DIY Venturi Cold Smoker

I wanted to cold smoke some malt with oak for a Grodziskie I'm making. After looking around the inter web, I decided to make my own venturi cold smoke generator. This is not a new idea, but I don't think anyone has posted a DIY here on how to do it.

The venturi smoke generator uses a metal jar in which wood chips are placed. A few wood chips are lit to produce a smolder. An aquarium pump is used to drive the smoke out a pipe into a smoker. Since the smoke generator is separate from the smoker, it produces a cold smoke. When you are smoking malt, you want a cold smoke so that you don't get roast characteristics in your grain, just the smoke flavor.

So for my project, I used an old SS cocktail shaker as the jar, a few pieces of 1/2" copper pipe and a few fittings to make the smoke generator.

The first thing I did was to drill a hole into the cap of the cocktail shaker and insert a 1/2" copper pipe to 1/2" MIP fitting. I used a 1/2" conduit nut to secure it in place:

Here is the cap on the cocktail shaker:

I drilled some 1/8" holes on the side of the shaker as a lighting hole. I drilled some holes on the bottom as air vents and I drilled holes and used some nuts as feet to hold the shaker off the ground:

Out of the top of the shaker lid I put a small length of 1/2" copper pipe. This went to a tee. In front of the tee was another length of 1/2" pipe that fit into another 1/2" pipe to 1/2" MIP adaptor.
On the back side to the tee was the venturi

The venturi was a length of 1/4" OD water line inside of a short length of 1/2" copper pipe. On the end of the copper pipe is a 1/2"MIP to 1/4" compression fitting. The 1/4" water line fits thru the compression fitting and its position inside the 1/2" pipe can be adjusted.





In order for the 1/4" pipe to fit thru the compression fitting, the inside of the compression fitting had to be drilled out with a 1/4" drill bit:





The length of the 1/4" tube is adjusted so that it sits just forward of the tee. An air supply is hooked into the end of the 1/4" pipe and air traveling out of the tube causes a venturi drawing smoke from the shaker thru the pipe

To attach the smoke generator to the smoker, a hole is drilled and a 1/2" MIP to 1/2" copper pipe adaptor is attached. Here it is on my UDS:



Wood chips are placed in the shaker. Here I am using oak chips:

The lid is placed on the shaker and the aquarium pump is hooked up:






The wood chips are lit using a torch aimed at the lighting holes in the side of the shaker:

Here I have taken the pipe out of the UDS so that you can see the smoke generated:

Grain is placed on a screen in the UDS. The grain is wetted with water to help capture the smoke:

Put the lid on the UDS, and in a couple of hours, smoked malt.

I love this idea. I am finally enjoying a smoked lager that I made back in November. I may have to try this for my next smoked beer. Thanks for sharing!!!

So the aquarium pump was not powerful enough to push smoke out of the UDS. I changed the aquarium pump to a nebulizer on a variable voltage control. A lot of smoke at the level of the grain now:

Here's a pic of the UDS.

Temp in the UDS at ambient temp

Pretty Cool.

This youtube video gives a great explanation on how to build a venturi cold smoker.

[ame]http://youtu.be/frSrfMjjC3M[/ame]

That's very slick. Do you think a smaller grain chamber with venting would draft well enough to use an aquarium pump?

I used a tailgating grill as a second chamber on top of a buddy's smoker with a few elbows. It worked fairly well as the temp stayed below 100 but the capacity is limited and there are 0 points for aesthetics on my solution.



I used a couple $1 stainless steel lint traps cut open and sewn on with stranded copper links to hold the grain. It took a jiffy pop looking tin foil ring to get 3lbs of malt to fit under the lid.



Were you able to get a couple hours of smoke with your cocktail shaker or did you have to reload?

That looks like a good build. Functionality always wins over aesthetics. The aquarium pump I got was not very powerful. You can get high flow pumps which I think could be powerful enough to fill a large chamber like an UDS. I had a nebulizer sitting around so I didn't want to go back and spend $30 for a larger pump. If I had used a smaller vertical smoker, the small aquarium pump would have been fine. The problem with the small pump and UDS is that all the smoke stayed at the bottom of the UDS. There is no heat, so no convection to pull the smoke up out of the UDS smoke stack. The nebulizer just barely running forced the smoke out of the UDS.

I ran the smoker with the aquarium pump for an hour and a half without refilling it. When I hooked up the nebulizer I refilled the shaker with chips and ran it for another hour. With the aquarium pump I could have easily run the smoker for two hours without refilling. Probably could have gotten close to that with the nebulizer.

The lesson I learned was to get a good sized aquarium pump if you are gonna fill up a large smoker.

BTW that was 8 lbs of wheat malt in the smoker

Cool thanks. Unfortunately it won't function very well once my buddy takes his smoker back. I'll probably reuse an existing aquarium pump and live with a smaller chamber to try a DIY venturi.

