Roasting Techinques

I’m not sure what other roasters’ approaches to new coffees are, but i thought i should write a little post about what we do when something new rolls into the roastery, be it a new crop or an entirely new coffee. It may also help those reading my cupping descriptions to understand what exactly is going on…

I’d like to think that this is a pretty common approach, though i suspect the reality may be a little more shocking, where companies just stick greens in the roaster and pull them out when they are “brown”. Again, please comment.

A lot of this is down to gut feeling i suppose, and the vibe you get from the coffee your dealing with, so bare with me.

First off, the green coffee is checked out: colour; smell; size; density; etc.. From there you get an idea how exactly you should treat it. Big, aged or soft beans will need a much more gentle approach as opposed to somthing smaller (peaberry) or harder (SHBs), so the start temperature may vary (anything from 380°F to 420°F).

During the roast itself, the fuel valve is adjusted, allowing you to control the rise of temperature (a nice, steady rise is what your after – too quick and you’ll scorch and blister the coffee, too slow and it’ll bake), as first crack is reached, the fuel valve is closed a little, slowing down the caramelisation process (the Maillard reaction – a reaction between amino acids and sugars present within the bean whereby desired flavour is developed – research it for yourself as i’m a little rusty, and it isn’t the objective of this post!). Once first crack begins to slow, the valve is opened a little further where it sits until desired bean temperature is reached.

Now, back to the topic in question. At James’ Gourmet Coffee, for each new coffee we wish to cup, we roast to three basic profiles, and then judge from there. The first is a light roast, around 427°F, then a medium roast, around 435°F, and finally a darker roast, usually about 442°F. From there we can taste each roast profile and see which roast will allow the most to be gained from each coffee. If we feel that perhaps a certain coffee tastes a little too green in one profile, yet the next temperature up is a degree too far, then we go back to the roaster and re-profile a closer range of temperatures (sometimes just 1°F apart!). If that is what it takes to get the best from that particular bean, then that is what must be done.

I’m writing this after we profilled six coffees this afternoon – so thats eighteen different samples to cup tomorrow! Yey, bring on Friday!


~ by E-83 on June 7, 2007.

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