Tumbler for Cold-Smoking and Malting Grain

>> Sunday, April 22, 2018

Equipment time! I stumbled across this post on Reddit by u/Bearded_and_Bored a little while back. At the time, I was toying with the idea of brewing a Chicha-inspired beer but wanted to take advantage of malting the corn rather than doing the chew and spit thing. I also love smoked beers and was thinking this design would work great for cold smoking my own malt at home.

The design is fairly simple here; a standard food-grade bucket for the container, a simple box frame to mount everything to, a two casters connected to a rotisserie motor to turn the bucket, and a few more smaller casters to keep everything properly aligned. A picture (in this case a video) is worth a thousand words, so check out Bearded and Bored's Reddit post and related YouTube video for more info. Mine is essentially the same design as his, it's just made out of metal tubing rather than 2x4s.

I recently used this for the first time to cold smoke some California Select 2-row and it seemed to work really well. Here's the process I followed:

  1. Add grain to the bucket. For the trial run, I used 6 pounds of California Select Malt. You want the grain to be able to move freely, so don't pack it full.
  2. Moisten the grain with RO, distilled, our some other de-chlorinated water source at the rate of 9.5ml of water per pound of grain. The water helps the smoke flavor and aroma "stick" to the grain. 
  3. Fire up your cold smoke source and turn on the motor. Total smoking time on my first batch was about 2.5 hours. 
  4. After smoking, transfer the grain to a paper grocery bag and let it mellow for at least a couple days before brewing. 
For the first go, I used hickory. Hickory can be pretty assertive, but I'm using it in a smoked porter and I think it'll be able to stand up to the smoke flavor.

It's probably worth mentioning, for my cold smoke generator, I use a homemade aquarium pump venturi-style one. It works fairly well and puts out quite a bit of smoke. There are lots of options here though, Google cold smoke generators for ideas. Ideally you want something that isn't going to add any color to the grain due to temperature.

At some point I'll try using this new piece of equipment to malt some corn and possibly other grain, I'm also planning on smoking grain with some different wood varieties. More on that later.


Chomiczys┼éaw 6:04 AM  

Thank you very much for your post!
I'm planning to do the same project and I have a question about the motor you used. What's the model of the motor? What is its torque and wattage specification?
Probably I won't be able to find the same type, but maybe I'll find something similar.

MicroBus Brewery 2:13 PM  

Sorry for taking so long to reply. Somehow I missed the notification that a comment was on posted.
I bought it used off of eBay so I'm not 100% positive, but I believe it's a Brevel model 762. I can't seem to find specs for this motor, but generally speaking, it looks like most rotisserie motors are between 4-13 watts and can typically handle 30-40lbs of meat. Mine has had no problem dealing with 8-10-ish pounds of grain.