MikeSD Senior Member Joined: 10 Jan 2013 Posts: 43 Location: Florida Expertise: I like coffee
Posted Thu Feb 7, 2013, 12:54pm Subject: What does unrested coffee taste like?
So I've been learning how to home roast without much success. I've been reading a bit and I think the problem is that I'm not letting my coffee rest enough. I've been making small batches the night before, and using them the next morning/afternoon.
I've had two outcomes both of which I'm not happy with. 1) I roast too long and can't tell the difference from one origin to the next. It all basically tastes the same. Not terrible, but unremarkable, and really just not worth the trouble of home roasting. 2) On lighter roasts the coffee tastes a bit sour and what I might call astringent.
I had read at first that you should let your coffee rest from 4 - 24 hours, but recently I've been reading that it can be better to let it rest for several days or even a week. I read that that coffee "develops character" and such, but I'm not really sure what that means. My question is, if I'm getting a fair amout of sourness, could it be that I'm not letting the coffee rest enough?
oldgearhead Senior Member Joined: 25 Jan 2010 Posts: 354 Location: Go Colts! Expertise: I like coffee
Grinder: Virtuoso by Baratza Drip: Chemex,Dilongi DCM900 Roaster: 1/2K Fluid-bed
Posted Thu Feb 7, 2013, 1:18pm Subject: Re: What does unrested coffee taste like?
'Sour' coffee usually results when the outside is roasted but not the inside. A common problem with 'popcorn poppers'. I use the rule of 4 for my roasting: 4 Minutes for the drying phase (need 2-3 minutes at least a BMT of 230F. 4 minutes in the ramp to first crack phase. BMT hits 400F and ET air needs to be above 500F. 4 minutes in the finish phase (drop ET to stretch first crack, and stop roast right before second crack) 4 days rest.
Posted Thu Feb 7, 2013, 1:43pm Subject: Re: What does unrested coffee taste like?
I have found that a lighter-roasted coffee is usually more acidic, and I don't like much acid in my coffee at all. What other people like I find unpleasant. It's not that I don't like acid flavors, but something about the acid in coffee is just not pleasant to me. As a result, I tend to like lower-acid coffees like Indonesians, roasted darker so they are less tart.
But it isn't clear to me whether the acidity/astringency in your lighter roasts is because of poor roasting techniques, or because you just find them unpalatable. Most consumer coffee is low-acid, non-specialty, not-light-roasted beans, so perhaps it's a new flavor for you. Higher astringency can also come from overextraction. This might be caused by too fine a grind, or brewing too long for the method.
I know there are ways to roast that reduce the acid, such as lengthening the phases of the roast and using different types of heat application (say hot air roasting vs. radiant heat). Unfortunately I am not conversant enough and don't have the convenience to look this up right now :-) so maybe someone else will chime in or a search on this site will help you.
As for the resting question, I don't think resting changes the acidity at all. It sort of "ripens" the flavor, the aromatics mostly. Different coffees benefit more or less from longer or shorter rest times. Sweet Maria's often provides a recommended resting time for their greens. Usually no more than a day or two is needed though; fewer coffees benefit from long rest times.
yakster Senior Member Joined: 25 Feb 2009 Posts: 1,006 Location: San Jose, CA Expertise: I live coffee
Espresso: Gaggia Factory / La Peppina... Grinder: Vario / Kyocera Vac Pot: Yama 8 + Pyrex Lox-in Rod Drip: Brazen / Kalita / Chemex /... Roaster: Behmor
Posted Thu Feb 7, 2013, 3:29pm Subject: Re: What does unrested coffee taste like?
I find that most coffees peak at 3 - 4 days of rest for lightly roasted coffees. Some coffees benefit from longer rest, up to about 7 days, but most of the time the coffee is acceptable drinking it the day after roasting.
It sounds like the roasts you described are "baked" or flat for the longer roasted coffees, probably due to too long a roast and an underdeveloped roast where the outside of the coffee is darkened but the inside is still very light. You can compare the color of the ground and the whole coffee after you roast it. If they look the same color, it may be baked, normally it should be a bit lighter on the inside, but if the ground coffee is quite a bit lighter than the whole bean then it's likely underdeveloped due to too quick a roast with not enough time spent in development.
Posted Thu Feb 7, 2013, 5:35pm Subject: Re: What does unrested coffee taste like?
I call it "extra bright". Not exactly bitter. In looking at my old notes, coffee brewed immediately after roasting to me lacks development of cocoa and darker notes. Sometimes has a "zing", not exactly effervescent, but along those lines, with occasionally something I think of as a "feeling" of brightness.
Flat coffee is exactly like yakster says - baked coffee. Not bright, but also lacking depth and many times just a flat flavor when fruits and floral hints should be present.
I also think of an analogy with meat: many times, the key to great flavor compounds is in the sear of the meat. Browning is the magic that adds flavor where it hadn't existed before.
BUT, sear too hot and the result can be a combo of some flavor compounds and off flavors from combustion products. Searing too hot means a limited time for proper browning to happen, you get the color but not enough time to get a lot of the more complex reaction products of browning.
