Girl Talk: a video wherein I discuss different styles of roasters and how they use airflow

Girl Talk: a video wherein I discuss different styles of roasters and how they use airflow

In this video I talk about different styles of drum roasters and how they use airflow differently depending on the placement of the blower in relation to the energy source. There are a number of styles that I don't touch on, namely pure convection roasters or even the Loring Smart Roast which is billed as a hybrid roaster but seems to me to definitely be more convection based. Anyway, here's the video.


#1 Contamination through closed airflow

Hi Chris, great video. It's quite an impressive dollhouse you've got there.

A lot of roasters talk about the risk of having closed or semi-closed airflow during in particular the later stages of a roast, due to contamination of the coffee with smoke. Have you found that to be an issue during your roast experiments? Does it only occur in the cracking stages?

Also, on the Probat UG22 that I work with, the airflow dampener sits between the fan and the drum - right on top of the drum housing. Would that have an effect on the airflow dynamics/back pressure/anything else?

Cheers From OZ


#2 Hey Tuli, so great to hear

Hey Tuli, so great to hear from Down Under. IN the UG22 and other Probat models, airflow is a much different issue and smoke definitely does enter the picture when you use the damper. Since the main exhaust is at the top front of the drum, it actually pulls more energy over the chargem as opposed to a roaster design with the exhaust in the rear of the drum. Also, the energy input with the Probat is such that it's just much more effective to make all adjustments to gas instead of airflow.THat in mind, finding the sweet spot for your damper, including the one on the exhaust coming off of the blower is crucial to really nailing down the moisture loss numbers in the Probat.

#3 Thanks Chris, that's a very

Thanks Chris, that's a very logical/interesting perspective on how to use the Probat.

I'm glad you mentioned moisture loss - it's a variable that I am struggling to get my head around and correlate with both flavour and roast profiling. I've heard many theories and pseudo-understandings, but haven't seen anyone using moisture loss data to effectively guide their profiling as yet.

Any chance of a post dedicated to moisture loss - or at least a bit of an elaboration? :)