I learnt that when the manual mentioned cleaning the chaff collector periodically with soap and water- they meant business.

I used to only unscrew the side cap and vacuum the chaff. A small amount breaks into sticky greasy powder that collects behind the filter.
After over a year of roasting 2-3 times a week, enough of it accumulated and it caught fire. I roast by the basement window so i easily took it off and through it into the snow. It kept burning for a while.

I was surprised at the amount of powder that fell out of it. The semi rigid aluminum duct had to be replaced as well.

The collector is very easy to clean, i loosened the screws a little and the back popped off, which I will routinely do moving forward, often. The aluminum duct should be inspected as well, just like my fireplace chimney.

Take care and stay safe.

That warning applies for all coffee roasters. Read the owner's manual and pay attention to the care and maintenance section. Place a repeating calendar event on your phone if you have to. The chaff and oils that are produced combined with the high temperatures of whatever heating system it has (gas, electric, IR, solar, whatever) creates a recipe for disaster if the cleaning regime is ignored. Same can be said for an inattentive operator. I roast many different types of coffees and some produce far more chaff than others. Just another thing to watch for.

Thanks for the tip. I just learned this the hard way, with burning chaff for the first time in 13 years of using the Gene Cafe.

When I installed my larger roaster I also installed several fire extinguishers within easy reach as a last resort. I remember one of the presenters at the roasting class I took by USRC saying to always try some water first if you get a fire in the roast chamber. An extinguisher can do damage to the roaster. This is a bit different than a vent fire but worth noting.

The Hottop manual states that you should have a spray bottle of water handy. If a fire starts, lift bean chute cover, spray four of five times directly into the roast chamber, then put cover back on and spray any burning beans if any have ejected. The manual also states that the rear cover should be removed occasionally and the inside of the roaster cleaned with compressed air. But some owners seemingly never clean their roasters. This is what I found in a roaster I recently repaired.

That is NOT a layer of factory insulation. It is years of neglect just waiting for ignition.
Coffee roasters do not catch fire. The beans and debris in them certainly do.
The brand does not matter- maintain your roaster.

Milligan wrote:When I installed my larger roaster I also installed several fire extinguishers within easy reach as a last resort. I remember one of the presenters at the roasting class I took by USRC saying to always try some water first if you get a fire in the roast chamber. . .

If I have a fire, the extinguisher will be used. It isn't time to piddle around with water. Douse that fire; the heck w/the roaster.

I just let the chaff burn. There's was a lot of smoke, but the roaster seems to function just fine. I even plan to try to use the beans from that batch, after I removed about 10 or so that were slightly charred.

Boldjava wrote:If I have a fire, the extinguisher will be used. It isn't time to piddle around with water. Douse that fire; the heck w/the roaster.

This was in the context of the roaster having a quenching system. The USRC they were using had a "oh **** button." If you press it then it kills the gas and activates the quencher.

A bean fire inside the roaster isn't something you'd want to panic and hit with a fire extinguisher immediately. There are other ways to handle it. A vent fire is a bit different.

Milligan wrote:This was in the context of the roaster having a quenching system. The USRC they were using had a "oh **** button." If you press it then it kills the gas and activates the quencher.
...

Context matters. Agree w/you.

I remember correcting a guy once. He had his fire extinguisher mounted on the wall behind the roaster. No!

My extinguisher is always behind me and between me and the exit.