This is why I can’t roast outside.
Normally we pull an extension cord through the window and do our roasting on the front porch. We don’t really have a choice since roasting coffee produces clouds of acrid smoke, which sets off fire alarms and leaves a stench in the house for days. The problem with this setup is, when the temperature drops below about 60 degrees Fahrenheit, the roaster never gets warm enough to roast the coffee.
In the past, I’ve used a small space heater to blow warm air on the popper while it’s running, but the combination of the popper and the heater blow out circuit breakers. Also, using the pop corn popper as it was originally designed can leave you with melted plastic.
The coffee roaster, a West Bend Poppery II capped with a one pint, narrow-mouth mason jar. The popper cost me about $15 on ebay, brand new, including shipping. I’ve roasted more than 20 batches in it over the last two years and haven’t had any problems.
Close up of the clip: a lightweight picture hanger attached to a spring which is attached to a short length of 18 gauge steel wire. The wire goes through a hole drilled in the top of the popper and then through a couple of washers to keep it from pulling out.
Roasting chamber, unhooked.
Close up of the jar. I scored it once around with a glass cutting tool, heated the scored line over a candle, and then dipped the jar in a bowl of cold water. After that I used a normal sanding drum bit on a Dremel tool to smooth the edges of the cut glass. The irregular crack on the near side is where I failed to get the jar hot enough to crack on the first try.
When done properly, the score-heat-quench method can cut a straight line around a bottle (or jar).
The pre-roast weigh in. The coffee I’m using is Mexico Fair Trade Organic Oaxaca Water Process Decaf from Sweet Maria’s. It’s dark to start with because it’s decaf, 100g is about all my roaster can handle.
Into the roasting chamber you go, my dears.
A view of the whole rig. The board is just shorter than the width of the window frame, which leaves a little room at the far right for ventilation (in addition to the space around the chimney).
The chimney is about three linear feet of 3” diameter steel ducting. Where it meets the top of the roaster, I cut a fringe in the end of the pipe and flared it out slightly. There’s not a tight enough seal where the chimney hits the jar, so I wrapped it in aluminum foil. Air is drawn in around the pipe where it pierces the MDF, and is heated by the pipe, which gets way too hot to touch by the time the 7 to 8 min roast cycle is finished.
The chimney blows the chaff out into the garden. It’s, like, totally ecological, or something.
I use a flashlight to keep an eye on the color of the beans while they’re roasting. In this case, I hit first crack at about four minutes, and finished at just over seven. Decaf roasts faster than regular and produces less chaff, in case you were wondering.
Just finished (the roaster is unplugged), checking to make sure the color is good.
This thing is friggin’ hot when it’s done.
Onto the cooling tray, a medium sized (about 12” diameter) pizza pan.
Tada! I left it outside on the porch railing for about five minutes to make sure it cooled off as quickly as possible.
And the finished product. You can see the volume of the beans has increased, but the weight has decreased (100 grams down to 87 grams). I pretty consistently lose 15% of the pre-roast weight. That means if I pay $5.00/lb ($11.02/kg) for green beens, it’s actually costing me about $5.88/lb ($12.96/kg) for roasted coffee.
Still a great deal since Zeke’s charges $9.99 a pound for the same coffee if you have them roast it for you.
Green to roasted in about 20 minutes (setup + roast + teardown). 100g starting weight leaves me with about 85g which we’ve found to be enough for two batches in the french press.
Without precise temperature control the quality varies, I’m sure, but I’ve only had one batch that wasn’t better than any store bought, pre-roasted coffee I’ve ever tasted. Coffee is best when roasted less than five days and ground less than five minutes before brewing. Bringing the roasting into our home means we get 98% better coffee than we can buy in any store. I’ll leave the extra 2% to the dedicated home roasters.