Build the best smoker

Home built fan-assisted hot and cold meat/fish smoker
By Rod Kane

The smoker...
Detail: Note temperature probes in door (with double-glazed window), front wall and side wall (for piercing into salami) and smoke generator column (bottom front)

Cold smoke, hot smoke
Cold smoke is generated at a distance and pumped to the food which has no heat source near. Cold smoke cures hams and meat cuts the old-fashioned way and the smoke generator alone has to be run for many hours and even days at a time.
Hot smoke is generated by a heat source close to the food and cooks it at the same time. The most popular form of smoking for the average Kiwi is hot smoking, with a heat source inside the smoker to create the smoke, usually from sawdust on a tray on a ring burner or in a smouldering fire. But this can mean continually opening the door to replenish the sawdust. The smoker I have built allows me to have heat when I want it in very small amounts with everything more controllable with a separate smoke source. The smoke flavor can be delivered at a low temperature, even in summertime, without opening doors.

Build a smoker
Some time back I built the excellent pizza oven featured in this fine magazine and it provided weeks of building pleasure. We have had many evenings of entertainment where we cook everything in it we can think of (in the learning stages, I use the term “cooking” very loosely).
It was almost a shame to finish it and I I have pined ever since for something like it. There are just so many pizza ovens you can fit in a backyard. As keen try-hard fisherman and someone who lives for spicy food, I wanted to get into smoking fish and salamis as well as cheese, sausages and hams, with taste and preserving the product being the main goals.
A smoker was the answer. But I found the smokers out there mostly either industrial-size or too small or too hot...or whatever. Nearly all lack character. I wanted something big enough to smoke the mythical catch, yet small enough to smoke a few kgs of salamis well. It had to be a hot and cold smoker. I also wanted something economic to build, using off-cuts and bits and pieces. The 0.5 cubic metre interior volume I chose for the smoker box, conveniently, could be made from just two sheets of ply, one treated, one untreated.

Smoker broken down for transport

Everything
I wanted the smoker to break into three parts for easy transport to the bach, to be compact, strong, weather-resistant, fully insulated, on wheels, have a cold smoke source outside the box for fish smoking and a separate heat source inside for salamis. It had to have everything on board, be easy to control delicate temperature ranges at the low end, be simple to build and most of all be a fun project. Happily it is all of those things. It also embodies all the elements of smoke, flame, whirring fans and even a hint of steam which almost places it in the worship category.
A few years ago I would have added a fridge, bar, TV and boat-washing station but time, evolution and an uncooperative liver has put paid to those days.

Square up sides

Window fan
Make it to any style you like but DON’T skip putting in the window or fan.
• The window means you never have to open the door, with all the obvious pluses.

• The fan makes a huge difference to performance, saving gas and many hours.
I could hardly believe the difference these made.

Dovetails? No—it is an easy build and you could add your own refinements (“steam punk” is in, I’m told). Everything is glued, clamped and screwed for strength, rigidity, weather-tightness, air-tightness—if this is good enough for the De Havilland Mosquito then it’s good enough for me.
I use Gorilla glue which is quick-setting, strong, waterproof and expands to fill gaps. The inside is all untreated ply or off-cuts, the outer skin is treated ply. I kept a 25 mm cavity between the ply inner and outer and filled this with insulation. There is a solid wood filler sandwiched in between where an aperture had to be drilled through for temperature probes, etc.
The door is double-glazed, the combustion box lined with cement/fibre board and there is a home-made damper in the flue at the top which does all the fine temperature adjusting, plus-or-minus only a degree Centigrade here or there. With the single-ring, double-row burner, I use mostly the small inner row of flame only. This tiny flame is well away from any timber and small adjustments make the temperatures rocket.
I have three temperature gauges. Two measure the smoker through the door and the front wall (one probe is very accurate) and another probe actually goes through the side wall and into the meat. You can view all from the outside at eye level. The temperatures are lowish for fish, higher to cook the salamis (see elsewhere in this article, Making salamis). To try it out for fish, I smoked Kahawai and for The Shed magazine Hapuka (see elsewhere in this article, Smoking fish).

Insulation sandwiched between inner and outer walls

Building wall with door in it

Cutting food rack supports

Wood
You could make the inside of the smoker out of anything harmless really, board and batten, cement board etc and you could line it with galv sheet easily enough, which would no doubt contain the heat even better, add to its lifespan and make it easier to keep clean. I didn’t do that because although I keep my BBQ immaculate, I have only ever seen smoker constructions wear their smoke-blackened insides with pride. It’s probably a bit girly to be caught buffing up your smoker. The wooden interior also adopts a beautiful honey colour after a few firings.
I am reliably told that the glue used in untreated ply is PVA and won’t emit toxins with a bit of heat. However it does have a low melting temp, and although I have seen no evidence whatsoever of this in my smoker, if it was a concern in any way, then make the inside out of something else.

