(Charging) Dropping in Hot ???

[hankua]

I paid a visit to [creative nickname] recently (Mark) to see his USRC one pounder. He was telling me about the roast and learn
on HB, where they were dropping in hot and ending the roast with very little post crack development time; on a DP Ethiopian.

I think Mark was able to do an 8 minute roast with 1st crack @ 6:30. 

And it worked?

 I believe this theory came from Marshall Hance of Mountain Air Roasting. Marshall has a lot of unusual ideas about roasting, kind of makes you think sometimes. He's using a fluid bed roaster which operates differently than our drum machines as well.

The theory being you can pour any amount of heat while the coffee is in the green stage without scorching. By adding more heat in the beginning the roast can be ended earlier without underdevelopment. More heat can reach the center of the coffee bean.

So lets try this out and I did. Charging at 250c with the heat on 4kpa; that's pretty much wide open gas. At 160c started tapering down the gas, 200c 1st crack with the ROR too high. 1:30 post 1st crack development time 218c drop temp. I ran 5 roasts this way and each time the ROR was not really in control; so maybe the heat needs to be tapered down earlier. I was worried the coffee would be underdeveloped on the first day; second day it was OK. (my normal charge temp is 200c and gas on .5kpa)

Has anyone else tried this out?

[Gregr]

By adding more heat in the beginning the roast can be ended earlier without underdevelopment. More heat can reach the center of the coffee bean.

That's the part that I have a hard time wrapping my head around, especially given that recent Matt Perger article (http://baristahustle.com/lets-talk-about-roasting/). But the proof is in the pudding. After a few days rest was how was the sweetness, body and acidity hitting you? First though- were you or Mark pulling shots with these roasts or just coffee? Another thought is how would this work with soft beans- do you know if he uses the same approach with Sumatras?

[9Sbeans]

I am aware of this style for at least couple years.  There were several successful roasting contestants applied this approach.  You will need slightly higher than usual airflow from the onset of the roast, and start tapering the heat 10~15F before entering the first crack.   

It is said that beans roasted with this style will peak and decay faster.  I guess it won’t work on soft beans, but haven’t tried. 

Perger’s claim is not the same as Rao’s.  I’m inclining to Rao’s as of now. 

[Gregr]

What is Rao saying that's different about the roast up to the 300F/yellow point?

[9Sbeans]

In Perger’s article, he only focused on the post-1st crack part.

Rao stated “three rules”:
1. Apply adequate energy at the beginning of a roast
2. The bean temperature progression should always decelerate
3. First crack should begin at 75% to 80% of total roast time

To achieve Rao’s rule, Marshall suggests charging hot and only remove heat during a roast.  Charging hot and applying high heat can easily induce a very high RoR prior to 300F/yellow point without scorching.  To the extreme, Mark [creative nickname] did a very fast roast, and it was successful.

Imho, this is one of many possible approaches to follow Rao’s rules, but not the only one way.  Therefore, I posted several profiles, varying charge temperatures & applied heat before 300F, trying to make all of them obeying Rao’s rules.   

[jyalpert]

I did an ultra-short roast on that March R&L Yirg on Friday.  6:30 total roast time, 1Cs at around 5:15.  Sadly, I forgot to save the graph in Artisan.

The beans do not look tipped or scorched; I  charged hot and had the flame full open with high air to start, and backed off steadily as the roast went on.  Targeted TP @ 1:35 @ 280F, then ~35-40deg/min RoR from TP to dry, and then ~25-30 deg/min RoR from dry to 1Cs (#s were calculated roughly from the creative nickname post on HB).  Hit the brakes around 370F, and closed the shutters to start 1C (I use the perforated drum).  Pretty much just backed the heat and fan off as I went, with the most dramatic drop in gas and fan at turning point (gas to 2.5-3kpa, fan stepping down from 60-50-40-35V).

It smells nice, but we'll see how it tastes tomorrow.  I've been curious about this roasting style for a while now, since some of my favorite 3rd wave-style roasts I did in my old popcorn popper, which was giving about a 5-7min total roast time.

[Gregr]

Thanks for the explanation. I'm gonna give it a try with this natural processed Guatemala that I've been roasting lately. It's a good choice for me since I've already roasted a bunch of it for comparison.

[VS]

For those that have Mr. Rao's book, take a look at page 33 "Development Time." I feel it is an overlooked section.

He explains that you can achieve proper inner development by stretching the last phase of the roast, but this method is prone to flat, baked flavors. Instead, he suggests to apply higher heat early and shorten the last stage of the roast. Both methods will produce proper inner development.

I have come to agree with him. I noticed that my roasts with "development stage" over 2 minutes (regardless of roast level) bake the beans pretty flat. I advocate dropping at higher temps (450-520F), reaching 300F at 4-5 min, FC at around 8 min, drop 9:30 - 11 min.

Just my two cents for what its worth.

[hankua]

I did an ultra-short roast on that March R&L Yirg on Friday.  6:30 total roast time, 1Cs at around 5:15.  Sadly, I forgot to save the graph in Artisan.

