Roasting, Resting and Brewing Dark Roasts

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
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#1: Post by drgary »

Scott Rao wrote: If I were forced to drink a dark, oily roast, I would not rest the coffee for more than a day, as the coffee will likely taste a little rancid within a few days. (And of course I would add salt, haha.) I don't find coffee from classic-drum roasters benefits from more than a day or two of rest, unless the coffee is what I would consider underdeveloped.
The Scott Rao quote above originates in one of his marketing emails. It was cited in another thread where a discussion of what I'm posting here would take that thread off topic.

I think that Rao's advice above is incorrect, probably because of a bias against dark roasts. I like a broad spectrum of roasts, from very light to fairly dark and oily. I rest and brew them differently and to be fair, Rao's recommendation of a steadily declining bean temperature rate of rise (BT ROR) in his book, Coffee Roasting Best Practices does not, as he writes, necessarily apply to dark roasts.

One of my favorite coffees is Mysore Nuggets, which I take 10 sec into 2C. It's a dark roast because it has crossed the threshold of 2C, and within a week of rest time oil is released from the surface of the beans. I prefer to roast this with an increasing BT ROR toward the end of the roast, as suggested in this wonderful post by Neal Wilson. His suggested dark roast technique purposely develops the beans more on the surface than their core and preserves desired flavors developed prior to 2C as does the very brief time in 2C.

I also on occasion buy traditional dark roasts from Saka Caffe Neapolitan coffee available from Cantina Coffee in the US and from Caffe Trieste in San Francisco. For either of these I may add a demitasse spoonful of sugar but often do not do so. I do not find that either of these coffees goes rancid in a week. The Saka blend is often a month or more past roast and is still excellent to my taste.

Saka's Top Selection is a favorite (I prefer all Arabica because I don't easily tolerate the intense stimulation of robusta beans in some blends), and I usually brew it cool (178F/81C) and ristretto. It's also successful as a normale at 202°F/94°C, especially with a demitasse spoon of sugar added. My ristretto and cool preparation style concentrates the chocolate and anisette flavors and is also great in a milk drink.

Caffe Trieste's Italian Roast Espresso is another favorite that is darker and oilier than the Saka Top Selection. I find it sweet, chocolatey and bitter and also brew it cool (178°F/81°C) to reduce bitterness. I really like it in milk drinks. It's been awhile since I've had it, and I don't remember whether I pull it as a ristretto or normale.

I've found that dark roasts also do well when brewed in moka pots, where the temperature profile starts cool and can be ended before boiling to emphasize caramel flavor notes.

Roasting Technique

I currently use a North TJ067 propane drum roaster (equivalent to an early Mill City 1Kg machine), with a perforated drum that may be a one-off factory mod for that model. I may soon again have an IKAWA Home roaster that has its own characteristics for successful dark roasts. OldmatefromOZ posted this suggestion for replicating a Neapolitan roast. His method works well on my North roaster, but roasting 1Kg or less may differ from production roasting in this style.

I don't know how Caffe Trieste's production roasts are achieved, but for my drum roaster, I would attempt that roasting style using the Neal Wilson technique and taking it further into 2C. Each roaster has its own characteristics, but for mine I would take it about 10°F/5.5°C darker to start.

What I WOULD do for a good cup of coffee!

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#2: Post by ShotClock »

This is an interesting topic for me - I am a sometime fan of dark roasts, and am also encouraged in this direction by my wife, who enjoys acidic coffees much less than me.

I drink a fairly reasonable amount of Saka (recently I'm enjoying Crema Bar), and tend to brew it in a similar way to Gary: 80s espresso profile on the decent (short preinfusion lever shot around 80C), with an EPHQ basket and a ratio from 1:1 (Crema Bar) to 1:1.5 (Gran Bar). This makes great shots with or without milk, and I never add sugar - I don't find these shots at all harsh or bitter if the temp is low enough. The 80s espresso profile massively improved this for me, and allows me to drink pleasurable nutty ristrettos without harsh, bitter notes.

Roasting in this style (or otherwise into second crack) has been difficult for me, and I'm not as happy with the results as with most of my roasting, which is done in the medium-light range (maybe 15-25F past the onset of FC, depending on the coffee).

My best results have been using an approach similar to that described by Neal. I use a declining RoR "Rao style" roast up to FC, going reasonably quickly so that the overall roast time doesn't get too long, and I don't stall out before the end of FC. Once FC has finished, I increase the gas to the last cut before FC, then maybe another increase after that. Similar to Gary, I'm not aiming for Italian roast levels, but rather 10-30s into SC. Mostly I'm using dry processed Brazil greens for this, sometimes Sumatra (although I'm not much of a fan of wet hulled coffees) or a chocolate bomb Guat or Mexican. Gary - I'd be interested to see some of your roast profiles if you would be willing to share them. Particularly the one styled after OldmatefromOZ. I'll see if I can dig out one of my better profiles so that we can compare.

