Copyright 2002. All rights reserved.
Large roaster for homeroasting.
As a home coffee roaster, I have been frustrated by the tiny batch sizes of most home coffee roasters. To this day, there are only a couple of roasters for home use that roast more than a few ounces of beans at a time. For years, I've used the Melitta Aromaroast (3 oz. at a time), the Hearthware Precision (again, 3 oz. batches) and even the Hearthware Gourmet (3 oz. batches). This summer, I built the BBQ Grill roaster , and I have been incredibly pleased that I can get great, one-pound roasts. In some ways, this is the reason I have procrastinated in finishing this air roaster project. Until I started enjoying the fantastic roasts I've been getting on the BBQ Grill roaster, I thought a larger batch air roaster was the only way to go. I hope that when I finish this project that I am not disappointed in the roast quality as compared to the much simpler, and cheaper BBQ Grill roaster.
There will be a complete article and more photos in the future, but I was anxious to get something up here so I can explain a bit better what I am doing. This has been a very intensive project, and I would not recommend it to anyone unless you have a shop full of metalworking tools and deep pockets. Two of the parts for the heat chamber I had fabricated, at a cost of over $350. I lucked into some perforated stainless steel which I snagged at $20 for a 12" x 24" sheet. I also was given some stainless steel scrap from a fabricating shop which has come in very handy.
(Click the pictures to enlarge)
Here's how the air roaster heat chamber looks right now. It's about 14" in diameter and the sides of the chamber are 12" tall. I still have to fabricate a cone top on it with a 6" opening in the center where the roast chamber connects.
Air roaster heat chamber from the back.
Here's how the inside of the heat chamber looks. The burner is inside a 1/8" thick stainless steel heat tube. That keeps the flame away from the air flow as it spirals around the heat tube and channels the heat up and out. The sides of the heat chamber are cool to the touch because the airflow carries the heat away before it hits the outer wall.
When the fan and burner are on, it looks and sounds like a blast furnace. Lots of heat pumping out the top.
A 365CFM Fasco blower provides the airflow. The air spirals around the heat tube, and joins the heated air near the roast chamber.
A remote manual control can vary the air/gas mix. It's important that the heat chamber be airtight, so as to not lose static air pressure necessary to loft the beans.
The roast chamber still needs a lot of work. What you see here is where I've made the stainless steel cylinder and cut the oval perforated stainless for the roast floor. The perforations are about 1/8" holes. I intend to block off about a third of the perforations, from the top down so I can achieve a rotational bean agitation pattern as they blow up and then slide down the ramp back into the airflow. I will use 18 gauge stainless sheet placed over part of the perforated stainless to achieve that. I want to be able to have the option of varying the size of the opening to see what works the best when the roaster is ready for beans.
A $50 pop rivet tool is allthat's needed to securely fasten parts together with stainless pop rivets. Some have told me the cheaper pop rivet guns will work with stainless rivets, but those stainless buggers are tough to shoot even with the big tool.
The Homeroaster™ is dedicated to helping the coffee homeroaster explore, find, acquire, roast and brew coffee to achieve the ultimate coffee experience. If you have suggestions for articles or information concerning homeroasting, please send them to me. Great things are coming in the near future for homeroasting, and I am excited about the possibilities! Please check back soon for great homeroasting information and opportunities for coffee homeroasters!
Quote of the day..."Money can't buy happiness, but poverty won't buy anything"
Ed Needham 2002