Is roasting darker about increased heat or longer time?

January 22nd, 2021, 11:31 pm

So as the title says if I want to roast darker for espresso and especially for milk drinks Is the best route to up my average temperature per minute and keep the overall profile looking about the same as my lighter roasts? Or should I roast as I do the lighter roasts but drop later at higher temp?

Also I haven't roasted to second crack in about 75 roasts, (103 total for me) but I honestly can't hear the bloody things popping lol. If I hit first at 375f, approx what temp can I expect second? I have been assuming their is about 40 degrees f delay?

Ive Been more than a little pleased with my lighter roasts through a V60, and it's pretty good as an espresso if a little too acidic for my taste. But being Italian everyone I know wants darker and stronger including the boss. (I assume they unknowingly mean Robusta flavours, I bought 5# of this to blend to test my theory. I'll mix with a Brazil)

This is a light roast Ethiopian Yirg I enjoyed for reference in my v60. The acidity while pleasant in a pour over is what kills it as espresso, and flavours get absolutely drowned in a cappuccino.

#2: Post by **GC7** » January 23rd, 2021, 8:29 am

I'm really interested in hearing what experienced roasters think about this as well. My definition of "dark" for my better half's flat whites is not what some of our friends would want but it is at the cusp of or just at second crack. My instincts say to draw out the roast (35% development) where as long as it's not stalled it will develop without baking. My instincts say too much heat and too fast after dry end and first crack will not develop all the flavors from the beans. I don't know, however, if my instincts are correct so I am interested in following this thread.

On my roaster, second crack is about 40* after first starts but frankly it's hard to hear things on the bullet.

Here is an example. It's a generic but excellent Brazil espresso base and Sumatra Mutu Batak. I blended this so it would be 40% brazil, 25% Sumatra Mutu Batak when 35% separately roasted light Ethiopian or medium roast Colombian was added to it. It has made some absolutely wonderful comfort flat whites. I guess the question is if the ROR decline should follow a shallower slope to get to the same drop temperature.

#3: Post by **Almico** » January 23rd, 2021, 8:58 am

Heat.

You can roast coffee for an hour at 220° and have almost raw coffee. You can burn it to a cinder in three minutes.

#4: Post by **edgndg** » January 23rd, 2021, 9:06 am

I'm on a Quest M3s. When I predictably want to go a couple snaps into 2d crack, I charge at a higher temp, use about 10% higher wattage at beginning of roast and throughout (eg more heat). My 2d is usually 35-40 degrees f after first. FWIW I mostly have a milk drink in the AM, and have been gradually roasting somewhat lighter (say City+) which has plenty of IMO more interesting flavor in my caps.

#5: Post by **GC7** » January 23rd, 2021, 9:06 am

Almico wrote:Heat.

You can roast coffee for an hour at 220° and have almost raw coffee. You can burn it to a cinder in three minutes.

Alan - I'm not sure what this means. 220* is heat. 500* is more heat.

What's the best way to get from A to B. A is your raw green bean and B is a bean at the cusp of second crack?

Thanks

January 23rd, 2021, 10:37 am

I've been trying to expand my roasting range also. I'm finding it quite challenging to roasts darker without defects. I've been trying to enter 1stC at higher ROR and dont cut the heat as much during the crack. The hard part is managing the hump, crash and flick.

This one turned out pretty well. It really made this coffee tasty compared to my usual drop right after 1stC finishes at around 20%.

Is roastiness on darker roasts a defect or just what happens when you roast darker? I get burnt/roasty flavors when I flick at the end. Are there darker roasts without burnt flavors?

#7: Post by **keno** » January 23rd, 2021, 1:16 pm

Vince, it really depends on what you want to accomplish. Roast level defined by color is a function of end temp and time. You can do a dark roast fairly quickly with a higher end temp or with a lower end temp but longer development time.

Check out this study which looks at the chemical and sensory differences in coffee all roasted to the same level (Agtron 76) using different profiles to get there: The Effect of Roast Development Time Modulations on the Sensory Profile and Chemical Composition of the Coffee Brew as Measured by NMR and DHS-GC-MS

Even though this represents a medium light roast I still think the take home message holds for somewhat darker roasts:

Jesper Alstrup wrote:Fast roasting favoured a chemical composition that offers a higher sensory perception of Fruitiness, Sweetness and Acidity in the cup. Longer development times led to a change in the chemical profile, providing a more Roasted, Nutty+Chocolate, and Bitter sensory perception

#8: Post by **Brewzologist** » January 23rd, 2021, 4:35 pm

I seldom go past 420F drop temp which is FCs+35F on my rig. For that to work versus a light roast of the same bean, I shoot for a slightly lower peak BT RoR followed by a shallower decline and enter FCs around 20-23 F/min. This usually works for well behaved beans. I'm too chicken to go further and don't bother since I like lighter 'dark' roasts anyway.

#9: Post by **EddyQ** » January 23rd, 2021, 5:07 pm

On the rare occasion I roast dark ( meaning into 2nd crack and beyond), I try to maintain a DTR of 24-26%. In order to do this, you must go into first crack with higher RoR. This tends to make crashes and flicks more challenging, but you are running out of options for controlling it.

#10: Post by **drgary** » January 23rd, 2021, 5:20 pm

This thread may help,

How to roast darker

especially this post within it.

N3Roaster wrote:I'd start by removing the constraint on declining rate and suggest not being afraid of cranking up the heat moving out of the range between first and second crack. Especially if you're planning to go substantially beyond the start of 2C, taking that part of the roast faster lets you get to the higher temperatures where the chemical changes you want out of a dark roast start while not spending so much time getting there that you completely destroy desirable flavors developed earlier in the roast.

The most popular roasting class I've been teaching lately has been one that explores lots of different profile shapes across a range of roasts, and my experience with that within the dark roast category is that what I've just described is preferred for dark roasts compared with the same coffee roasted to the same ending temperature following a strictly declining rate by almost all students in the class regardless of the coffee used for the exercise. If, after getting to that end point you want to try again to compare with what you've been trying to do, the experience from this different approach should give you a better sense of how much heat you need for that coffee in your machine going in and you can plot out a declining rate plan based on that which should make it easier to avoid premature stalling. Having that plan written down (or loaded into your data logger) will let you see where specifically you're deviating from the plan (if you're still having trouble), which makes it easier to troubleshoot those specific problematic points.