• Smokey and the brisket: build a steel braai

    • PM's Mike Allen built this offset-firebox smoker in a weekend. It burns a combination of charcoal and hardwood to produce classic, slow-cooked barbecue.
    • Smokey and the brisket
    • [1] Lump-style charcoal [2] Firebox damper door [3] Firebox with tight-fitting door [4] Smoke chamber with chimney [5] Stainless steel grill [6] Seasoned oak and apple wood [7] Dinner - in about 4 hours
    • The chimney is 75 mm chimney pipe
    Date:31 August 2006 Tags:, , , ,

    You will not learn anything useful about good barbecue from recipes in the back of women’s magazines…

    When man first mastered the art of making fire, it’s a reasonable bet that his second words (the first being “Woohoo”) were something along the lines of: “Are you sure you want that mastodon sirloin well done?”

    For, whatever our cross-boundary differences, human beings across the globe are united in a common bond: we love to cook our meat over the coals. Each nationality may have its speciality – the Asian tandoor, the US barbecue or the good old South African braai.

    Although barbecue has become a generic term for outdoors cooking, in fact it’s an art form fashioned in the American south.

    BBQ-style cooking probably developed when people who couldn’t afford the better cuts of meat were forced to consume tougher, fattier cuts such as pork butt and beef brisket. The secret is to cook these cuts very slowly, over a duration of 4 to 6 hours or longer at temperatures near the boiling point of water. Two marvellous things happen when you slow-cook at low temperatures: the tough meat becomes flavourful and succulent, and the fat is rendered out, in sort of a self-basting. A fringe benefit is that the low, smoky fire leaves the aroma of smoke permeating the meat. I burn mostly oak, but my favourite is apple, when I can get it. Any fruit or citrus wood is good. Hickory makes everything taste like bacon, so I use it sparingly. Never use pine, any softwood or any finished lumber (like old furniture).

    Don’t confuse this low-temperature smoke cooking, which is the essence of BBQ, with cold smoking. Meat that’s meant to be preserved by curing with salt or honey and low moisture is also smoked, but in that case the temperatures don’t go above 50 degrees or so, and the smoking period is measured in days, not hours. A properly cured ham can hang at room temperature for months without spoiling – BBQ is meant to be enjoyed immediately.

    Traditional BBQ smoking is done in a brick pit, but there are all manner of commercial smokers on the market, ranging from very inexpensive sheetmetal water smokers to giant commercial-quality stainless steel contraptions the size of a small car (and costing almost as much). A good cook can make good BBQ in anything. I’m not even going to touch on the dry-rub-versus-mop debate, the ketchup-versus-vinegar-based BBQ sauce controversy, or whether to baste. I decided after years of working with a small water smoker – and recently acquiring a vacation house – to build one of my own. This project involves a lot of welding, which might seem daunting. Maybe, maybe not – I’m a certified welder, so it was easy for me. Several wirefeed welders are sold at hardware and tool suppliers, and you can learn to do simple welding with only an hour or two of practice. Salvaged materials will be fine for your smoker’s frame. You can use old water pipe, rebar or even electrical conduit.

    I constructed my smoker out of 10-gauge sheet steel on a frame of 25 mm thinwall square tubing. One caution about barrels – unless you can acquire a genuine foodgrade barrel, make your own. Any barrel that used to contain noxious industrial chemicals is not a good option, unless you want to grow another eye on your elbow. I used heavy-gauge steel (just under 3 mm thick) to ensure a long service life and to add thermal mass for all-day, slow fires. The round cross section I made isn’t necessary – a square or rectangular one will cook just as well, although it will be a little tougher to clean.

    Our smoke chamber is 90 cm long x 45 cm in diameter. I made the firebox 30 cm long, which adds up to exactly the width of a standard 1,5 x 3 m sheet of steel, minimising waste. Conveniently, these are exactly the dimensions that allowed me to use some stainless steel racks meant as a replacement part for a Weber grill. You’ll need simple hand tools, a welder, a 10 cm angle grinder and a sabre saw. I lined the bottom of the firebox with a layer of fire-brick to keep the box from burning out too quickly and to conserve heat.

    I made the smoker so that it can be conveniently broken down into three parts: the firebox, the main smoke chamber and the frame. Collectively, they weigh nearly 50 kg, but handles on the smoke chamber make it easy for two people to tote around. Clever use of wingnuts means no tools are needed for assembly. Be prepared to be invited – with your smoker – to lots of outdoor parties.

    Despite all the doors being well-sealed, the nature of liquid smoke is to dribble out of every crack and off the bottom of the smoke chamber. This will permanently stain your deck even if the wood has just been sealed. I suggest making a large tray out of sheetmetal, with a raised lip, to go underneath. I installed a drain petcock in the smoke chamber to aid in cleanup.

    We’ll clean up after we finish dinner, thank you.

    You can now buy a 230 V wire-feed welder for a very modest price. All of the welding we did on this project was done with 0,9 mm flux-cored wire, although you can gas weld if the metal you choose is thinner. Alternatively, if you have an arc (stick) welder, 10 gauge is about as thin as you can weld successfully.

    I welded the ends on first, keeping distortion to a minimum, and then cut the holes for the doors. A 5 cm holesaw gives nice rounded corners. I had to cut only three-quarters of the way around the openings because I used the unwelded seam for the bottom of the door. The steel can be cut with a sabre saw, but it’s laborious and consumes a lot of blades. I also tried cutoff wheels on the grinder, which was somewhat faster, although it threw a lot more sparks. Next time, I’ll beg, borrow or steal a plasma cutter.

    We had a local sheetmetal shop cut the pieces to size and then roll the drum sections for us. You can use just about anything made of steel – as long as it’s not galvanised. If you can find one, try a food-grade steel barrel.

    An inexpensive piano hinge keeps the doors tightly sealed. I used pop rivets, but sheetmetal screws would work. Wooden handles, which stay cool enough to touch, are held in place by bolts and brass spacers. The handle was sanded and paste waxed.

    The chimney is 75 mm chimney pipe [see above]. The low-tech firebox damper is the end of a soup can. The connection between the firebox and smoke chamber is a 50 mm water pipe, with the collars from a pipe union for nuts. The firebox hangs from this connection, which is surprisingly airtight. A bolt and wingnut lower down keep everything solid. With everything assembled and painted, it’s time to build a hot fire in the firebox, and get all the metal hot enough to set the paint and burn off any mill scale and cutting oil lingering inside. After it all cools off, wash everything and paint the inside of the smoke chamber with vegetable oil to prevent rusting.

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