Home building a commercial style roaster (two year update)

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
perfectwheels
Posts: 208
Joined: 11 years ago

#1: Post by perfectwheels »

200+ roasts later...
Some may remember this roaster building thread from a couple of years ago. Home building a commercial style roaster I wanted to post an update covering flaws in the original build and the fixes I have come up with.

Here is the roaster in its current state. The obvious changes seen here are the bean hopper that can now hold a 5 pound charge and a redesigned cyclone.




The first addition was thermal couples and a phidget so I could profile using artisan on my laptop. The original temp gauge only gave ET and wasn't very accurate it turns out (off by about a 100 degrees Fahrenheit).




The original cyclone had the fan in front of chaff collection which led to the squirrel cage getting clogged. This can still happen but only if I forget to remove chaff after 4 or more roasts. Normally chaff gets vacuumed out every other roast. I also changed the venting so the roaster is completely separate from the cooling system. This makes turn around time much faster... When I'm in the groove 4 roasts per hour are very doable.




It turns out the bushing system was a flawed design. There wasn't a good way to keep grease inside so there was a lot of annoying screeching sounds which would then require partial disassembly for addition of grease. The solution was the adding bearings and using high temp food grade grease. Simple pillow blocks were turned on the lathe from aluminum flat stock.

The original roaster was built without any machining tools but in the meantime I have acquired a 1930's Southbend lathe which is super useful.




Insulation
While it was great for heating the shop space, the lack of insulation was problematic. There just wasn't enough power to roast five pounds of greens... three and a half was kind of the sweet spot.




I built a shroud system for holding insulation on top of the roaster and then boxes for the sides. This has made a huge difference in the roasting capacity. Now it easily roasts a five pound charge and seems less influenced by ambient air temperature.




The addition of gas pressure gauge is also huge. Why I waited over two years to do this? Before I was just guessing heat by watching the flame, with this addition the heat is quantified, making repeatability of profiles much more accurate.




Adding a pilot light was another big improvement.




A lot of fitting work was recently done where the front of the drum meets the face but I still lose a few from the back. Next time that thing is torn apart I should replace the mesh with something finer.




The wiring is finally cleaned up with all the connections in a nice safe metal box.




Super fast profile of some Peruvian beans to FC+



So, as a wrap-up... I would say that while the original roaster was a success in that it worked to actually roast coffee, it has taken these improvements to get it to the point where one can consistently roast on a small scale commercial level. I am currently roasting 15 to 20 pounds per week and would be happy up to a 100lbs. If I get up to 200lbs per week then I'll be building a bigger roaster :).

moreshots
Posts: 134
Joined: 13 years ago

#2: Post by moreshots »

Nice job
We had much the same idea
I built mine almost 6 years ago and it works great

Here is a link
http://www.youtube.com/watch?v=uECZ_4oBPPg

The swwet spot in this one is 6 pounds winter 7 pounds summer

I'm considering making a 15 kg
18" pipe 24" long would be the drum

This one is infrared heat
Bill

perfectwheels (original poster)
Posts: 208
Joined: 11 years ago

#3: Post by perfectwheels (original poster) »

Bill, that is a nice looking roaster!

moreshots
Posts: 134
Joined: 13 years ago

#4: Post by moreshots »

she is a Frankenstein

But it works!!!!

edschlukebir
Posts: 102
Joined: 10 years ago

#5: Post by edschlukebir »

That is very cool. I've been researching roasters, and trying to piece together info, parts, and friends with metalworking skills to build a smaller version.

You seem happy with the straight sided chaff collector? Did you have to do anything to the inside or does it work similar to the more cone shaped ones?

perfectwheels (original poster)
Posts: 208
Joined: 11 years ago

#6: Post by perfectwheels (original poster) »

Internally there is a cone, so in function it is much like the original with a much larger area for chaff collection. I did experiment with straight sides but it didn't work as well so a cone was added.

moreshots
Posts: 134
Joined: 13 years ago

#7: Post by moreshots »

If you decide to move forward with your build, just consider mods will be a fact not a possibility.
While I like my build and it has been working great for 6 years I have a little st of changes to make

Insulate the bearings from the end plates to run cooler
Install larger mixing blades in the drum
Install a much larger blower for combined chaff separation and bean cooling

You will be rewarded every time you use it


edschlukebir wrote:That is very cool. I've been researching roasters, and trying to piece together info, parts, and friends with metalworking skills to build a smaller version.

You seem happy with the straight sided chaff collector? Did you have to do anything to the inside or does it work similar to the more cone shaped ones?