I would prefer post-roast blending with single dosing to try all combinations. Most of the time, [Colombia, Costa Rica, and Guatemala] can substitute each other for the base, 60% in binary blend. [Sumatra or Sulawesi] could be the other component, 40% in binary blend. Ethiopia doesn't go well with S...

Alan, Congrats!

I snagged 20# when it was still available. I culled through the entire bag and there was virtually no defect. 15# of them were immediately vacuum-sealed and stored in the minus-twenty freezer. It was such a clean cup and it's not a typical dry processed Ethiopian, with a taste profile a bit similar ...

Congrats to your newly acquired roaster and welcome to H-B. Several years ago when I was searching for a commercial sample roaster, the Giesen W1a was on my short list. I was really impressed by its design and functionality. This is the first time I've seen a Giesen user on H-B. If you don't mind, w...

In early days coffee was roasted in a sealed solid drum rotating above the flame. The radiation and the hot air convection heated up the metal of the solid drum, and the drum heated up the beans mainly by conduction. It was not efficient and a typical roast was longer than 30 minutes. {image} Nowada...

Not exactly the flame height. It's the non-linear feature of the perforated drum roaster. In a solid drum the hot air has relatively more time & space to pre-mix, and the subsequent more-or-less laminar-flow through the drum. It has very broad linearly adjustable airflow and heat intensity range. In...

It could be more complicated when charging full load or half load. When charging at lower % capacity (the black arrow, 10 seconds after charge), the beans may localize at the exit (black oval). When charging at full load (the blue arrow, 10 seconds after charge), the beans may be more evenly distrib...

I listed it as an example of the worst case scenario, and it doesn't necessarily apply to a particular model of any machine. However, increasing airflow in this case will result in the increased temperature difference between the hot and cold regions. The burners maintain the same even BTUs, but the...

The complete-combustion blue flame of air-propane mix is very hot, up to 1970*C (3580*F). {link} Don't let the flame directly touch the perforated drum wall. Here are some ancient links of related topic. "Combustion Gases in Coffee Roasting" "Exploring the Huky 500 Coffee Roaster, Part II" And my qu...

The heat source is at the bottom, and symmetrically the bean is also sitting on the bottom of the drum due to gravity while all cold air has been heated up by the flame feeding from the bottom. Fair enough simplification of model. When the drum starts mixing, we can only imagine the beans would expe...