Roaster Cleaning: Exhaust Fan and Impeller

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It’s time for our quarterly maintenance at Mill City Roasters! If you’re on a similar schedule, you may want to start thinking about diving into your exhaust fan and venting to make sure they’re clean before the holiday season is in full swing. If you do not have a maintenance schedule, there’s no better time to start than now!

We clean the exhaust fan on our MCR-20 once each quarter because, based on our production roasting schedule on that machine, that’s when the coffee residue becomes built up enough to necessitate a scrub down. We are only roasting around 500lbs per week on this roaster, if you are roasting more or less than that your cleaning schedule will look different.

The exhaust venting and fan are just one of many points in your machine that should be well-taken care of to ensure smooth operation. Not only does this fan pull air through the system, it pulls smoke, chaff, and heat through to ensure our coffee is clean and tasty out of the drum.

Above you’ll see us tackling the exhaust fan on the 20kg roaster. On our 3kg machines and larger the process of removing and cleaning your fan will look similar to this.

After removing our fan cover we see a thin dark layer across the entire fan, and then lighter softer buildup around the impellers. If left long enough this softer buildup will turn into harder sediment that will reduce airflow further and require a lot more work getting it cleaned off.

We need to get the impeller off of the shaft, and it can be on there pretty tight. Remove the screw that’s holding it on there, and there should be a washer underneath the screw as well. After this, a Gear Puller can be a useful tool to pull the impeller off with ease.

Once our impeller is free, the cleaning begins! Use a burlap bag or large sheet of cardboard to catch any sediment, grab your KN/N95 mask to protect your lungs, and grab your vacuum to get any soft buildup off before scraping or scrubbing. No need to kick more sediment into the air than we have to.

Depending on the buildup, you have a couple of options for cleaning the fan. Using metal bristle brushes and paint scrapers can be effective and requires elbow grease, but good for getting into tight spots. Using a drill with metal bristle attachments grinds the buildup off but creates a mess of dust and sediment all around you.

Using Urnex Roaster Sprayz can be great to start breaking down the build-up and make the soft stuff come off with ease. Roaster Sprayz is made by the same company that makes Cafiza, the amazing cleaner baristas rely on to keep their brewing equipment clean and residue-free.

In the world of cleaning your roaster there is no right tool, just some that work better than others. My recommendation is to try out a handful of tools and methods and decide what works best for you in your cleaning schedule. Remember that maintaining a cleaning schedule will ensure your operations run smoothly, your coffee tastes great, and you avoid the fire hazards of your buildup in the venting.

Until next time, happy roasting!


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