Scrap wood powered wort boiler

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Well-Known Member
Feb 14, 2007
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Aurora, IL
I'm planning on making a scrap wood fueled wort boiler out of a metal milk jug and the blower out of a shop-vac. I throw away tons of scrap wood and pallets every day at work. I figure that instead of rotting away in some landfill, it could be boiling my wort.

It is roughly the same principle as a blast furnace for smelting iron ore, just on a smaller scale.

Is there any reason why you guys think this wouldn't work, or would advise against it?

Forgive my crude Paint drawing.
I like the design. Ive been thinking of something along those lines. I see so many pallet get throw out and I just think of boiling wort.
Holy Crap, that is a lot of brew!

You have to be right though. I mean how else would they have heated the wort back then? I'm sure the smoke would only impart a minimal flavor in the beer as it is always going to be rising up around the kettle. I'm going to be burning mainly hardwood scraps, not pressure treated or anything, so it should be ok.

Has anyone else tried this?
I believe Kaiser(?) had photos of his trip to Germany where he visited a small village brewery that still used the original wood-heated brew-kettle. There's pics posted somewhere here on HBT.
wilserbrewer said:
Shop vac is a lotta air IMHO. I think you would have to gate it off or somehow throttle it back or you'd be blowin ash out the top??

Yeah I bet a small fan would be plenty of air....I just wonder how the milk can would hold up.
This German home brewer is doing it as well:

It should work nice for boiling, but step mashing is tricky, though possible with some practice.

You would definetely need some way to throttle or dampen the fire to control temperature. If you provide an air inlet below the fire as drawn, even without a fan you are going to get a tremendous breeze just from combustion causing the wood to burn harder. If your ash is going to drop away, you will lose some of the heat potential of the coal.

Still, it looks like it could be done, beer has been around much longer than propane or electricity.

Sure this may be a way to use up some scrap wood or to save a little money from propane or whatever. But wouldn't it make your brew day just that much longer? You'd have to build the fire, maintain it, and then put it out...sounds like more work then necissary. Especially when turkey fryers are pretty cheap. Just my $0.02
I think the concept is pretty cool. I would put a smoke stack on it to vent the smoke away from the wort. That way it isnt in your face every time you need to check the boil. I think you would only need the blower to get the wort to boil, once boild I believe natural convection would be plenty to maintain a good boil.
I doubt if you'll need any kind of forced air. A 4" tube with a damper in it to regulate the air flow would probably be enough.

My mother's father made a water heater out of a couple milk cans when the milk company switched to tanks. Burned corn cobs in it. Boy did that stink! And going out on the second floor porch in the winter to fire it up. Great fun when you're 5-6 years old.
Alamo_Beer said:
Sure this may be a way to use up some scrap wood or to save a little money from propane or whatever. But wouldn't it make your brew day just that much longer? You'd have to build the fire, maintain it, and then put it out...sounds like more work then necissary. Especially when turkey fryers are pretty cheap. Just my $0.02
Yeah it would take longer and might be more work but I would enjoy being outside and playing with fire!
+1 on playing with fire! I have been thinking of a wood stove or pot bellied stove and old pallets myself.
Is forced air really required? I've heard of it being used for small forges, as in melting down metal and casting. Even those setups use smaller squirrel cage blowers that put out less air than a shop-vac. I'm thinking you'd have too much heat which would lead to scorching and premature failure of kettle and burner. I do like the idea of using scrap wood as fuel though.
Yeah, maybe the forced air is overkill. Plus the extra electricity used for the fan might negate the free source of fuel.

All I know is that my current burner is drastically under-powered. It was a turkey cooker on clearance at Lowe's (probably for good reason, the pot developed a pinhole leak after about four uses). It took me more than an hour today to get 6 gallons of wort to boil... only after adding some supplementary heat from my propane torch. Not to mention the freezing rain and wind. God... one heck of a day. :mad:

Regulating the temperature cannot be that hard, I'd have to control the amount of air or fuel somehow. Most likely with a butterfly valve on the intake side, or maybe a simple piece of steel plate on the top to control how far it is open. (a throttle of sorts)

This will be my project for next week. I'll keep you all posted on the results.
If you could manage to brew a batch of beer and smoke a rack of ribs or pork shoulder all simultaneously than I would be truly impressed!!!
wilserbrewer said:
If you could manage to brew a batch of beer and smoke a rack of ribs or pork shoulder all simultaneously than I would be truly impressed!!!