Sear too cool, and you'll still get browning and some of the flavor, but the meat will taste flat. Temp isn't high enough to get the amino acids and sugars to combine into the REALLY complex taste compounds.
Works with chicken, fish, pork, beef... and browning is one of the most important parts of roasting coffee.
I've done low-load high temperature coffee roasts in both my behmor and my BMHG. We're talking 1st crack under 6 minutes, finish at or just past 2nd crack in about 8 minutes. The taste of it properly rested is on the verge of scorched, and somewhat off-balanced. Some of the big forced air roasters that do a roast that quick have similar flavor.
I've also done roasts where first crack starts at 17 minutes, and struggles to finish by 21. This is "baked", and it is pretty... boring.
For me, my best roasts seem to be when first crack starts around 8 minutes, and finished by 12 minutes or occasionally 14 minutes. I try and really stretch the first crack - thinking about browning, it gives time for the moisture that just got released from the cracking to escape and evaporate (moisture can damp town temperature and stall browning), and allows a lot of time to develop nice browning in a good temperature range that supports it (for coffee that's around 390°F - 430°F). That's the hypothesis, anyways.
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
MikeSD Senior Member Joined: 10 Jan 2013 Posts: 43 Location: Florida Expertise: I like coffee
Posted Thu Feb 7, 2013, 7:35pm Subject: Re: What does unrested coffee taste like?
I use an air popper. I toggle the heating element on and off in such a way that first crack starts at about 8 minutes and second crack starts at about 12ish but I've been stopping it at about 10 or 11 to keep it at about full city I believe. I'm certainly still learning but I'm thinking this is a pretty decent extension of first crack. I just wondering if the taste I'm tasting might be that I'm not letting the coffee rest. I'm thinking the best way to find out is probably just to wait.
Posted Thu Feb 7, 2013, 8:28pm Subject: Re: What does unrested coffee taste like?
What coffee/coffees are you roasting? Some regions and types are more forgiving than others. I've hade Ethiopians that tasted terrible until I found just the right roast level, then I found out how good they can be- I hate it when I miss the mark on those! Many varietys are not so finicky. Most coffees I've roasted are pretty good the next day, if they're good at all. Some better than others. They all definitely change and develop their flavors with more rest.
MikeSD Senior Member Joined: 10 Jan 2013 Posts: 43 Location: Florida Expertise: I like coffee
Posted Thu Feb 7, 2013, 8:42pm Subject: Re: What does unrested coffee taste like?
CoffeeRon Said:
What coffee/coffees are you roasting? Some regions and types are more forgiving than others. I've hade Ethiopians that tasted terrible until I found just the right roast level, then I found out how good they can be- I hate it when I miss the mark on those! Many varietys are not so finicky. Most coffees I've roasted are pretty good the next day, if they're good at all. Some better than others. They all definitely change and develop their flavors with more rest.
Posted Thu Feb 7, 2013, 9:06pm Subject: Re: What does unrested coffee taste like?
Lately I've been roasting a lot of Brazil (Conquista) and Mexican (Chiapas). Both are pretty easy to get good, and really great at best. I generally try to stop my roasts just after first crack to get the most flavor. The Conquista tastes like a sweet smooth mocha and the Chiapas- has a unique flavor I can't quite describe but it's just super, maybe a bit nutty? My stash right now is mostly that along with some Ethiopians that I get right maybe half the time- oh well when they're good they're great! Maybe we can get some more feedback on this subject.
If you're stretching first crack, then push the Ethiopia to the first few crackles of 2nd crack. Technically, this is Full City, but it acts as a really nice City+.
Sour in an Ethiopia (or Uganda, and especially the lemony ones like Tanzania and some of the Kenyans), in my experience, is encountered when roasted toward city or close to that light. The fruits and florals of Africans really benefit from good browning development and some roasting notes - but NOT at the end of 2nd crack. IMO, both Caribou and Starbucks take the Ethiopia coffees WAY too far (dark, oily beans roasted to near-Vienna).
I'm not sure how you'd do it in a popcorn popper, but if you have a thermometer, try a "drying" phase. Start your roast, but after the first minute, temper the heat and if you have a thermometer, keep the bean temp around 250°F for minutes 2:00 - 3:30, then ramp up and head toward 1st crack. If you do this right, you'll hit 1st crack start (which will be a bit more muted) around 8:00-8:30. Ramp back and maintain for 1st crack, try and stretch it for about 3 minutes if you can, then gently nudge it toward 2nd crack when the 1st crack starts to subside. When you start hearing the crackle of 2nd crack, dump and cool the beans immediately.
That's the other thing - slow ramp-down of the cooling phase can act like a stalled roast, and this can mimic flavors of baked coffee. I'm not sure of the mechanism, but from experience I know that once you're past 350°F, you don't want to have the bean temp drop - and when you're done, you want to be done NOW. Make sure you have a very good cooling strategy.
With a popcorn popper, since you're really only dealing with ~100-200g of green coffee, one effective cooling strategy if you don't have a forced air or vacuum cooler, is to toss the hot coffee beans into a cooled stainless steel bowl and stir/agitate it until the temp equalizes. It's really decent at sucking the heat off the beans, and in the end the temp will be above the dewpoint so you won't have to worry about condensation. Might be worth a try.
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
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