Advice Needed: What to do during power failure mid-roast

[AndyP]

Advice needed from experienced roasters. I'm roasting on an Ambex YM5. I was mid-roast on my first batch after the roaster had warmed up to 430 for 45 min, and the warehouse I'm in had a power outage. Quickly found out it was due to roadside utility work. I had no idea what to do, so I unscrewed the rear casing of the machine and hand rotated the drum a few rotations per minute in an attempt to keep the hot parts moving and get the beans out. It started to cool down (from 330 to 200) and after 30 min the power came back on. Is there anything that can be done if this happens again? The manual states that the machine must never be shut down until it cools below 150 deg. to avoid warping the drum and damaging bearings. (I'm the paranoid roaster who waits until 140 just to be safe). It seems totally fine of course. Any experience with power failures on Ambex machines or any other "emergency" situations or tips you can share would be appreciated!

Thanks!

 

[MillCityRoasters]

You did exactly what you're supposed to. Manually rotate the drum to get the beans out and let it cool down.

The big reason you want to get the beans out is because, at some point during the roast, they can scorch hot enough to burn. Most larger roasters come with a handle that engages the shaft on the rear of the drum.

If you need to quench a smoldering roast in a hurry, use a mister to spray water on the beans. Misting works great and is much easier to clean up than a fire extinguisher.

 

[topher]

That can be a scary thing! I use a 60 kilo and have had it happen to me while doing a dark roast. Mill Roaster has already told you did what you are supposed to do. I do have some advice. Next time make sure you turn your motor off. You do not want to get your hand caught in the chain if the power comes back on.

 

[cafdud]

If power outages happen often, I would have a backup generator with manual transfer switch. losing a 60 kilo load would suck, I have a emergency plug in the house and one in the shop, have used it twice in the last year, 3 years ago power was out for three days something to think about.

 

[AndyP]

I did think to turn off the switch, really was more concerned about the roaster being damaged than losing the coffee. But yes- 60 Kilos would be worth the cost of a generator for sure!

 

[topher]

Ha! 60 kilo was bad...what was worse was it happened to me on a 120 kilo. Luckily it came with a handle to turn the drum manually.

 

[ellatas]

This is good advice for roasters with batch sizes less than ~30kg. On larger roasters, however, it is best to keep the coffee in the rotating drum and utilize the water quench to ensure the coffee is not burning before it is released out of the roaster. The batch will be ruined, but releasing a large batch of smoldering beans onto the Cooling Tray can turn the situation into a major fire. Typically on larger roasters, the oxygen level is relatively low within the roaster so the smoldering beans do not have aggressive flames that allow it to spread beyond the coffee. Once released to the oxygen rich environment of the Cooling Tray, the smoldering beans can flame up and spread the fire beyond the roaster. So it is best on larger roasters to take your time, keep the drum rotating and water quench excessively.
On smaller roasters, it is more likely to have no water quench. So it is best to get the coffee out and deal with it outside of the roaster. Since the coffee batch is small, the fuel is small and the risk of fire spreading is low. Nevertheless, you should always have the ability to spray water on the coffee as soon as it exits the roaster.