Now THAT'S what I'm talkin about!!!
except make it a brisket
Do not use a milk can. It will not withstand the amount of heat generated.

Instead, use a scrap water tank. A pressure tank for a well will work fine. Do a Google search for waste oil heaters and fine the Mother Earth News plans for a waste oil heater made from a scrap water tank. You should be able to modify this principal to wood and have a stout enough burner housing to handle the heat.

I built a waste oil heater from an old well tank, probably a 150 gal tank or so. I've had the sides bright cherry red without any problems other than too much heat! These old well pressure tanks are built heavy and can withstand lots of heat and a heavy top load.

Scrap the "turbo charger" vacuum motor except for start up. A small computer muffin fan will supply more than enough air, probably too much. Use a variable air throttle and build the assembly as airtight as possible for the best results on controlability. If your brew kettle is to sit down into the fire chamber, build that mount tight as well.

Make an exhaust stack to carry away the fumes and to provide positive airflow characteristics. It should also keep your beer cleaner.
You will get a little smoke flavor in the brew (think aromatic cigar type effect).

My second batch was a Nut Brown extract kit brewed on a firepit on a whim. I had been sitting out enjoying the fire and some beer when I started thinking about that extract kit. I knew the fire was hot enough to boil water so I gave it a damn brew night as of yet (12 batches now).

Good Luck
your brewpot will need a hat to keep ash and embers out of it. Like a lid on stilts to let the steam out. a blower would be great for the initial heating of the wort. You could get it boiling mighty fast. Still I agree with the others in that you'll need to be able to dampen the fire more than add extra air. Your first couple of runs may very well be complete boil over disasters, but I'm sure you can figure it out.
I'd be tempted to go with a "turbo" stove design There are lots of other pages out there if you search

I read up on these a while ago when I was looking to make my pig cooker. What I liked was turbo stoves are VERY efficient and clean and thorough burning. Efficient enough to boil a pot of water with the heat from a single sheet of newspaper! I ended up going another route. I still may build one of these to fire my cooker though. I'd save a lot in charcoal and could spend less time tending the cooker and more time drinking beer
I think you could build something that burns clean enough. Gasification is good enough to get the complete/clean burn of anything you put in it. Then you could just heat a "flat top" of a lid to your burner and that would in turn heat your kettle. then the only thing open to air would be your fire box door with your fan inlet and your exhaust stack outside. The draft should keep any smoke out of your beer even when opening your firebox door, and the gasification of materials is clean for the environment and more efficient for you. Just an idea. I may think up something like this for my permanent setup one day.
Just came across this thread and I'm thinking of doing the same thing, and it also give me a chance to sing the praises of the rocket stoves!!

If you haven't heard, it's an incredibly efficient wood burning stove! Search for institutional rocket stove--used to cook/boil large volumes for communities.

If you use a skirt around your pot, and a properly drafted chimney, you'll have no problem boiling wort and use minimal fuel. Some say it burns really hot, but not for very long, I disagree. If you do some searches, some folks use these to heat their houses by burning them for hours to heat up brick/concrete/cob masses in their house. With this being said, those designs offer ways to stock the stove for long periods and if you need to reduce the flame, simply pull some wood out, or adjust the airflow.

I want to building some slim models that I can build into a single tier/multi-keggle system to heat the HLT and Boil pot. Once I figure out how to adjust the flames and heat with these two vessels I'll probably try to make one for the Mash tun.

Research will show you that these can burn up to 1200 degrees in some well made instances!

Great info out there on rocket stoves. Seems like you could make a great wood fired pizza oven with this concept. Here is a link Seems like you could build a dome over it and line it with quarry tile. Also looks like you could make one for the boil kettle.

that's gonna cost you a wee bit more then $15 bucks.

Living in the north west I can't brew outside all year long on something like this. now I most certainly understand its just another option and its not for everyone. Its still gonna cost.