Thanks for posting a profile Gary. Interestingly, it's extremely similar to what I came up with based on Neal's writing on HB. Here is an example using a wet hulled Sumatran on the Cormorant. Aiming at 50F past FC, just in to SC.



By way of comparison, here is a dark-ish roast with a declining gas profile (40F past FC, around full city). This one has room to get a bit darker, but probably not in to second crack. I've found that the limitation is how hot I can charge and how high my initial gas setting can be. Even short of tipping and scorching, I've found that going too fast in the early part of the roast can introduce some harshness into the coffee.



For rest, I was pulling some espresso with these after 4 days, but found them much better after a week. For brewed coffee, I agree that they should be fine within a couple of day. Don't agree that they would be stale so fast though, I would consider them to be good drinking for a couple of weeks at least.

Which profile do you prefer for your darker coffees? I haven't given Neal's method a try yet and am curious. I would have though increasing RoR like that at the end would introduce harsh flavors but perhaps that thought is incorrect. I'll need to check out the other thread.

I went with a very shallow decline in ROR until yellow and then aimed for flat through the end of the roast. I have had the most success with this approach but I am just playing around and mostly roast this style for F&F.

The roast below was my favorite. Similar to Shotclock's experience, the declining ROR all of the way through was harsher to my tastes. I was surprised by the fruit that was still present in the cup.



I guess I will have to try out the climbing ROR at the end.

My profile preference for darker roasts is not totally clear. I've found that I prefer wet hulled coffee significantly darker - mostly to mute the "agricultural" notes that can creep in to these coffees. I haven't managed to get these dark enough without the increase in gas at the end. This may be that I'm just not a fan of these coffees... It is quite possible that I'm just not doing a good job with this technique, so I am very open to any and all suggestions.

Brazil, Mexico and Guatemala - I have tried all fairly dark compared to my normal roasting, and found that they do well with 35-40F past FC, which doesn't require an increase in gas at the end. These origins at this level (at least for me) make great chocolate bomb espresso with subtle acidity. I've found that going darker with these origin by using the gas increase looses some sweetness and acidity, and can introduce some harshness and smokiness. The increased bitter notes can be quite nice at times, but often I prefer the balance in a slightly lighter roast. My own personal preference for espresso is often a bit lighter (closer to 20-25F post FC, what I would call medium-light), but it seems that even this roast level (I do not consider myself a very light roast espresso aficionado) can be too much acidity for many. Increased solubility of the darker roasts also helps with more reliable pulls and less sensitivity to puck prep.

The question that I have not really resolved with increasing the gas at the end of the roast is how aggressive can I be? It seems too much gas introduces some nasty roastyness, not just dark chocolate, molasses etc. Not enough would either bake or flick the roast.

I thought this discussion sounded familiar... Roasting dark: 'S' curve vs constant declining RoR?

This is an excellent conversation, and very timely for me. I've only ever roasted up to, and maybe into the first snaps of, second crack for the vast majority of the time I've been home roasting. I would really like to explore dark roast, but the realm beyond SCs feels completely unknown and foreign to me. So all the info posted already is great, but I would like to pose some questions.

-What bean qualities do you look for when shopping for green that will make a good dark roast?
-Any origins or processing methods in particular that you like?
-I'll take some guidance from the graphs posted already, but is there a particular amount of time/temp development past SCs that is a good place to start for developing a dark roast?
-The few times I've tried roasting dark, I get somewhat mixed results. Sometimes it's dark and roasty, and quite pleasant, but sometimes I get a very noticeably "ashy" flavor that tastes straight out of an ashtray, and those roasts are almost undrinkable. I don't know if this comes down to bean selection or profiling (or god forbid, that's what it's supposed to taste like), but again, any thoughts or guidance are appreciated.

The above questions apply for coffee I'd be drinking as both pourover and espresso.

I have moved away from intentionally increasing ror for dark roasts.
Last 6 months or so have increased drum rpm from stock 62 to 82-84. This has made it much easier to roast full size batches 1.2kg green (1kg out) on 1.2kg Proaster.

Can post some Artisan pics in a couple of days when im at roaster laptop.
Faster spinning drum makes it easier to keep environment temp around 250C while charging at a much hotter BT without any scorching issues.

Im hitting full yellow at 5:00 (155-157C) then 4:00 - 4:30 first crack (191C) and another 4:00 - 4:30 end phase. 2nd crack starts around 23C post first crack.

I have found that just leading up to 2nd crack start 209 - 212 to be a really sweet chocolate caramelised with great aroma - classic comfort roast still with some acidity. Once 2nd crack starts, I need to go 15 - 30 sec into 2nd crack where it starts rolling and this seems to avoid off / funky roast flavours. Pretty sure anotherjim has mentioned this many times in the past and its something my own experience agrees with - dropping around the very cusp / start of 2nd is not great.

Similarly, i think Almico has found there is like a "no mans land" in roasting. For me with full batch size, that is anything less than around the aforementioned 4:00 mark in the final phase leading up to 2nd crack, around 209 - 210C and 15.8% weight loss. 15.8 - 16.4% WL seems to be a good window.

Just for contrast, light roasts im using 50% capacity, 7:30 - 9:00 total, with a range of 11 - 13.5% weight loss. Anything after 13.5% tastes baked - or the famous "hole in donuts". The light roasts dropped around mid first crack with 11% WL really benefit from 2 weeks rest and stays stable for quite a while after. Airflow is just above neutral.

Resting period for darker roasts not into 2nd crack, these are pretty good around 10 days onwards and dont really develop much of a shine. Un-opened at 2 to 3 weeks for espresso is better and then freeze portions here. Roasts that are steadily eased into 2nd crack get a nice even sheen about them after 5 to 7 days and I know some people like to let age a bit longer. For me now, I can not really drink stuff into 2nd crack, i still taste it though.

Ror for the dark roasts is mostly linear, perhaps with a very slight trend downwards, but its not something i shoot for. Its more about time at certain temps and progressing through that time in a very stable roasting environment. I make gas adjustment at full yellow (155-157C), then another adjustment around start of caramelisation (178 - 180C). This often takes me through to the end of the roast if I get setup right, sometimes needs very slight adjustment near end of first crack. Its been my experience that these roasts with minimal gas adjustments at the right times, produce much better flavour outcomes across the board.