Filing Cabinet Food Smoker

Have you got a rusty old filing cabinet in the yard, or at the back of a shed or garage? Why not put it to good use?

I had smoked food on open fires and on improvised smoker frames, built over open fires, and I always loved the way even your tea water acquired a smoky flavour when boiled on an open fire. But I wanted something I could use at home and I set about designing my own for home use. A 5 gallon oil can was my first idea as we had made great use of large discarded metal containers, of all kinds, in the scouts in the making of ‘bank ovens’ and ‘mud ovens’. Great fun, and very effective. Cooking on open fires was compulsory in our scout troop and the annual week long scout camp allowed ample scope for experimentation (and disasters).
I wondered if anyone else was smoking food at home.

The internet was in its infancy at that time so research was mainly by word of mouth and somebody mentioned using a filing cabinet. I thought this was fantastic idea, not just because it sounded like it worked well, but also because it would create a spectacle, a humorous but practical talking piece. I did more research and mentioned the design to a good mate, a boat builder, who I knew had a filing cabinet he wanted rid of. He was easy to enthuse with interesting machines and gadgets and he loved his food as much as me, so 3 minutes after outlining my idea he found a lump of pipe which would be suitable for chimney, typically over engineered, but just the job. A hole was, without warning, cut in the back of the filing cabinet and the chimney attached.

“What do we do now Andy?”

“We could do with a test burn to see if it works.”

“How do we do that?”

“We need to light a barbeque charcoal in a tray in the bottom draw, cover it with mesh, and then make balls of oak sawdust or chippings with water, and put the balls on top of the mesh. But we don’t have any oak sawdust so we’ll have to leave it for a while, maybe tomorrow.”

“We can’t leave it now, I want to see if it works.

You find some mesh from the scrap pile and I’ll sort the oak. There’s some charcoal knocking about somewhere.”

Martin putting a piece of scrap old oak through the power planer to create fine shavings.

 

10 minutes later the charcoal was alight, and the first damp oak balls were on. Some old oven shelves were found and rested on some short lengths of small diameter mild steel bar to create the smoking shelves

 

3 drawer filing cabinet with old oven shelves resting on steel bars.

 

Not content with this Martin disappeared into the workshop and came back with the contents of his sandwiches and put them in the smoker. And then we stared at it for a while, with stupid grins on our faces.

The proud owners show off their newly finished, and lit, smoking cabinet.

 

So in the street outside the workshop, next to a filing cabinet, which, to passing motorists, appeared to be on fire, we ate the smoked fillings of Martins packed lunch, mainly cheese.

Our first test burn with the contents of sandwiches (we couldn’t wait), taste tested in completely hygienic conditions by the boat builders. “Ey it’s alright this!” – Martin’s business partner turns up and tucks in.

 

It was unanimously decided that we had a success on our hands and the next day we should have a proper ‘burn’, after a trip to the shops to obtain something other than second hand cheese slices. The filing cabinet was tilted onto a heavy duty sack truck and taken around into the back yard.

 

Day Two

Wet oak shavings on top of the hot mesh, in the bottom drawer

 

A selection of foods for cold smoking in the top drawer

 

As you can see it’s easy to make an effective food smoker from an old filing cabinet.

3 drawer cabinets are best as it gives different heat in each drawer, useful for different foods, but you can use a two or even single drawer, you will just have a little less flexibility.

The bottom drawer was heat and smoke generator, the middle drawer was for hot smoking e.g. sausages, and the top draw was for cold smoking, e.g. cheese. This was the theory but we discovered that even the top drawer became quite warm which was an advantage for some foods e.g. fish, but not for others e.g. Brie (which dropped through the bars).

You aren’t going to be able to do kippers, which take all night, but kippers were smoked for the purpose of preservation, for long-term storage, whereas we are talking about smoking just for the taste, and perhaps cooking at the same time. Cold smoking imparts flavour to foods which have already been cooked, and hot smoking can be used to cook and smoke at the same time.

It is fascinating to do experiments with different foods to produce unique flavours, and great gifts.

Below are the filing cabinet modifications you need to make:

 

1 – Chimney – You need to cut a hole somewhere near the top of the cabinet to let the smoke and heat out however, if you cut a hole actually on top of the cabinet then rain water will get into the filing cabinet, create a soggy mess, and accelerate its demise. Also a chimney added here may drop soot or tar onto the food. The best place is at the back or the side. Just a hole will do but an improvised chimney will keep the smoke out of your eyes, and will also look good.

Our chimney is at the back so rusty rain water can’t drip onto the food. My boat builder mate over-engineered the chimney (he over-engineers everything) but a simple hole will do if you don’t have a chimney.

 

2 – Shelves – Your food needs to be held above the filing cabinet drawer floors so the smoke can freely circulate around it. Our solution was to use some old shelves from a broken electric cooker, held up by thin steel rods pushed through the drawer sides.

