. I would imagine would work. It's not like it's the boil kettle or HLT that are exposed to heat for significant amount of time. I wouldn't want to try it without the heat shield lip.

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Its not my mash tun - yet! Just an image I found on google.

I'm going to build it if I get the tentative go ahead here. I can't imagine that the wood would spontaneously combust, but would just start charring at the worst.

Edit: Just found this chart for ignition temps. Oak holds up to 800F or so, which is actually comparable to the mineral wool. http://www.engineeringtoolbox.com/fuels-ignition-temperatures-d_171.html

bbrim said:

You could add a RIMS system. They work nicely.

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Well yeah I could - but I don't like RIMS tubes and even if I did I don't have the money for one. I'd do HERMS if I upgraded. So direct firing is my only option as of now.

Wood that chars, might start burning...lol.
Maybe get a 10 gallon igloo cooler and wrap that in wood until you can upgrade to a HERMS coil? No need to heat a cooler. Should hold for an hour, mine might lose 1 degree.

sarsnik said:

As a quick disclaimer, this isn't a troll question

I ordered mineral wool to make a insulated keggle. I was originally going to use aluminum flashing to wrap around the wool to hold it in place.

I saw this picture and decided it would be cool to wrap the wool with wood instead:

I know people use wood for their brew rigs, so would it be possible to fire this tun (gently), or would the wood burn out?

Click to expand...

Just a bit concerned for you. What sort of mineral wool are you going to use? Some (all?) of this stuff is akin to asbestos. Very nasty stuff if the dust fibres are inhaled - carcinogenic.

An alternative (not sure on the hazards) might be vermiculite. It is a clay mineral used in gardening. You'd need a few inches of it. Its very light. They use it in developing countries to insulate the chimney in 'Rocket Stoves' - highly energy efficient, smokeless cookers that use only a few twigs to cook a family meal.

OT: i like the pump shield too

sarsnik said:

I'm going to build it if I get the tentative go ahead here. I can't imagine that the wood would spontaneously combust, but would just start charring at the worst.

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of course it wouldn't spontaneously combust...but you do know that wood is flammable right? So when exposed to direct flames it will light on fire. Somewhere I read that a lot of ancient (and not so ancient) people's used wood as a way to create fire. You know....In the days before gas or electricity.....


I guess if you were really hell bent on this idea you could soak the bottom of it prior to heating in an attempt to not let the damp would catch on fire but then you'd worry about warping your pretty mash tun....I'd say only wrap it in wood if you were heating with some other method than fire...

A metal heat shjeld with an air space between the shield & wood would probably work. That's how I did it on my old rig which used foam insulation that had a relatively low melting point.

Not even touching on the flammability, I don't think wood would be very efficient at transferring heat, so you're going to need to apply more heat for the same temperature rise.

doghousechef said:

Not even touching on the flammability, I don't think wood would be very efficient at transferring heat, so you're going to need to apply more heat for the same temperature rise.

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The bottom of the keg would be exposed. I was simply thinking of strips of wood wrapping the rockwool. Wood is also a very good insulator, so it would also serve a functional purpose.

This guy here apparently fires his wrapped kettle.
http://www.homebrewersassociation.org/forum/index.php?topic=4368.0

Jmw5107 said:

of course it wouldn't spontaneously combust...but you do know that wood is flammable right? So when exposed to direct flames it will light on fire. Somewhere I read that a lot of ancient (and not so ancient) people's used wood as a way to create fire. You know....In the days before gas or electricity.....


I guess if you were really hell bent on this idea you could soak the bottom of it prior to heating in an attempt to not let the damp would catch on fire but then you'd worry about warping your pretty mash tun....I'd say only wrap it in wood if you were heating with some other method than fire...

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Funny, but doodybaggery nonetheless. He put a disclaimer in the title.

There was another quaint tradition the old folks had of READING THE FREAKING THREAD TITLE BEFORE ENGAGING IN BLATANT ****** BAGGERY!!!

doghousechef said:

Not even touching on the flammability, I don't think wood would be very efficient at transferring heat, so you're going to need to apply more heat for the same temperature rise.

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......ahem.....right you are........if the bottom was wood, which would be insane.....

Why not just insulate the top and bottom as well and mash in it like it was a cooler?

sarsnik said:

The bottom of the keg would be exposed. I was simply thinking of strips of wood wrapping the rockwool. Wood is also a very good insulator, so it would also serve a functional purpose.

This guy here apparently fires his wrapped kettle.
http://www.homebrewersassociation.org/forum/index.php?topic=4368.0

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Oh, I thought you were going to directly fire the wood. With that in mind, I don't see any problem as long as you don't have direct contact with flame

cheezydemon3 said:

Funny, but doodybaggery nonetheless. He put a disclaimer in the title.

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i guess it was a little on the dickish side...wasnt intentional, just making a point. i forget how easily sarcasm can be lost over the interwebz

Jmw5107 said:

i guess it was a little on the dickish side...wasnt intentional, just making a point. i forget how easily sarcasm can be lost over the interwebz

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No worries, I appreciate dry humor.

I'm going to try it, then report back. Unfortunately the rock wool won't be delivered until monday.

Jmw5107 said:

i guess it was a little on the dickish side...wasnt intentional, just making a point. i forget how easily sarcasm can be lost over the interwebz

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Now, don't you feel better?

my posts too are often misintrapulated among the amazing intracacifications of the interwebz.

do you do step mashes? that is the only reason for direct fire... Most/all conversion in a 5-10gal batch is done withing 20-30 min. In witch case you really don't need to heat the MLT at all. But, if you must, I'd be more inclined to use a make shift herms by dropping an immersion chiller in your HLT and recirculating hot water to raise temps. Fire and wood Burn. and even a char on something that pretty would IRK me to all get out. Good Luck

fletchsj said:

Most/all conversion in a 5-10gal batch is done withing 20-30 min.

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Damn. I've been mashing for 60 minutes since I started. Guess I was wasting time.



(sarcasm)

Hang Glider said:

Damn. I've been mashing for 60 minutes since I started. Guess I was wasting time.



(sarcasm)

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I normally mash for 90.....

With modern malts they fully convert in a much faster time frame. look up the specs of the grain you use. Most, if not all of the commercially available malts convert very quickly. so I guess you might be wasting time. it's not a knock, to each their own. If you are growing and malting your own grain then the inconsistencies might deserve a long mash and/or a step mash. Just trying to help out. good luck. I run iodine tests regularly and frequently get complete conversion in 20-30min.

if your long mashes are for another reason other than starch conversion... please enlighten me as I am always interested in learning a new technique.