Posted Fri Dec 12, 2003, 5:16pm Subject: Yirgacheffe meets the heat gun
I had the best coffee of my life today and I'm really happy that I roasted it. It was a pound of Ethiopian Yirgacheffe from SM's -- the Horse, not the organic. I followed Tom's advice and aimed for a full city roast. After 2 days of resting I made a fresh pot at work using my cheap burr grinder and my Mr. Coffee. Omigod, it was awesome. I'm not great at describing flavors but the part that really struck me was that as the coffee cooled, it developed a sweet creamy finish that approached a really creamy cocoa flavor.
This was probably my 6th time using the heat gun. I put the roasting bowl inside a corrugated cardboard box to contain the heat better. I'm out in the garage in sub-freezing temps. The bowl is 2-3 quarts so a pound is about an inch or so deep. I've been leaving the gun set at high fan speed/lower temperature. I basically control the profile by raising and lowering the gun. When I want the temperature to move up quickly, I push the barrel into the bean mass and keep it moving. I started with a slow ramp up to the 1st crack and then went moderately fast (about 3 or 4 minutes) to the first snaps of the second crack. I culled 20-25 underroasted beans.
I think I was very fortunate to discover a really great bean just as my heat gun roasting skills are starting to improve. If you don't hear from me in a while, I'm probably blissed out in coffee nirvana. :-)
Posted Fri Dec 12, 2003, 5:38pm Subject: Re: Yirgacheffe meets the heat gun
Ditto. I have been experimenting a lot lately with African coffees (Moka stag and Yirgacheffe from McCauley, Moka Kadir from SM and Red Sea from the Coffee project) roasted via the heat gun. Since all of these, except for the Yirga, is a blend, I have been aiming for a medium to full city roast for the majority of the beans. I have found that cranking it way up far into second crack just kills the subtle nuances, fruity, and spicy notes of the Africans. I have probably done about 15 roasts all together with the heat gun. My Rostos are gathering dust.
My wife, when she sees the containers of roasted Red Sea running low for her drip coffee, takes them out of the freezer and shakes them at me to be sure I am gettting the message. Now if I could just get her to take over the roasting and espresso duties, I could sit on the couch watching TV while she does all the work!
Heatgunroast Senior Member Joined: 10 Feb 2003 Posts: 358 Location: NYC Expertise: I love coffee
Espresso: Dalla Corte Grinder: Mazzer Mini; Zass Vac Pot: Royal Balance Brewer Drip: Various press and pour-overs Roaster: Heatgun, Dogbowl
Posted Fri Dec 12, 2003, 7:01pm Subject: Re: Yirgacheffe meets the heat gun
Well, we three seem to constitute the entire heat gun constituency. Maybe we'll hear from others. Just some observations in no particular order. Note, I roast only for espresso:
I've had some of the same satisfaction with Yirg. In fact, something is going on with all the brighter coffees. Centrals, Kenya. These seem to benefit from a faster roast than my usual (8+ instead of 11 minutes). Previously, I allowed a slow, "light" 2nd crack stopping when I would still get a fairly dry bean. Recently, the instant 2nd starts I hit the beans heavy- - forcing a fast roll (all within 20 secs) and being set up- - prepared- - for a fast cool down. Still, only light oil. Quite good as single variety espresso- - -against all common experience.
Decafs. About 40% of what I roast is decaf. I hope this doesn't reflect on my character, but I love that musty smell (or stinky feet, as someone observed). I still roast green blends in my stash, but my favorites are the singles. Currently its Harar. For a decaf, big flavor, good body, hints of complexity but getting that is tough with decafs.
I've got some thoughts on how to monitor temp during the roast. Not too optimistic, but I'll report back in a few weeks. Could happen. Even so, I'm not sure what it will add.
Jim and Michael: Have either of you combined the gun with grill top? When weather warms up, and if you're set up for it, try it. I can achieve essentially the same roast with the gun alone or with the gun and grill, but after lots of roasts I believe the combo is superior. I have some weak speculations why, based on Jim Schulman's weak speculations about the "smoothness" of the ramp (my words- - -I think that's what Jim means). The steady under-source of heat may mitigate or buffer the inevitable variations of a hand-held application of heat. We'll see about that. Could be a bad theory, but doesn't alter my experience. Also, it helps if you are doing a larger roast- - -I think it would take some critical skills with the gun actually into the beans.
