Keep It Clean

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By Annelise Kelly

Commercial roasting equipment is not only a significant investment for anyone in the business, it’s the central tool for the craft. When your livelihood depends on roasting hundreds or thousands of pounds of coffee to exacting standards, properly maintaining your roaster is essential. By cleaning your equipment correctly, you ensure a consistent product; resist premature wear; minimize costly downtime, and reduce the risk of fire.

STiR talked to three experts for their perspectives on why it’s crucial to practice a regular and frequent cleaning protocol for the benefit of the beans, the machines, and the bottom line. Rob Hoos is director of coffee at Nossa Familia Coffee in Portland, Oregon, and former chair of the education committee of the Specialty Coffee Association (SCA). Michael Whitley is president of Alliance Service Network, which provides roaster installation and maintenance services in North America including Alaska and Hawaii. He founded the business in 2010 after eight years as general manager at Diedrich Roasters. Paul Thornton spent three decades at Coffee Bean International where he managed roasting and buying. Two years ago, he launched Thornton Family Coffee Roasters in Beaverton, Oregon, where he is director of coffee. Thornton spent the last decade serving SCA as president, board member, and chairman of the board.

Maintaining quality

A roasting profile depends on the dynamic interplay between heat and airflow. Consistent product depends on consistent roasting times and consistent temperatures, says Hoos.

Whitley elaborates, “You’re using different heat mediums to roast the coffee. Convective heat, which is hot air; radiant heat, which comes both from the burner and from the product as it begins to absorb the temperature; and conductive heat, from the hot metal in the roaster.” As the roasting proceeds, flakes of chaff released from the bean build up in the chaff compartment, affecting the airflow in the roaster.

“The convective heat of the airflow is the primary heat source. About 70% of the heat medium is from hot air. As chaff builds up, it inhibits the airflow, so that affects the heat of the roaster, which affects how the coffee is cooked. That’s why periodic maintenance is so important,” says Whitley. “It affects the quality of the coffee because suddenly your ratio, your mix between the three heat mediums, changes from less hot air to more convective heat, so now you’re actually using a different roast profile. You’re trying to duplicate the same result in a different environment.” Thornton points out, “when residue starts building up, your piping becomes a different size, in essence. In order to maintain the roast profiles you need it to be clean.”

Further, poor cleaning will negatively impact the cooling process, says Whitley. “Targeted cooling times range from three to four minutes. What we often see in the field is that the screens in the cooling bins aren’t cleaned often enough, so the holes plug with residue. Without daily maintenance on both the top and the bottom of the screen, the cooling process actually slows down which means the roasting process extends,” further disrupting the roasting profile. He advises roasters to clean the screen on both sides after about every four hours of roasting using a cooling bin roller or by pressing a wire brush into the holes.

Fire safety

Regular cleaning is vital to diminish the risk of fire. Built-up residue presents a risk. “It can take a while to light, but once it lights it’s like a grease fire,” says Hoos. He notes that buildup varies. “When you are roasting dark or roasting a lot of volume through a small machine, then you’re going to see buildup a lot faster. If you tend to roast lighter—we’re talking pre-second crack―then you’re going to see less buildup and have to clean less frequently.” When onboarding a new roaster, Hoos recommends you “check fans and ventilation monthly until you figure out exactly how quickly it builds up.".

"You might find out you have to do a deep cleaning on the pipes every six months or every quarter, or as we figured out a couple years ago, we didn’t have to do it more than every other year because we were roasting lightly and we had really good ventilation, so it didn’t build up.”

Thornton compares a roaster to a wood stove, with a similar risk of a chimney fire, and reminds roasters that “it’s kind of hard to catch on fire but it’s really hard to put out. You have a lot of airflow running through coffee roasters, which will stimulate the fire if one starts.”

Preserving costly equipment

Proper cleaning and maintenance are essential to keep equipment functioning optimally. Reduced airflow forces the machine to work harder, aging it prematurely. “Fans that are sucking smoke also get buildup on them, which can put them out of balance and cause exhaust issues and ruin equipment,” says Thornton. “If you do start a fire, you’re facing the cost of replacing expensive equipment. Having someone come out and refit pipes is also expensive, but the most expensive thing is you can’t roast coffee on a broken machine, and the last thing you want is to start telling customers that you’re missing deadlines,” said Thornton.

Whitley observes that “as a service and maintenance company, we see that the biggest cause of equipment breakdown is lack of maintenance.” Ensure you’re maximizing production and profitability by adhering to a regimen of cleaning, lubrication, and maintenance. Ask the manufacturer for their recommended protocol. Thornton suggests inquiring which small parts commonly break down, so you can keep them on hand. “A little relay motor or a breaker that costs three dollars can shut a roaster down: your worst scenario is having ten people waiting to package, then paying them to do nothing.”

Make sure to adjust your cleaning schedule when your production increases or conditions change. Humidity and darker roasts increase buildup rates, warns Whitley.

Observe a protocol

“So from a maintenance standpoint, there’s a schedule that every roastery should have,” says Whitley. “That includes checking things midday, going through a daily cleaning process, and a weekly process, and approximately every 40 hours of roasting it needs a pretty significant cleaning,” along with annual deep cleaning.

Follow the manufacturer’s guidelines and craft checklists specifying what tasks must be performed at four-hour intervals, daily, weekly, monthly, quarterly, and annually. Train staff to prioritize cleaning and maintenance and to document cleaning activities. When production soars, don’t cut corners: cleaning and maintenance are crucial to keeping your roaster humming, your product consistent, your employees productive, and your customers happy.