The beans do not look tipped or scorched; I  charged hot and had the flame full open with high air to start, and backed off steadily as the roast went on.  Targeted TP @ 1:35 @ 280F, then ~35-40deg/min RoR from TP to dry, and then ~25-30 deg/min RoR from dry to 1Cs (#s were calculated roughly from the creative nickname post on HB).  Hit the brakes around 370F, and closed the shutters to start 1C (I use the perforated drum).  Pretty much just backed the heat and fan off as I went, with the most dramatic drop in gas and fan at turning point (gas to 2.5-3kpa, fan stepping down from 60-50-40-35V).

It smells nice, but we'll see how it tastes tomorrow.  I've been curious about this roasting style for a while now, since some of my favorite 3rd wave-style roasts I did in my old popcorn popper, which was giving about a 5-7min total roast time.

I believe this was the same bean Mark was using; same general profile. My point being this approach is quite opposite from the conventional "Boot Coffee" sensory roasting methods. 4-5 minute drying time, ramp to 1st crack, then roast development stage for 2:00 plus minutes. This is a tried and true method of roasting; and the final taste profile mix of origin/roast flavors can be manipulated. But if you end the roast too early before 1st crack ends, underdevelopment can occur.

Marshall Hance is a professional roaster with all the tools necessary to check out experimental roasting. EK43, VST lab meter, GS3 espresso machine, and wholesale customers providing feedback on his roasts. His theories about development seem quixotic at times and make one thing about the process.

One of the statements Marshall and Dustin have both said is the "turning point" where the BT stops declining and starts to rise is an irreverent landmark. Another one is "your thermocouple is too thick" and the data it sends out is inaccurate.

Funny thing is "home roasting" has turned into something other than it's name; where professional roasters are participating and lurking on hobbyist coffee forums. The level of discussion has morphed from what it was, just several years ago.

[Gregr]

VS- the times of the first two stages are pretty much exactly what I do but with a charge temp of only 420F. For quite a while now (for dense bean SO espresso) I've been doing that and finishing with 3:15-3:45 development-- like in the attached profile, with (usually) rich, intense, syrupy (sometimes) sweet results. Development times as long as 4:30 can still be achieved without baking so that leaves me to the thought that these guys are just recommending approaches that are aimed more for those with electric roasters that can't turn on a dime like the big professional roasters (and the Huky) can.

[akiley]

VS- the times of the first two stages are pretty much exactly what I do but with a charge temp of only 420F. For quite a while now (for dense bean SO espresso) I've been doing that and finishing with 3:15-3:45 development-- like in the attached profile, with (usually) rich, intense, syrupy (sometimes) sweet results. Development times as long as 4:30 can still be achieved without baking so that leaves me to the thought that these guys are just recommending approaches that are aimed more for those with electric roasters that can't turn on a dime like the big professional roasters (and the Huky) can.

It seems for us Huky roasters, that charge temp isn't very meaningful without noting charge weight.  I've been only roasting 350g loads.  Seems charging this hot would be a bit much.

[Gregr]

Got pretty close- first crack at 6:20.
I looked at this as a way to broaden my horizons and to see if the roaster was really as flexible as I'm always claiming. It is
One pound of Guatamala Santa Isabel Natural Process beans, solid drum, fast motor.
Charge at 465F, stove at 3.25kPa, fan at 30%.
At 300F fan up to 60% for 25 seconds then back to 30, stove still at 3.25.
At about 320F stove up to 3.75kPa (max on my gauge), fan still at 30.
At 360F stove to 1.0kPa, fan still at 30.
First crack at 387F/6:20, no change on stove or fan.
First crack end at 7:50, no change.
Drop at 8:20/419F.
I'll report back in a couple days on how it compares to the other roasts I've done with this same coffee.

[jyalpert]

One of the statements Marshall and Dustin have both said is the "turning point" where the BT stops declining and starts to rise is an irreverent landmark. Another one is "your thermocouple is too thick" and the data it sends out is inaccurate.

Totally agree.  If you actually had little probes on the beans, you'd see the curve coming up from room temp to wherever TP is as the probe and beans equalize.  For me, TP is indicative only of how much heat I've put in early on.  I need my TP to be consistent so I can plan the roast - for instance, I know if i have heat on full and fan at 60, I'll get TP at 1:35 or so, at a temperature correlated to my charge temp.  Then I can progress the roast from there.  I'd say TP is only important in that you need to know when it will come, and at what temp, since it serves at the jumping-off point for the rest of your roast.  It's also important to know when it will hit, since you're essentially flying blind before then.  It's irrelevant from roaster to roaster, and silly to try and compare, but it seems to me it's useful data for an individual.

Anyway, yeah I was pretty much trying to copy creative nickname's roast, more as an experiment than anything else.  My best results on my Huky have come from declining RoR roasts with FC at around 7:00-8:30, with around 20% development time ratios.  So this was a departure, but a fun one!  I feel like I have enough control over the machine now to mess around a bit.

[hankua]

Totally agree on TP, it's the beginning of the race to finish and charge temperature/gas settings determines where it bottoms out.

[Gregr]

Took a photo of this fast roast and if you look closely there are a few places where there are a few dark-ish divots that maybe are just short of turning into little round burnholes.
Edit- replaced the first pic with a crop and circles that mark spots that show what I'm talking about. Dropping the beans right after first crack finishes probably makes this a moot point but good to know that with the fast and furious roasting technique I need to end it very shortly after first crack finishes.