DIY Smokers Part 1 - A Cold Smoker in a Cardboard Box

OK...... so now that the nights are drawing in and the temps are starting to drop, it is the time of year to start some smoking. Its a fair while yet though before thoughts of Smoked Polish Sausages, Bacons, Gammons and other porky delights can be entertained.....my pigs are ordered for early December and mid February! I have been drying chiles and tomatos a lot over the summer...I just love sun dried cherry tomatos as a snack or to use in recipes....so I suppose I ought to start with that...but I won't...I will leave that for a few days, what we really need to get off to a flying start is some sought of smoker and a plan for next weekend!!

The most basic smoker you can probably come up with is a good old cardboard box...Ok it won't win any prizes in a craft show but one thing is for sure, it is more than capable of making a lot of cold and even some tasty hot smoked goodies!

The Cardboard Box Smoker

A smoker is after all just a chamber to allow smoke to flow over food. So long as we can provide some ventilation and keep the sawdust smouldering we can smoke food!

This may all sound a little foolhardy, after all smoke is eternally associated with flames and the idea brings to mind horrible scenarios involving barns and I don't want any lynchmobs at my door.... so a quick word of warning! Using such smokers should never be done indoors, infact smoking this way really obliges you to set up the smoker outdoors, well away from anything flammable and never when winds are to be expected! There is always going to be a small element of risk and the use of a smoker requires a regular presence throughout the session to check on and adjust temperatures, change the sawdust when it runs out and generally keep an eye on things.

With cold smoking there is little risk, the whole idea behind the technique being to keep temperatures as low and with as little difference to outside temps as possible. By heating the sawdust until it starts to smoke outside of the box on a small burner or over a fire, we have no need for a heat source in the box itself. The sawdust is introduced already smoldering, will do its job and simply just burn itself out. Cold smoking can be long process (from hours to days) and sawdust will inevitably need changing every hour or so, but don't worry, you do not need to lose any sleep, just let the smoke die down at night and light a new batch in the morning!

What you will need.........

 

A large cardboard box....the sort of thing a telly comes in would be admirable for the job but smaller boxes can also be used. Here I am using a box a speaker came in...any box that opens at the top is great for a smoker. When hot smoking though, a broader box, a seperated firebox and smoke chamber arrangement or a metal container is a much safer option.

2 dowel rods, canes or preferably steel rods...about 20 cm longer than the width of your box.

Metal grill ..one from a smallish BBQ or perhaps the shelf out of a cooker, would be ideal.

Sawdust container......old cast iron fry pans or small casseroles are great, but just about any fireproof metal recipient can be used.

Cover for the sawdust container......an aluminium pie tin or oven tray of the right size for your container, with plenty of holes pierced in it, to be placed upside down over the sawdust container. Although there is little chance of a great deal of dripping fat at low temperatures, this is essential kit for anything but true cold smoking. The cover makes it very difficult for a flame to get hold and stops any odd drips of fat from the food landing in the sawdust. Better still for hot smoking would be to have a drip tray positioned similarly to the food grill on two rods lower down in the smoker in addition to the cover.


Small sheet of metal or slab of stone.... to place in the bottom of the box ( the sawdust container sits on it).

External heat source.....can be a fire/gas burner/metal hot plate or an electrical element, if you have a proper housing for it, are all ideal for lighting your sawdust. Some people prefer to use a blowtorch to light up, but I find getting the whole container hot gets a better and more reliable smolder going. This does introduce a little heat into the smoker though, but not enough to cause any worries of overheating, so long as the ambient temperature is low and you have good airflow. Even with poor airflow the heat will dissipate into the metal/stone slab and should not cause any risk of setting light to the cardboard.


Sawdust can be had for free or next to nothing at your local sawmill, just go ask them if they have pure oak ....I paid 10€ for a cubic metre of fine oak sawdust last year....it will last me three years...LOL. The sawdust really must be a hard wood and include no resinous softwoods whatsoever, as they would give your foods a nasty resiny (inedible) flavour. Oak and beech are probably the best and easiest to get hold of over here but the fruit woods (apple, cheery, plum etc) make great smoking dusts too, if you can source them or make them yourself.

The huge advantage of sawdust over woodchips, or even shavings is that they are an awful lot more difficult to get it to hold a flame. This is exactly what we want in for safe smoking in a small space. If we were to setup an offset firebox, or have a firepit at the end of a tunnel or pipe leading to a seperate smoking area, then we could happily use chips or solid woods for smoking. For this sort of smoker I would highly recommend only using fine sawdusts.

Building the smoker.....

The box I built today is really for cold smoking only. It was made from one of two speaker boxes that have been knocking around in the cellar for a couple of years now. Whilst being too narrow to really want to risk introduing a heat source, apart from perhaps a very small gas burner or hotplate (not a camping gas type burner though as they are way too unstable) these boxes can make a great multi level cold smoker!


I started off at the top of the box, to make the grill levels for the food to be smoked. This is really simple, just poke a couple of holes through opposite walls on each side of the box. Make them about 20 cm from the top. Then cut two bits of dowel/bamboo to about 20 cm longer than the distance between the two pierced walls. These two rods will support the grill...or if you have a box like mine, then you can always add more levels, if you have enough grills! With this box I made two sets of holes for a double decker cooking area in the top half of the box and then added another set of holes about 3/4s of the way down the box to make a shelf for a drip tray.

In the above picture you can see the double decker effect. I actually cut enough holes to make it a four level affair if needs be. You could easily smoke a good couple of dozen duck breasts at once in there!


Moving down to the bottom of the box, we need to have some sort of easy access to change the sawdust and to keep an eye on things. Again a easy task..just cut a trap door with a knife, so that it opens at the bottom of the box (can be pulled down to floor level). I cut a door in both sides of the box, which can be useful to allow for a better airflow inside the box or so that you can change openings if the wind turns!

Once the trap doors are cut, we can start kitting out the base of the box. Its a pretty good idea to insulate the base a little, even if we are only cold smoking the sawdust container can get pretty hot. I had a few small tiles handy, so I lined the base of the box with them. You could equally use a bit of paving slab, a metal plate or the like. Something heavy in the bottom of the smoker is never a bad thing in any case, as it helps to keep it stable and may keep the smoker upright if an unsuspected gust of wind arrives on the scene.

Now it just remains to fill the tray with sawdust, get it lit and place it in the smoker. Don't forget that old pie mould or alu oven tray though. You will need to pierce with a generous amount of holes first, to let air through and smoke out. Placed upside down over the sawdust tray (as you can see above) no flames will be able to develop.

Other nice bits to have

Fans are handy to keep things smoldering nicely... There are a few cheapo options available here too...you could use a desk type fan outside the box, with the door open, to waft the smoke around inside the box and improve air flow. Or try placing a small hand held fan or minature desk fan inside the box..just cut another hole for the cable or simply pass it through a trap door. The enterprising may get great results by cutting an extra hole in the base of the box and installing an old 12v computer fan (the ones on powersupplies) to generate flow or to turn a hot smoker into a convection smoker! Put it on a transformer and you can adjust the air flow at will too.

Thermometers... Very much an essential tool for controlling temperature of hot smoked foods. The best setup would be to have two, one in the food and one inside the box...I use just one most of the time, both to monitor the heat in the box during the smoking (pierce the side wall with its pointy end and hang off one of the dowels) and to check on doneness. For cold smoking it is nice to have one about to check that the box isn't getting too hot, but is by no means essential.

So thats the smoker ready for some food and a good ol smoke out!! That will not be until next weekend however, when I will put it through its paces with some cold smoked duck breasts. Watch out for the recipe tomorrow....................................

All the best

Guy