Cheap cooling racks will do just as well and some designs of bought cooling rack can be stacked allowing you to smoke lots more food.

 

3 – Plastic bits – Modern filing cabinets have fancy plastic fittings like handles. The lower ones may need to be removed or they might melt.

 

And that’s the modifications done!

 

The cooking/smoking technique is simple:

 

1 – A disposable bar-b-q tray is lit and put in the bottom drawer.

Get the charcoal going in the bottom drawer

 

2 – Soak some oak chippings in a bucket of water.

 

3 – Once the charcoal is going strong you handfuls of wet oak chipping into balls, or a thick cake, can be placed on the bar-b-q mesh (which is normally used for cooking food on).

The oak will begin to smoke, and can be topped up at any time.

Damp oak chippings (pre-soaked) are placed on top of the mesh, which is above and resting on the hot charcoal.

 

The hottest part of the smoker is at the bottom and so sausages, for instance, would be better cooked (hot smoked) directly above the tray where the heat will cook them. You’ll need another piece of mesh for this, held high in the drawer so the sausages cook slowly. Alternatively leave them linked together and dangle and drape them inside the draw.

For cold smoking use the top drawer. Things like cheese and black pudding are best done here so that they smoke but don’t melt or re-cook.

‘Top draw’ experiments with a range of foods (cheeses, cod roe, fish, hard boiled eggs)

 

Things which are difficult to overcook, like vegetables, and things which are easy to cook, like fish, are best done in the middle drawer.

It’s not an exact science and cooking times will depend the local ambient air temperature, and on the quality of your charcoal. Some of the disposable trays burn quickly and hotly for a short period, and some bought charcoal burns painfully slowly. Something inbetween is ideal for most situations but a very slow burn is best for cold smoking.

Also consider the weather. A filing cabinet in the sun almost cooks food without additional heat so it is unreasonable to expect a cold smoke. The best time for cold smoking is in winter time, in the top drawer, on a cold frosty day, ideal for making Christmas presents of smoked cheese.

Cold winter days are good for cold smoking. Frost covered smoker and cold smoked vinegar cheese, hard boiled eggs, and black pudding.

 

 

Salting or Brining
Salting is important. Salt easily penetrates most foods and the chemicals within the wood smoke penetrate salted foods more easily.

“The smoke follows the salt” is the saying. Its some sort of chemical reaction/attraction apparently.

 

Cooked or Processed Foods
Cooked or processed foods (e.g. black pudding, cheese, etc.) can be placed straight into the smoker, without further preparation, as most processed foods already contain salt, but raw foods, may have to be salted.

A selection of cheeses can produce very different results even when cooked at the same time, side by side. Some cheeses will be subtly smoked and others will be strongly flavoured depending on salt content, and crumb texture (openness). You need to experiment to find which cheese suits your taste. I once did a selection of about five or six cheeses as Christmas presents. Everyone got the same selection but everyone had a different favourite depending on the level of smokiness, and on the combined flavours of the cheese and smoke.

 

Raw foods
All raw foods generally require salting or brining. Dry salting pulls the moisture out of food and soaking in brine will keep the food moist. The higher the salt content the more smoky the food will be however, you don’t want the taste of the food to be ruined by the salt, so you need to get your salting or brining times right.

 

Warming Cabinet
My filing cabinet was used annually as an effective warming cabinet on bonfire night, with spuds in the middle drawer and pies in the top.

The charcoal was lit in the tray as per normal but no oak shavings are added. The hot potatoes were put in the middle drawer, and hot pork pies were put in the top. It was a big hit with family and friends and people patiently queuing at the filing cabinet, and chatting was a lovely sight. Luckily the filing cabinet was modern enough to have an automatic locking device which prevented you from opening more than one drawer at a time, an anti-toppling device, otherwise we might possibly have buried several small enthusiastic children with hot pork pies.

 

 

Other experiments
We discovered that sometimes the cabinet got too hot and we found it difficult to cold smoke some things without them drying out. So we experimented (for hours) with smoke generators, a device for feeding smoke into the cabinet without the heat. Subtle changes to an ex-lavatory brush holder gradually extended the length of burn from 10 minutes (first attempt) to 45 minutes on a single charge. It was necessary to cut another hole in the cabinet, in the side. Here are some pictures:

Workbench smoke generator experiments. The welding mask is to prevent back draughts from a windy door, out of shot, to the right.

 

The cold smoker in action for the first time, feeding cold smoke into the cabinet.

 

It worked very well

 

Sadly the filing cabinet was the victim of several mishaps. My dad and Martin nearly destroyed it with an over enthusiastic use of accelerants one bonfire night, melting all the plastic handles and slightly warping two draws.

The following year gales blew it over with such force the impact deformed it slightly making the drawers even more difficult to open. And finally, on Boxing Day 2015, it was submerged beneath flood water, silt and sewage.

A new filing cabinet was required.

 

It’s a very worthwhile project if you like smoked food, and good fun.

 

Andrew

 

 

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