Rebar supports act as locator for removable roof

Rebar in place for hanging food

Smoke chamber
Putting the 2.4 m x 1.2 m x 7 mm sheet of untreated ply over a treated one, I cut them into four equal pieces, 1200 mm x 600 mm less a saw width. I clamped them and trued up the cut edges with a plane. For one side, on a treated sheet I lay down lengths of untreated wood pieces, 24 mm x 40 mm, in a frame around the outside edge. Glue, clamp and screw in place, put in any woodblock fillets where holes are to be drilled through or for strength for attachments. Mark on the outside where they are. Add a thin layer of insulation and glue and screw the inner untreated sheet in place. Make another two sides exactly the same.
In the fourth side, cut a door out of the two sheets first before making it the same way. The hole for the door I made 410 mm x 750 mm, with the bottom lip 300 mm up from the edge of base. Keep the two off-cuts to make the door. This is the time to fit any metal sheathing on the inside of four prefabricated rigid sides if you want to.
On two opposing sides I glued on the 1200 mm x 40 mm x 40 mm tan corner posts with the inside faces flush so that the inside corner has only the untreated ply faces exposed. I drilled holes in the posts for the 65 mm x 12 g hex-head roofing screws. When the opposing sides with posts are finished, glue and screw all four sides together, making sure everything is square (I used a builder’s square and measured across the diagonals). After the glue is set, scrape off any glue beads.

Roof “ring” and inner roof

Outer roof prior to insulating. Note hole in end for damper pipe

Roof
I installed supports on either side of the top of the smoker box to locate the rebar which the food hangs on. A simple way to make these supports is to draw a line down the centre of a piece of 100 mm x 25 mm and drill 20 mm holes down this line at 100 mm centers. Run the piece lengthways through the table saw and you have two identical wooden supports with half rounds. Glue and screw these to the inside top of the smoke box with approx 20 mm protruding above the top of the box and this will locate the roof easily in the exact spot.
Next, I built a wooden square “ring” from lengths of untreated wood 70 mm x 50 mm and seated this square on the top of the smoke box with about 5 mm gap between the sides of this wooden square and the rebar supports. Lay bits of plastic bags under the mitred-and-glued joints or nothing will come apart when you want to disassemble it for moving. This is the base for the roof.
(In hindsight, a better approach for the inner roof would have been to use two ends of untreated 150 mm x 25 mm ply in a half-round shape or low arch and just fix galv sheet to it.) From this point, build the front and back face to the outer shell, insulate well and build the roof “at style” as they say in the boating world; any style is fine so long as it is insulated. Make sure you have about 130 mm height in the arch to take the flue which exits out the back.

Building base on upside-down smoker

Flue, damper
I built the flue out of a short length of 80 mm diameter downpipe and a bend and fixed it all on with a wooden bracket. I drilled 20 mm diameter holes in the pope for the spindle for the damper which is a piece of sheet steel. Into the damper spindle (a 20 mm-diameter wooden dowel, 150 mm long) I cut a thin slot 90 mm long down the centre to take the sheet steel baffle (a tin lid would do). This sheet was marked and cut to the inside diameter of the flue, but slightly oval and longer on the cross axis.
I assembled it all in the pipe and to hold the sheet in the dowel, drilled a locator hole and screwed through the side of the spindle and into the baffle itself
You would be amazed at the difference a movement of 2 mm with this arm makes to the temperature. Very simple and cheap but effective.

Damper

Base
With the smoke box upside down, I built onto it another square wooden “ring” of lengths of 70 mm x 50 mm timber to form the basis of the lower assembly. This square was a few mm smaller than the inside measurement of the smoker box
To this square I fixed the walls of the actual combustion box. These walls were 220 mm deep and protruded 20 mm down (or up when up the right way) into the smoke box to act as a locator. These completed sides were topped off with another square of 40 mm square wood lengths and onto this was glued and screwed the 15 mm thick plywood base. I made the base 1200 mm long by 690 mm wide so the two sides of the ‘ring were each actually 1200 mm long.
I turned the base up the right way and lined the combustion box with cement/fibre board. I cut the hole on the outside base to seat the gas bottle, made the handles or cross-braced frame for pulling the whole set-up on wheels, the box for attachments, the access flap and hole for the burner to go through the side wall of the combustion box—all ad-lib and kept me in the workshop for a bit longer. Now would be the time to fit the bar, TV, fridge, boat washing station etc, etc.

