Building a Drum Home Coffee Roaster

So you are going to build your own drum coffee roaster? You're nuts, but you already know that... and in fact a drum roaster is a very simple machine. Hey, if this guy on the right can do it, why can't you?

Also see our pictures of the Jabez Burns Sample Roaster

Perforated Sheet Metals Used in Home Coffee Roasters

Here's some information to those interested in building their own home coffee roasters, especially drum type roasters to be installed in gas Barbeque grills, what hole-sizes and patterns are used in the currently available coffee roasting appliances. Here are some images, and all should be at the same scale, although they are not "actual size":

1. The Alpenrost Drum is unique among these samples: it is the only one desiged to allow chaff to fall through it while roasting! Notice the percent of open space to metal ... this is highly perforated. The holes measure just a hair over 3/16 inch. It corresponds somewhat to McNichols 3/16", 1/4" staggered centers, 18 holes PSI, 50% open area (although it looks even more open than this, more like samples with 60-65% open area)

2. The bottom of the Hearthware Precision Roast Chamber has 2 hole sizes. The smaller hole is 5/32 " and the larger is 3/16, same as the Alpenrost. This is a little suprising since the function of of this roast chamber is not to allow chaff to pass down through the roast chamber and fall down into the base. But with such a positive air flow upward, this is not much of a risk.

3. This is the ring from the interior of a well-used Hearthware Precision Chaff Collector. This hols size and pattern is identical to the Zach & Dani's coffee roaster's roast chamber bottom, but I couldn't get a good photo of that. The function here would be to hold back chaff, but allow air flow. It is approximately 1/16" holes and corresponds to McNichols 1/16", 7/64" staggered centers, 98 holes PSI, 30% open area

4. This is an image of the Coffee Kinetics 1 Lb roaster's roast chamber bottom. This roast chamber is like any of the smaller air roaster chambers (Freshroast, etc) in that a strong air flow comes up from the base ... so the function is to hold the coffee and resist letting chaff drop down (although air flow prevents this too). These are 1/8" holes and corresponds to McNichols 1/8", 3/16" staggered centers, 33 holes PSI, 40% open area

5. This is the Freshroast roast chamber bottom, and they appear to be 5/32" holes with a much greater open area than the Coffee Kinetics (But the CK roast chamber diameter is about 8-9" compared to about 3" on the tiny Freshroast). This material corresponds with McNichols 5/32", 3/16" staggered centers, 33 holes PSI, 63% open area

6. This is not perforated metal, it is a screen, and its from the top of the coffee kinetics. All manufacturers are using screen for places where they want air to pass, but all chaff to be trapped. Freshroast Plus has the coarsest screen, HWP is very fine, and the Zach & Dani's, in the top piece, has an extremely fine screen.

I hope this helps a bit! Happy roaster building, and remember to visit the best BBQ roaster construction sites:

-Tom 2/14/03


The Complete Sweet Maria's Coffee Library Page
- Coffee Travel Pictorials, New Product Reviews, Roasting Pictorials, and more

 

Green Coffee Beans 70+ Selections Hearthware I-Roast 2 Fresh Roast Home Coffee Roasters - Two Models Gene Caffe Drum Roaster
Behmor 1600 HotTop Drum Roaster Stovetop Popper Roasting Espresso Equipment & Accessories
Nesco Home Coffee Roaster Technivorm Electric Brewers Chemex Coffee Brewers Coffee Bags: for green and roasted
Zassenhaus Hand-Crank Mills Nissan & Zojirushi Travel Cups/ Bottles Vacuum Brewers: Cona, Yama Coffee Cleaning Supplies
Espresso Machines: Giotto Professional and Premium, Rancilio Silvia, Andreja Premium , Gaggia, Coffee Books
Miscellany and Sweet Maria's T-Shirts
Electric Coffee Mills: Mazzer Mini, Maestro, Rancilio Rocky, Bodum Manual Drip Brewing
Our Roasted Coffee French Press Coffee Brewing Ibrik: Turkish Coffee Brewing Mokapot: Stovetop Espresso