Roasting is a dirty job- no doubt about it. All day long I’m covered in dust from the green beans, burlap from the coffee bags, and coffee oils from handling the roasted beans. Personally I don’t mind. I was the kid always playing with the mud puddle or digging a hole in the backyard just to see how deep I could get. As a roaster, it’s important to balance this inherent mess with the cleanliness needed to produce a clean and safe cup of coffee for you. For myself this dictates a day of constant hand-washing and blowing dust off my clothes with compressed air. How does this affect the roaster itself? In order to keep everything clean and in working order, regular maintenance is required. Today, we’ll be talking a little about what that entails.
The roasting process leaves us with several byproducts. One of these is a creosote that builds up inside the roaster in different forms. In some places this creosote is a fine powder collecting on pipes and motors. In others, this creosote is a sticky, tarry substance that coats pipes and reduces their available volume. This tarry buildup can collect burlap or other flammable materials and is combustible itself. It’s important to control this buildup to minimize fire danger as well as maintain consistent roaster performance. To this end, the roasting team here at Portland Roasting adheres to a regular maintenance schedule ensuring that both roasters remain clean and fully functional. This week, we’re doing maintenance on the 60kg Toper (our smaller production roaster).
The first step is to disassemble much of the roaster so that we can get inside and clean out all the hidden parts. This includes removing the cooling fan, exhaust fan, exhaust piping, bean hopper (where the beans are stored before the roast) and the bean chute (which guides the beans from the hopper into the roasting drum). With these parts off, we can determine how much buildup exists and decide on our cleaning approach. On surfaces that do not come in contact with beans (such as fan blades) we use a cleaning solution that softens the creosote and allows us to remove it easily. This requires some soaking time, so we’ll apply the solution right after we remove these parts. As we’re soaking the fans we’ll focus on cleaning out some pipes. Singing a little “Chim Chim Cher-eeâ€, we use long-handled wire brushes to remove buildup from the insides of the exhaust pipes. Once these pipes are back down to the metal on the sides we’ll head back over to the fans and get to work cleaning off those blades. It’s also important to spend some time with the fan housings as buildup in the housing degrades performance just as much as buildup on the fan itself. This tends to be the dirtiest part of the maintenance and leaves us with piles of smelly, sticky residue. Thank goodness that part is over!
What a dirty fan!
Oh so clean!
With the fans and exhaust pipes done, it’s time to focus on the cooling tray. There are several aspects of the tray that need to be cleaned in different ways. Under the tray itself, dust and bits of broken beans collect and need to be removed either with a shop vac or lots of sweeping. Parts of the broken beans collect in the holes on the top of the cooling tray and these also need to be removed so we have a special pizza-cutter tool to accomplish this. Clearing out all of those tiny holes can be quite hypnotizing to say the least! Now that the dust and broken beans are dealt with, we’ll use a wire brush to remove any buildup from the top and sides of the cooling tray. Because this surface comes in contact with the beans, we only use alcohol or a natural-based cleaner.
Ewww! Also, fire hazard!
You could eat off of it! Please don't...
With the cooling tray finished, we’ll turn to the bean chute and spend awhile chipping away at the buildup inside. There is a sight glass in the chute and several spots for temperature probes, so caution is required while cleaning this. We’ll use scrapers and wire brushes to take the chute back down to bare metal. Then it’s onto the cyclone. The cyclone is part of the air quality system and plays a role in reducing particles and smoke being released into the air. It tends to get very dirty, and during maintenance one lucky roaster gets to climb inside the cyclone and use a pneumatic scraper to remove creosote from the walls. This is quite an interesting job, but not as claustrophobic as one might imagine. It’s a tight squeeze, but you can look up and see the sky (or get rained on, depending on your luck) so it’s not too bad.
The cyclone is the last major piece to be cleaned, and the rest of maintenance focuses on smaller (but equally important) aspects. These include blowing dust out of all the corners and crevices in the roaster, cleaning the air intake filter, blowing dust out of all the motors, cleaning the inside of the electronics cabinet, polishing the brass cowling on the roasting drum, and many, many hand washings. We’ll put everything back together, give it all one last wipe-down and then fire it up for a test run to make sure we replaced everything properly. And that, as they say, is that!
Regular maintenance is a must. A clean roaster is a safe roaster, and provides you with reliable and consistent performance. It’s worth it to spend a day up to my elbows in tar to know that when we need it the roaster will be performing at the most efficient and safest levels possible. Thanks for reading, and if you’d like to try out some maintenance yourself just shoot me an email. I’m sure we can find something for you to clean!
