Espresso! My Espresso!
Improved Roast Profiling
by Randy Glass - Copyright 2010 - All rights reserved

      I am easily bored with any activity that I feel I have either mastered or have reached the pinnacle of my ability (marriage being the exception). I usually last about 6 years when that takes place (marriage being the exception). Sometimes it necessitates a change of scene and others complete abandonment (ditto). I have been around the coffee scene for over 9 years, and one thing I have learned in that time is how little I know and how much there is to learn. I still feel like a novice in this enterprise.
      If that is a general truth, then when it comes to coffee roasting it is a law. Talk to three coffee roasters and you will get at least four different theories abut coffee and how to roast it. Talk to someone who uses a Sivetz fluid bed roaster and you will learn all about why drum roasters are bad for coffee, and vice versa. How long is too long? How fast is too fast? it never ends, and probably never will as long as there is coffee and someone to drink it left walking the face of this planet.
      I recently modified the roast profile I have been using. It is nothing radical, and I cannot, nor will take any credit whatsoever for this other than taking the time to read about it, apply it, and document it here. Although this procedure was written with the Hottop model "B" in mind, it can be easily applied to just about any coffee roasting appliance that allows the user to control the roasting temperature.

      What I had been doing previous to this change was dropping in the beans when the roaster hit about 250 to 275F. I would let it go, full bore, until just before first (about 395 F. bean temperature using a probe thermometer). At first crack I would begin to drop the temperature in an attempt to get about a two minute dwell duration between the end of first crack and the beginning of second. Manual ejection took place at about 10 to 30 seconds into second depending on my mood.

      I had read a report or three on a web forum that elongating the drying time had its benefits. The theory goes that by drying the beans more slowly and earlier in the roasting process allows the internal bean temperature and moisture level to be about the same as the external bean temperature so the flavor of the inside of the bean can develop more fully. It does make sense, and beyond the science, it certainly seemed worth trying in order to get better coffee.

      Here's what I now do:

Start the roaster as always using maximum time and maximum temperature as the programmed points.

Allow the roaster to go through its preheat mode and drop in the beans at around 250 F.

Time goes by, and as the temperature rises and hits about 285 F. I begin lowering the heating element's power. The rate of temperature increase dictates how much to lower the heating power. The goal is to get the roaster's environmental temperature to level off around 300 to 310 F. or so. It is important to not let the temperature go down- you want the rate of rise to dramatically slow, or level off for a while. It takes a little practice but it is not that difficult once you learn the way your roaster reacts.

Hold the temperature at that point until the beans have gone through the drying phase. You will know that by watching the beans' color. They will go through the bright green phase, and then start to turn beige and then tan. Your goal is to anticipate this change, and just before the beans get into the tan phase you will want to turn the heat back up to 100%. The theory here is that an electrical heating element has a bit of lag, and as soon as the coffee is 'dry' you want to begin the ramp up to the final roasting phase. So you are trying to anticipate the point at which the beans are dry enough to finish the roasting process.

If you have a bean probe you can more accurately anticipate first crack which will begin at about 395 to 400 F. depending on the accuracy and placement of the probe. Just before first starts, or as you hear the first click, turn the heat down. As first become active you can turn the heat down to around 50%. The beans will become exothermic through the Maillard reaction and the additional heat in the roaster and element will be sufficient to finish the roast in most environments. Once again, your goal is to get around a 1 to 2 minute time duration between the end of first and the beginning of second.

Eject at the point you desire. For espresso I eject about 10 to 15 seconds into active second. For other brewing methods a bit earlier depending on the coffee being roasted, of course. As an example, Colombian can be excellent for drip if the roast is stopped midway between first and second, depending on the rest of the profile.

      Using an electrically powered coffee roasting device is not necessarily the best choice for roasting. The lag times when trying to change the temperature in the roasting environment can make it a challenge to get repeatable results when controlling the roast manually as outlined here. But for most of us home roasters, an electric appliance is the only real choice. The roast as outlined here gives you some excellent indicators that are universal while easily seen or heard which makes this an easy way to get better coffee.

      I believe that this profile brings out a more balanced flavor, a smoother taste overall, and gives more definition to the intricacies of the varietal flavors. Give it a try and let me know what you think.