Received my 10 lbs yesterday and put in 3 roasts today.
I roast on the Huky 500T with a charge size of 375. I went up to 400 for the R & L because I have so much of just one coffee. I didn't realize I would have to adjust for this in a pretty significant way, so there are a couple of hiccups on the roast curve. Anyway, here it goes:
I wanted to understand how the impact of different heat levels on the development of washed Ethiopian coffees. There are three approaches I'm testing for:
1) Full heat, short development: The idea is to push the coffee as hard as can during development, but shorten the overall development time. I like to approach of full development with limited sugar caramelization for maximum fruit/florals and sweetness with little to no roast flavors.
2) Low heat, elongated development: There is this fear in my head that high heat post 1C will burn off florality and aromatics. So why not go for what many roasters do, which is try to use the lowest possible RoR post 1C that still provides full development.
3) Somewhere in the middle.
My first roast:
The RoR crashed at 1C, but I did not back down from heat at 95% (4 KPA on the Huky). The 1C was insanely uniform and loud, like a machine gun. I believe that the RoR crash is simply the intense exothermic reaction overloading the probe. It does not recover because I dropped the coffee before the RoR could pick back up.
Cupping notes (48 hours post roast): The full heat during 1C lead to dry, roastiness. Because the charge temp was lower with insufficient airflow, this roast was both slightly underdeveloped and lightly charred. You can't tell that it's charred from visual inspection (no tipping or scoring), but you can tell by the taste. I don't think I will be applying such high heat at the end of the roast for this coffee. The fruited notes were super fresh and floral, however. Wet aroma gave me peach, honeysuckle, and slight jasmine in a freshily bloomed kinda way.The developed cola notes were not present. Tasting notes were the same as the smell, but very subtle and delicate accompanied by the roastiness and slightly sharp acidity.
Same situations as the first roast, except I incorporated a higher charge temp in order to compensate for the higher charge weight & density of this coffee. I also dropped the heat earlier going into 1C vs. the first Roast (where I didn't drop the heat at all. The 1C happens a little later, and in a more controlled way, albeit the crash still happens (all the while the 1C is rolling like crazy). It's a false crash, just like the 1st Roast.
Cupping notes (48 hours post roast): This roast was much more balanced and intense. I believe it's because of the hotter charge and faster roast allowing more energy to penetrate the coffee all the way through. The aromatics were ripe peach flesh, honeysuckle again, and a lightly medicinal/musky south american cooking spice backdrop (what SM must be alluding to as sarsaparilla). There were no smoky roast notes on this one. Beautifully juicy, but light in weight. Tea-like body with cleansing finish. The acidity was very mild. I really liked this roast, but I would prefer to develop it slightly further to get more aromatics and try for a more complete development. I felt this is 90% of what I wanted from this coffee.
I wanted to speed up the dry, so I bumped up the airflow a little bit (55 up to 60 on the variac). This seems minute, but the difference is pretty huge. I also lowered the heat to 3.5 KPA 10 degrees before anticipated 1C. Then lowered to 3 KPA when rolling 1C started. I decided to try and finish 1C on this roast to see how it compared to the other two roasts. The result seemed to have a significant roast characteristic (which may not be bad). But since I'm looking for purer fruits/florals, it may not be the roast I prefer...
Cupping notes (48 hours post roast): As suspected, this coffee got developed further than I wanted. The result was a really nice baker's chocolate/cocoa powder bitterness followed by the slightly musky cooking spices (sarsaparilla), and a subtle but present peach note. The peach note here wasn't fresh peaches, but slightly cooked peaches (baked as opposed to grilled). Beautiful coffee despite the fact that it's further along in development than I prefer.
I think the ideal roast is somewhere between Roast 2 & 3. I want a little bit more of the sugar caramelization notes to fill out the body of the coffee so that the fruited peach and floral notes have some weight as support. This is a beautiful, delicate Ethiopian washed coffee. Not as intense as Ethiopians can be, but really delightful nonetheless. I would personally give this coffee an 87 as I've had Ethiopian washed coffees that have what this coffee offers plus more and in a significantly more intense way. There could also be more sweetness to the coffee, but the musky backdrop is in itself very interesting and pleasing and I'm glad to find that in this coffee nonetheless.