Chert wrote:Someone can have a chance to school a newbie here.

Comparing the graphs of posts #17 and #18, the intervals we have timed are quite similar to post #17 rgrosz and our charge temps vastly different.

Does that suggest that we have flawed data such as missing the true end of dry or 1Cs?

Many people do go above 400F, but I rarely use a charge temp greater than 325F (ET).

I doubt that there is much wrong with our determination of when 1st crack starts. More subjective to identify the end of 1st crack.

As mentioned in my notes for post #17, my thermocouples give lower than normal readings. I adjusted for this by telling artisan that DE is at 280F. I noticed that you have DE set at 340F - is this intentional?

rgrosz wrote: I noticed that you have DE set at 340F - is this intentional?

It is not. I know that the intervals can be set, but I did not adjust them. Not intentionally at least.

So I know I am late to the party this month; at first that was because I was travelling, but then later on it was because I was so surprised at my results that I had to perform multiple blind cuppings before I believed the evidence of my own senses. Suffice it to say that experimenting with following Marshall's recommendations as closely as I could has seriously upended what I thought I knew about roasting. I'm not yet ready to generalize this to all coffees and roast levels, but I will say that for a brewing-focused roast of this particular coffee, the Hance/Rao method is worth taking very seriously.

And just to apologize in advance, there is a lot of info in this post, so it is going to be a bit longer than usual.

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The first roast I will describe is the one the won the blind cuppings, hands-down, each time I did a comparison.

Roasting Info:

Bean: Yrgacheffe Gedeo Kochore ECX
Roaster: USRC Sample Roaster
Charge Mass: 350g
Charge Temp: 400F (much higher than what I typically do!)
Dry/Ramp/Development: 2:20/2:20/1:30 (!!!)
FC-start temp: 376F
Finish Temp: 401F
Overall Roast Time: 6:15 (!!!)
Moisture Loss: 13%

Profile Plot:



[BT=Red, Exhaust=Green, Gas=Blue, Fan=Yellow]

Cupping Notes:

Rest: 4 days
Brewer: v60
Grinder: Mini-Bunnzilla
Water: 204F, 250g
Coffee: 16.5g, fine grind

Dry Fragrance: Rich, cantelope & tomato jam, roasting spices, floral

Wet Aroma: Vanilla, milk-chocolate caramel, floral, citrus, cherry

Warm taste: Sweet caramel, meyer lemon/clementine, bergamot, lingering, richly fruited finish with just a hint of black tea astringency.

Cool cup: Lovely, like lemon-infused black tea w/ whole milk & sugar.

Overall Impression:Right now I'm drinking a siphon pot of this, and it is even better, as it bulks up the body a bit to balance the high note. Compared with my standard approach to this coffee, which followed a 4:30/2:45/2 and involved a cooler start, followed by increasing heat before and during ramp and then slowing things down with low gas and high airflow to slow down development, this cup had better florality, acidity, and sweetness, without any perceptible reduction in body. Nor was there any scorching evident, either visually or in the cup.

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I was astonished by this result, as I had thought I had taken the recommendations too far, resulting in a roast with a drying time so short that I was sure it would taste terrible. After all, I had always taken it as an article of faith that, with the exception of some coffees with unusually pleasant savory notes, most wet-processed coffees taste best with a drying interval in the 4:00 range, a faster, hotter ramp, and a typical, city-roast development interval between 2:00 and 2:30 in length.

For comparison, here are the other two profiles, which cupped out pretty similarly to one another, both of which fell a few points behind the one I describe in detail above:

This first one would be my standard approach to a high-quality washed Yirg, gleaned from readings on HB and the Shrub, as well as my own trial and error, following a 4:30/2:45/2 profile:



And this was a more drawn out version of a profile following Marshall's interpretations of Rao's rules, resulting in a 3:30/4:45/2:15 profile:



You might notice that both of these involved a slight uptick in ROR following the end of FC. I noticed that both were, by comparison to the faster profile with less of an uptick, a bit more astringent, which may be how I interpret the "papery/cardboardy taste" that Rao described as a defect when ROR increases. They also had a lower finish temperature, due to entering FCs at a lower velocity, but this resulted in less, rather than more, acidity in the cup.

I'm ordering more of this so I can keep playing along next month. I think I will next try a comparison of the "fast Rao" profile I liked best with one that is just a bit slower, perhaps in the neighborhood of 3/3/1:45.

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TL;DR: A very fast profile, lasting 6:15 overall, and involving fairly constant heat input with moderate airflow, beat the pants off of two other approaches, one of which was pretty close to my standard, cooler-start, 4/3/2 approach to washed coffees, and the other of which was a more gradual Rao-style profile.

[creative nickname] wrote:Brewer: v60
Grinder: Mini-Bunnzilla
Water: 204F, 250g
Coffee: 16.5g, fine grind

I'd be curious about results brewing the longer roasts in the same fashion with a more coarse grind, if you have beans and time

Sure, I'll give that a try. Those are my standard brewing parameters for city roasts. For what it is worth, I varied both grind size and temperature for my head-to-head cuppings, in case level of extraction was making a difference, and (to my surprise) preferred the "fast Rao" roast under all conditions.

Hey Mark. Thanks for a very interesting post. My experiences lately have me pretty convinced as well. I've bumped up my charge temps beyond what I thought reasonable and been having great results.

I'd be curious what your approach to airflow is for your Rao profile. I'd also be curious how you're approach heat input. Of course, your roaster has way more thermal mass than mine, so things won't generalize perfectly.

It's interesting to think about the relationship between ideal airflow and roast speed. The Nords, who roast very fast, tend to use a ton of air. In the US, third wave roasters tend to be a bit slower and use less air. I've noticed that my faster roasts may do better with a bit more air, and specifically more air early, since bean surface burning is more of a concern. There's an interaction between airflow and aroma (that is, more airflow tends to mean less aroma), but if you roast faster, you minimize this problem.

NoStream wrote:I'd be curious what your approach to airflow is for your Rao profile. I'd also be curious how you're approach heat input. Of course, your roaster has way more thermal mass than mine, so things won't generalize perfectly.

The airflow, based on Marshall's advice, was held constant and steady throughout, at a moderate setting (about 50% of max power to the fan). This is more than I would have used in my past approach during drying and ramp, and a bit less than I would have used during the later stages of development.

I've been doing similar and been surprised how well it's worked. When you're adjusting airflow all the time, you're adjusting the convection/conduction ratio, which can potentially wind up affecting the RoR in unexpected ways. I've expected more roastiness to show up, but that hasn't really been the case, at as far as using less airflow in ramp.

[creative nickname] wrote:Sure, I'll give that a try. Those are my standard brewing parameters for city roasts. For what it is worth, I varied both grind size and temperature for my head-to-head cuppings, in case level of extraction was making a difference, and (to my surprise) preferred the "fast Rao" roast under all conditions.

I was using grind settings on the finer side with lighter roasts until I received some really well developed light roasts and found them over-extracted and dry, just after reading the 4th Barista Hustle. I did many tastings at multiple grind sizes and found I liked the results of increased grind size quite a bit (as long as it's well developed). Ultimately, I kept dosing the same and found the sweetest, cleanest, most syrupy coffee I've experienced.

I'm working out how to get that level of development in my roasts and have found all the beans I've been roasting for months showing better than ever. Exciting epiphany.

[creative nickname]

Those results are crazy...ordered a nice supply of this coffee to experiment and learn...I roasted some other washed ethiopian to a 3.30 3.30 1.40 profile and was pleasantly surprised with the results...Caught a cold so couldn't taste as the coffee aged a little...I'll be testing this a lot more.