I find that when I get to a pound, I'm up to 15 minutes and more of roast time. The total difference between doing a pound and a couple at 10 ounces (at 12 minutes and as much as I like to go) is no more than 5 or 7 minutes. And if I do 2 roasts, I get to do diff. varieties.
Posted Sat Dec 13, 2003, 11:28am Subject: Re: Yirgacheffe meets the heat gun
Martin, I had read your earlier posts here and on alt.coffee about using the heatgun/bowl in conjunction with a gas grill outside. I noted that you did that for a while, and then went to heatgun only with acceptable results. A few months ago when I first started with the heatgun, the rains had already started in Seattle. Our gas grill is in the backyard and is not under cover. So from the very beginning, I wanted to try a technique in which I could use the heatgun outside during the winter. I have a covered front porch, and that is where I am doing my heatgun roasting.
Now come spring and summer, just for the heck of it, I will probably try firing up the Weber and roasting a batch or two in conjunction with the heatgun. I am not thrilled with the heat output of the Weber, but I will give this a try. I will always want a techique that I can do under cover in the winter.
One favorable benefit of the heatgun technique is that I am now drinking a lot more espresso. With the greater batch sizes, I can at one sitting roast enough espresso to hold me for a week. I have found the optimum batch size for a week is 1.5 cups green by volume. This gives me about two cups by volume finished product, which neatly fills a 0.5 liter air-tight clamp-seal french preserve jar that I get from Pier One. I can do this batch, start to finish including cooling in less than 15 minutes. Using the Rostos (only one of which is currently working), I would have to do two batches that would take me approximately 30-40 minutes start to finish. With the espresso allowed to age for a few days (my favorite espressos are Malabar Gold, Liquid Amber and Moka Kadir, all of which benefit from aging for three days or so after roasting), I keep the jars in the freezer and I have pretty good quality all the way to the end of the jar.
For drip, I am doing three cups green by volume at a time, which gives me four cups by volume finished product. I am storing this in larger clamp-seal jars, and this quantity lasts us about a week.
Do keep us posted in temperature monitoring. I am getting reproducible results just by sight and sound, but am always interested in other techniques.
Posted Sat Dec 13, 2003, 11:42am Subject: Re: Yirgacheffe meets the heat gun
I've been trying to do some temperature monitoring with limited success. I have a Radio Shack multitester with a thermocouple that I paper clip to the side of the bowl. I can't really count on the temperature reading itself because the end of the couple moves when I stir the beans. However, I can at least see whether the temperature is climbing or not and sort of gauge how fast. That helps me a lot because my sense of smell isn't good enough to tell me how quickly the beans are warming.
I do roast more by smell and sound than visual cues because of poor lighting conditions. However, even the limited feedback I am getting from the thermocouple seems to have flattened my learning curve.
Jim
PS: Made the Yirg with Rocky/Chemex this morning and it was even better. :-)
Heatgunroast Senior Member Joined: 10 Feb 2003 Posts: 358 Location: NYC Expertise: I love coffee
Espresso: Dalla Corte Grinder: Mazzer Mini; Zass Vac Pot: Royal Balance Brewer Drip: Various press and pour-overs Roaster: Heatgun, Dogbowl
Posted Sun Dec 14, 2003, 6:49pm Subject: Re: Yirgacheffe meets the heat gun
jliedeka Said:
I When I want the temperature to move up quickly, I push the barrel into the bean mass and keep it moving. I started with a slow ramp up to the 1st crack and then went moderately fast (about 3 or 4 minutes) to the first snaps of the second crack. I culled 20-25 underroasted beans. Jim
I wanted to pass along some good info by way of Ed Needham. He posted this on alt.coffee as part of a rather long back-and-forth essentially on the stability of the ramp. Here's part of what Ed offered:
"Carl Staub, in an excellent article on roasting said that it is critical that the beans do not 'exotherm' during the roast. What he meant by exotherming is that the roaster would not lose momentum during the roast and actually allow the beans to put off some of the stored heat until the roast is finished. The consequences of this is that the complex web of chemical reactions go awry and strange tastes or muted tastes can occur. A quote... http://www.sweetmarias.com/roast.carlstaub.html from Carl Staub: "Once carmelization begins, it is very important that the coffee mass does not exotherm (lose heat) or the coffee will taste "baked" in the cup. A possible explanation is that exothermy of the charge mass interrupts long chain polymerization and allows cross linking to other constituents." By using the heat gun only, the beans, most likely are experiencing numerous endotherms and exotherms (heat in, heat out), and their taste, by your report suffers. Using the grill heat as an additional, stable heat source probably allows the beans to continue a steady climb on the heat curve and avoid the exotherming Staub cautioned about. Don't know for sure, but it sounds good."