Fan exterior

Door
Now it is starting to look the business and getting very exciting. An internal architrave, glued and screwed into the door space in the smoke-box with 20 mm or so overlapping, provided a door stop and smoke seal…of sorts.
I cut a window slot in both inner and outer layers of the door ply and then framed up and glued in the framing for the door itself on the inner ply face. It needs plenty of wood-block internal supports for hinge screws etc so there’s not a lot of room for insulation in the door.
To make the door conform to the right shape in place, I laid it in place on the smoke box architrave, insulated it and then glued and screwed on the outer face. This method allows for the fact the door, once dried, is very rigid and you don’t want gaps.
Next I cut the glass with a 15 mm overlap. It was my first glass-cutting experience and you could have glazed the Crystal Palace with all the panes I destroyed in the attempt. Eventually, while standing in a mountain of glass shards, cut, bleeding and swearing profusely, I found a simple glass cutter in the tile kit I bought for the pizza oven and the light went on.
In an instant I was an expert and an insufferable know-all on the subject. I even cut a spare for the door. I sealed the inside glass to the door with sealer and architraves then did the same with the outside glass but without sealer…in case I wanted to remove the glass for cleaning. Fix the outside edges of the door with the architraves again, overlapping onto the outer skin of the smoke box to form another smoke seal...sort of.
Then it was time to screw on all the fun bits, latches, hinges, wheels and outriggers etc and drill holes for the temperature probes.
I bought a new single-ring, double-row burner at the nearest big barn retailer after nearly blowing my head off with a second-hand one (don’t try this at home guys…new is good and costs the same). Get a temperature probe that is accurate and good for tight temperature ranges. One digital probe goes into the salami sausage to continually monitor the internal meat temperatures without the need to open the door; another temperature probe is fixed through the door to monitor the smoke box and a third through the front wall.

Ventilated fan box

Fan
I retro-fitted an externally driven, electric fan from an old oven (with all wiring done properly by a friendly local sparky). I cut away an area 150 mm x 150 mm from the outer skin of the smoker to fit it. I located the motor spindle centre 350 mm down from the top of the smoker on the left-hand side. I then added a metal plate to the inside for extra motor insulation and, on the outside, a covering box with ventilation and a dimmer switch. Baffles on the inside, over and under the fan, direct the air sideways to boost heat-transfer speeds at the upper end of the range. There is a fan controller on it but this is not essential.
It was like adding a turbo-charger to it and you wouldn’t want to be without the fan when reaching for those higher internal meat temperatures. It takes hours off the process and all at the right end of the day. What took seven-hours plus without the fan now takes 4.5 hours…and that was with ambient winter temperatures around when I first tried it. Don’t leave home without it

Smoke generator
First I built my own smoke generator out of tin cans and pipe from a clip on You Tube. While it worked OK, it was hideous and made some of my other workmanship look quite good. It helped with testing but I made the decision to purchase one of the excellent stainless steel ones you see on Trade Me. It was the most expensive part of the kit by far, but if nothing else it adds a touch of class and technology to the build, and it works brilliantly too, producing volumes of smoke.
The whole exercise was a huge amount of fun and the basic apparatus was relatively cheap. You could make this as expensive as you like but I guess it cost me about $150 for the smoker materials including wood, glues, screws, hinges etc, $100 for burner (use the bottle and regulator off your BBQ), two small temperature gauges, second-hand oven fan, switch and air pump. I bought the electric mincer, sausage stuffer, motor assembly and fan blades, temp gauges, smoke generator etc all off Trade Me. This would be the absolute minimum spend, about $250 to $300, which is dirt cheap for what it produces.

Salami all ready to go

Making salami
A healthy salami is a joy to behold hanging from the shed rafters; the smell is indescribable. Your first batch will be like discovering the Higgs Boson without the cost. Salamis make a great gift to anyone that appreciates the taste and the effort. The final result is light-years ahead of the supermarket product and the cost is about a quarter of the deli product.
I buy the simple meat ingredients from the supermarket. Casings, powders (with the correct amount of sodium nitrite preservative), recipes and advice come from an excellent on-line supplier. The money I spent to buy all the gear off Trade Me, including the domestic electric mincer and sausage stuffer, I could have used to buy a lifetime supply of salamis for the entire street. But that isn’t the point is it? If we counted up what it cost to go for a fish in our boat (out of earshot of the missus, of course)...
I am a novice on the subject and a semi-retired real estate agent (humility and honesty is a challenge—weak grin) so I have no great measure of curing/smoking experience. But I found plenty of research material and good, colourful advice from those willing to share, especially if you are doing it wrong. My tastes in deli food are hot to the point of verging on nuclear and I spice my salamis with extra ingredients such as home-made chili sauce which is hot enough to power the national grid. I suggest you start simply with just the pre-packed salami mix containing the curing powder and spices plus the meat. At this stage I make my salamis in test-size 3 kg lots which makes nearly four big salamis (about $100 worth retail) but the smoker could take many more.

