External Chaff Collector on a Diedrich

[elguapo]

Hello,

I posed this question within a thread once before, but it ended up getting lost because it was a little off-topic.

We are getting a Diedrich IR-12 and would like to know if we should get an external chaff collector? The company says it has an internal chaff collector and it's not necessary, but in our experience with our Ambex roasters, they do not work. If you've roasted on a Diedrich of a similar size, what are your thoughts? If the internal one works, does it have to be cleaned after only a few roasts?

Thanks in advance!