And maybe more relevant is a later comment by Staub about the "Maximum Environmental Temperature" which Staub puts at 520 F. and for which he offers reasons. I took this to heart since I like a fast ramp going into first crack. Although I've been intuitively careful and really speed up my stirring, I'll ease up some on this ramp. It did make me think though about the temp of the beans if you actually submerge the gun into the beans. Martin
Posted Sun Dec 14, 2003, 8:51pm Subject: Re: Yirgacheffe meets the heat gun
You know, I had been following this exchange on alt.coffee as well, and I am not sure I agree with Ed's concerns. I think that if you were roasting very large quantities of coffee via heatgun, temperature stabilty and stalled roasts may well be a concern.
But when I look at the quantity that I typically roast, in a relatively confined space, the time the total roast takes, in a relatively thermally-stable environment, in close proximity to the heat source, and stirring constantly, I am just not seeing any visual or taste evidence of exothermy producing baked tastes in the cup. I have had baked coffee and am reasonably certain I can detect it.
So although Ed's interpretation may be theoretically correct, I think that where the theory meets the application is where I am dubious. At least, in terms of how I apply roasting techniques. Clearly there is a dissertation in here somewhere.
Posted Sun Dec 14, 2003, 10:07pm Subject: Re: Yirgacheffe meets the heat gun
MGLloyd Said:
But when I look at the quantity that I typically roast, in a relatively confined space, the time the total roast takes, in a relatively thermally-stable environment, in close proximity to the heat source, and stirring constantly, I am just not seeing any visual or taste evidence of exothermy producing baked tastes in the cup. I have had baked coffee and am reasonably certain I can detect it.
I agree that exothermy is not normally a problem for us. It is worth bearing in mind though. Since I'm roasting in sub-freezing temps I've found a cardboard box to contain the heat helps a lot. Without it I'd have to work a lot harder to keep the bean temperature climbing. I have yet to bake my beans so it can't be that big of a problem.
I thought about heating the top and bottom with a heat gun/grill but the heat gun gets the beans plenty hot in a reasonable amount of time. For now I'm looking at better insulating the bowl and trying to get an accurate, or at least consistent, temperature reading.
Posted Mon Dec 15, 2003, 2:31pm Subject: Re: Yirgacheffe meets the heat gun
Do either of you preheat your bowl with the heat gun before dumping the beans in? I do not, just as I do not preheat the Rostos before adding the beans. I wonder if preheating the bowl contributes anything to either the speed or quality of the roast.
At this time, I start with the beans in the cold bowl and start heating with my heatgun on the low setting until things are a pale to medium tan. The higher air flow at the low setting helps to agitate the beans. I then shift to high and push it to first and second crack relatively more quickly. So I am ramping up my roasts albeit I have no time or temperature readings to speak of.
Posted Mon Dec 15, 2003, 4:44pm Subject: Re: Yirgacheffe meets the heat gun
I haven't tried preheating the bowl yet but I've thought about it. I'm actually just on my way out now to roast some PRYS. I think I'll give it a try. It might speed up my time to 1st crack a bit which wouldn't be a bad thing. Unfortunately, I really don't keep time so I have no baseline. I can at least give you my impressions afterward.
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