Recipe
PEPPERONI SALAMI

Be warned, my recipe is a hot number.

1.5 kg minced beef

1.5 kg minced pork

2 tbsp crushed garlic

2 tsp cayenne pepper

2 tsp chili powder

30 grams crushed black pepper 30 grams whole black pepper Pinch salt

Pre-made preserving salami mix Casings

METHOD

In the 3kg of meat you can vary the ratio of types of meat (use venison, for example) but want about 25 percent fat in the mix. Remove gristle and the pork skin.
Put the meat in a large bowl, add the pre-made preserving salami mix and other spices. Mix well with a little water to keep it moist but not wet. I use gloves and take some time to mix the meat thoroughly.
Push ingredients into a sausage stuffer and feed into long casings. Sit casings in the fridge overnight to start the cure. Heat or allow the salamis to come up to room temperature before putting them into the smoker.
Put one temperature probe through the smoker wall and into a salami. Light the burner and smoke generator, close the door carefully (the door draught may blow the flame out) and bring the smoker temperature up to 50 degrees °C.
Like any other pyromaniac’s toy, this is a device you cannot walk away from for long…ten minutes at the most. As with the pizza oven, you have to frequently adjust the flue baffle or flame or just keep an eye on things. Time to read a book…perhaps on extinguishing fires.
After the smoker has been two hours at 50 degrees °C — the heat for smoke penetration—switch on the fan for the cooking process, wind the smoker temperature up to 65 degrees °C and keep it there for half an hour. Then wind the smoker box temperature up to about 85 to 90 degrees °C but no more (at a higher temperature, smoke thins out and the fats inside melt). Keep the temperature there. The idea is to get the internal temperature of the salami up to 68 °C minimum.
To be sure to cook it properly throughout, it’s wise to actually get that internal temperature of the meat up to 72 degrees °C. You don’t need to keep holding it there for any time as the fan has ensured an even temperature during the heat build-up.
At 72 °C, immediately remove the salamis from the smoker and cool them down in cold water. From go to whoa, this smoking process takes a bit less than five hours, depending on the load in your smokehouse. After the salamis are cool, put them back in the fridge for a few days then hang in a cool airy place for at least three weeks and up to two months to age (yeah right). By all accounts a white or blue/green mould on salamis is perfectly normal and aids with the cure; just clean it off prior to consuming. It stops you from gnawing at them … well it works for me. There are bad moulds—if the salami is undercooked or contains not enough preservative, then you need to take real care. Do not touch anything that looks suspect.

Smoker becomes honeyed

Smoked and packed Kahawai fillets

Smoking fish
Before smoking fish, I brine them. When the smoker was first in action, it seemed fair to run a beginning test. What wasn’t fair was the fact that we had to do the unthinkable and buy fish from the supermarket. On the up-side it was the cheapest fishing trip I’ve ever had and quite a lot more productive than some of my mates’ best efforts. You know who you are.
For the test, I bought four average-sized, fresh Kahawai at about one kg each whole. These were de-scaled, and filleted with the skin left on. The heads and frames went into a stock pot. Soak fillets for six hours (you could leave for twice as long). Remove from brine, lightly wash in fresh water, then pat dry. Liberally sprinkle with lemon pepper and allow to dry overnight in the fridge. In the morning I rubbed cane sugar over the flesh and laid the fillets on a rack and all was placed in the smoker along with the salamis.
I opened the damper full for the first hour and the smoker was set at about 50 degrees °C with plenty of smoke. The next hour was set at 65 degrees °C with the damper 75 percent closed and the last hour was 85 degrees °C in the smoker and the internal fish temp brought up to 63 degrees °C before removing from the smoker.
I let them cool in the fridge but not before picking large strips of flesh off for instant gratification. The visual appearance and taste was stunning, tangy, a little salty, smokey and full of depth. It was even more amazing there was anything left to put in the fridge. After the fish cooled, I vacuum-packed two fillets at a time for giving away to friends. I have to say that if someone gave me a smoked fish pack like that for a pressie I would be well pleased.
For The Shed magazine article we also smoked a Hapuka the same way and the taste was beyond description … divine almost. This is so different from the usual hot-smoke ten-minute method, which admittedly is still very nice. Smoking fish is well worth the small effort and time spent and beats doing the lawns any day of the week.

Recipe
8 fillets of fish
4 litres water
1 cup plain salt
1 cup brown sugar bay leaves