Are you brewing same day with the cold smoke malt? A lot of the home smoke malt posts say to wait but they're all pretty much higher temp BBQ rigs.

Right now the smoked malt is in a paper bag. I'm gonna wait a week before I use it. I've heard that's it's better to let it mellow out a bit. The malt smells fantastic and tasted great. Hoping it'll make a great beer.

I made a Grodziskie last week with 1/2 wheat malt and 1/2 store bought beach wood smoked 2 row. Gonna compare these two when they're done.

I took it a bit further and hooked to smoke generator (cocktail shaker soldered to a stainless tee) to a medium size electric oven.
works pretty good , some technical problems on the first use but the final product (turkey breast ,chicken and goose legs) was excellent.

cheese said:

I took it a bit further and hooked to smoke generator (cocktail shaker soldered to a stainless tee) to a medium size electric oven.
works pretty good , some technical problems on the first use but the final product (turkey breast ,chicken and goose legs) was excellent.

Click to expand...

That is excellent. Did you cook the meat in the toaster oven while you smoked? or was the toaster oven just used as a smoke chamber?

geniz said:

That is excellent. Did you cook the meat in the toaster oven while you smoked? or was the toaster oven just used as a smoke chamber?

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It was cooked and smoked at the same time.
Built in temperature control makes it so much easier to operate compare to wood smokers.

Does anyone have an actual parts list for making one with a cocktail shaker? That I could actually walk into the plumbing section of HD with a list a pick up all the connectors for making one? have been looking online at various design, and all of them seem to be thrown together with parts folks have on hand, or put together by folks with a knowledge of various plumbing and gas fittings....but noone took the time to write up a simple list of what's needed to build this thing. Anyone made one like the OP's that could actually put a list of fittings and couplers together?

Whenever I'm putting together a tutorial, or a recipe, I make sure to provide even the most rudimentary of parts, or ingredients, realizing that not everyone might have a working knowledge of x, y, or z, but STILL might want to build or make whatever it is.....

I'm attempting to build this this week. How did you connect the half-inch copper pipe to the 1/2"MIP to 1/4" compression fitting?

The 1/2" pipe fits inside the 1/2"MIP portion of the compression fitting. See pic on post number 6.
Its just a dry fit. I didn't solder anything on this project.
Hope this helps.

Very cool. I need to make one of these, I want to cold smoke some cheeses.

geniz said:

So the aquarium pump was not powerful enough to push smoke out of the UDS. I changed the aquarium pump to a nebulizer on a variable voltage control. A lot of smoke at the level of the grain now:

Click to expand...

Using a nebulizer for a smoker - somewhere an RT is is howling....

Built mine today and tested it before soldering the joints. I had to use foil to make the connections tight while testing.

https://flic.kr/p/qo3jZd

Very nice.
Just used my original the other day to cherry smoke some 2 row for a smoked porter.

A few thoughts about smoking food:

1. A great cold smoke generator is a brand new cheapo soldering iron stuck through the side of the chip container (I just use a coffee can). Make sure your smoking dust or chips contacts the iron and plug in the iron. I use this rig for cheeses and fish all of the time.
   
2. Billowing white smoke is less than optimal; it can deposit creosote onto your food. Thin, blue smoke is the goal. If you can smell smoke, you're smoking.
   
3. Don't use galvanized anything on food smokers as those parts may release toxins into the food.

geniz said:

Very nice.
Just used my original the other day to cherry smoke some 2 row for a smoked porter.

Click to expand...

Do you notice a difference between your smoked malt and store bought smoked malt? Is yours more intense? How long do you wait to brew with it after smoking?

adiochiro3 said:

A few thoughts about smoking food:

1. A great cold smoke generator is a brand new cheapo soldering iron stuck through the side of the chip container (I just use a coffee can). Make sure your smoking dust or chips contacts the iron and plug in the iron. I use this rig for cheeses and fish all of the time.
   
2. Billowing white smoke is less than optimal; it can deposit creosote onto your food. Thin, blue smoke is the goal. If you can smell smoke, you're smoking.
   
3. Don't use galvanized anything on food smokers as those parts may release toxins into the food.

Click to expand...

The only thing i would worry about being galvanized are the screws I used for the base. Do you think the aluminum foil is ok to leave in a few places (shaker cap has foil filling the gap created when I removed the original rubber cap that lined the SS cap)?

KLAAYHAUS said:

Do you notice a difference between your smoked malt and store bought smoked malt? Is yours more intense? How long do you wait to brew with it after smoking?

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I typically smoke my malt for an hour. I then put it in a paper bag to age for about a week before I use it. I've compared by oak smoked wheat to the Wyermann oak smoked wheat and mine has a more intense smokiness in the finished beer

geniz said:

I typically smoke my malt for an hour. I then put it in a paper bag to age for about a week before I use it. I've compared by oak smoked wheat to the Wyermann oak smoked wheat and mine has a more intense smokiness in the finished beer

Click to expand...

Gotcha, thanks!