I've found that resting time can be as little as 4-5 days for espresso, but I almost always prefer a week or so.

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#3: Post by drgary (original poster) »

This is the Neapolitan style roast following the method of Oldmatefromoz.


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#4: Post by another_jim »

I grew up in Munich, Germany (army brat), and my best friend's dad was a coffee roaster. The city's roast style was a roughly full city roast that began to show oil after 4 to 6 days. The custom was that coffees were considered too fresh before they showed oil, and too stale after the oil evaporated, so they were considered best during a window of about 7 to 10 days. Consumers checked for a shiny milk chocolate color.

He also did cinnamon roasts of fancy origins for the "Preussische Zugereisten" (actually people from Hamburg and Bremen), but I don't recall what the resting instructions were for them. I do remember him proudly serving a Marogagype that tasted like white wine soaked walnuts, and had us wondering if it was coffee or something entirely different (his Hanseatic customers loved it).
Jim Schulman


#5: Post by LittleCoffee »

I've been thoroughly enjoying that other thread, though I do feel like a first grade elementary student who has stumbled into a University lecture on quantum mechanics by mistake :D

I'm a simple guy and enjoy a dark roast. My go to is a dark roast Sumatran Mandheling. I do think Scott Rao is directionally correct - I drink it from day two post roast (can't really get it any quicker) and I find it's exceptional the first 5-7 days after which it's merely good and very enjoyable (I would absolutely not agree with the rancid label though!). There is also a very noticeable change in grind setting needed over that period - to the point where I'm almost re-dialing in every day - directionally if I'm increasing dose I need to go up by 0.5g a day, and if adjusting grind setting, then it's 1-2 notches on a Sette 270.

I also buy 1kg and freeze 4x200g batches as soon as it arrives, which is usually day 2 post roast. I find that for the first batch out of the freezer, the exceptional taste is still in the 5-7 days out of the freezer, but by the time I get to the last freezer batch (usually a month or so) the exceptional window has disappeared. I've wondered whether that's because I'm just used to it and need a change or whether it really has staled enough in the freezer to achieve this.

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#6: Post by yakster »

I roast at least two 700 gram batches in my Bullet and I often roast a darker roast to drink in the near term and a lighter roast to start drinking later. I'll pick the type of coffees I think will work better for darker and lighter roasts, and if I'm running low on coffee I'll start drinking the darker roast right away, otherwise it'll usually rest for three days. I usually end up roasting every two weeks or so, I'll do more batches if I won't be able to roast on my normal cadence. This has been working well for me, I'm doing the darker roast first thinking that the Bullet will be more fully heated when I start roasting lighter.

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#7: Post by Marcelnl »

I recently had a, surprisingly, great ristretto in a restaurant after a good meal, and that rekindled a want for dark roast so I'll be trying to make some trying to use the profile shown. I take it gas is cranked open open again after the steady decline of delta BT?
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#8: Post by Milligan »

Thank you for the topic. Rao seems to be talking about all coffees roasted on a gas drum roaster starting from just past underdeveloped through dark roast only needing 1-2 days post roast. He doesn't specify exactly what the target is for all but dark roast (rancid after a few days in his opinion.) Drinkable? Peak? Off gassed enough to pull a consistent shot?

I feel like most of the coffees I roast on my Cormorant are rested enough to brew via filter within 1-2 days with espresso taking 3-5 days. I don't roast very light (90-100 Agtron gourmet is where I like filter the most) so I can't speak to the folks needing 3-4 weeks of rest for their coffee to open up.

I'm intrigued with the rising RoR post first crack. I've been exploring methods for dark roast and find dark roast more challenging than light roast. I've been having good results with Hoo's dark roast method of a long Maillard, high airflow throughout and a ~4min development. This seems to highlight the caramelization and chocolate that darker roasts are cherished for while minimizing the smoke and roasty flavor. I've had some great luck with deeply fruited coffees carrying the fruit note through the longer roast into a mellow pie-like profile. I typically roast where oil shows on the bean within a few days but does not coat it. Most are espresso stable a few days post roast.

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#9: Post by Milligan »

Marcelnl wrote:I recently had a, surprisingly, great ristretto in a restaurant after a good meal, and that rekindled a want for dark roast so I'll be trying to make some trying to use the profile shown. I take it gas is cranked open open again after the steady decline of delta BT?
Likely not, if the gas/power is held consistent from the start of first crack then you get the slight dip during first crack and a steady march back up after first crack starts to wane. This is typically where gas is reduced to continue a declining RoR but if you hold or do not reduce as much you get an increase again. This doesn't take into account a gas dip if that is needed.

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#10: Post by Pressino »

I've also found that a day or two of "rest" after roasting suffices for filter coffee and 3 to 5 days for most espresso, with one notable exception...which is Yemeni coffee. For some reason that coffee requires a longer period of rest. I've had some Yemeni beans that take more than two weeks to reach their peak. I'm not sure why this should be, but that has been my experience.