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Espresso roast profile comparison
ChicagoJohn
In Ben Keith's recent thread, Americano with lighter roast, being new to espresso, I asked about my observation that the roast profile I had been using for pour over / Aeropress, gave a distinct "grassy" flavor when used in espresso and it required a much courser grinder setting to get the same pull time.

Ben and Koffee Kosmo's replies, it seemed I'd have to roast to a little higher temperature and just into 2C. So we had a break in the Chicago weather today with 38?F this morning, and I was able to get in between rain events to do a trial. I made a new profile and roasted a batch to that. The previous and present profiles (red) along with the computer's results in tracking them (green and blue) is shown in the attached image. I had to terminate the new batch sooner than planned since 2C started at right around 400?F with my set up and thermocouple, and I turned off the heat just as it got to a "rolling" state.

Remembering that Ginny would say she didn't necessarily follow the standard waiting period rule after roasting, I decided to go for it (and will check it again in 3-4 days). I think the results verify Ben and Koffee Kosmo's suggestions very well. First, I didn't have to change the grinder setting at all and got equivalent results to what we've been seeing in pull time for some Lavazza Super Creme we've been going through (It came with the machine).

More importantly, the grassy, under-roasted flavor was gone. I now have a profile that works for espresso but I'll probably tweak it more since I am only doing 91 gm batches. What my wife and I both noticed, however, is that it is distinctly different from the darker "espresso roasts" we've been using in that they tend to be more "chocolaty" while the one I did today is "fruitier" and/or "nuttier". I'm not sure how to describe it, but it's definitely not as "chocolaty" yet still very good and interesting.

So I apologize for diverting Ben's original post regarding Americano and light roasts / chaff after grinding, but I really appreciate the comments Ben and Kosmo and am looking forward to doing more experiments along these lines.

(PS - Also, Ben had made a comment about creme, and I did notice increased creme thickness on this fresh roast, maybe about 25% or 50% thicker creme than the Lavazza whole bean roast we had been using.)

BBQ grill
ChicagoJohn attached the following image:
roast-comparison.jpg

So many beans; so little time....
snwcmpr
I have been under the impression that there is no such thing as an "Espresso Roast" per se. I do see that you mean something for YOUR espresso though.

And:

Quote

2C started at right around 400?F

That is, give or take 5? F, where 1C starts for me.

I never go to 2C anymore, so no help there.

Ken in NC
--------------
Backwoods Roaster
"I wish I could taste as well as I wish I could roast."

As Abraham Lincoln said "Do not trust everything you read on the internet".
BenKeith
I was not suggesting you roast into 2C. I personally almost never roast into 2C. When I do, it's usually by accident.
However, going by temps, I wondering if the 2C you are referring to is a typo. My setup usually has a rolling crack around 395F and I don't hit 2C until approx. 440 to 444 degrees, depending on the beans.

If find I get the grassy/earthy flavor if I stop too soon in the FC. For the Columbian beans I'm playing with right now, FC pretty much ends at 407F and if I stop it any sooner than that, I find those grassy flavors.

Playing with different extractions in my AeroPress, I also found out, you definitely DO NOT want to under extract under roasted coffee. I did a cup I knew was grossly under extracted for a starting point to test different extractions. Quinine would be considered sweet to what that stuff tasted like. It was literally almost like someone had poured turpentine in it and actually made your mouth sting. That was BAAADDDDD stuff. Also, all my extractions are done with 203 degree water.
On this Columbian, I have also changed my recipe and getting some pretty dang good coffee the last few times I made some. My favorite cup of choice for coffee is a 14oz Corelle Coordinates Porcelain. I fill it almost to the top, sip the first couple of ounces black to cup it. That gets it down enough to add my sugar and milk. I've been doing this for many years, and still don't care for black coffee. The process I've been using I'm really liking is 19 grams for fine ground #11 on my Virtuoso, and looks similar to a course espresso. I use the inverted method on the AeroPress and dump probably 180 grams of water in. Let it set 15 or so seconds until the large bubbles quit coming up and make six back and forth swipes with their stir stick, the finish filling it. Put the filter on, flip it over onto the cup and just enough pressure that I notice the plunger going down. I don't time it but it's probably 45 seconds or more. I finish filling the cup with hot water, stir and taste. Then sweeten.
The grind is finer than I've been using, and taking a little longer to push the plunger down, but the coffee is good.
snwcmpr
I go 1:30 usually 1:40 after the start of 1C. I really like it and the final temp varies way too much for me to say.
That said, I gave a guy, a very qualified guy, some of my coffee I thought was really good. He said it was "Underdeveloped". I do believe him, but we got no grassy taste at all. So, I now only really try to please myself, because I have lower standards and the inability to know when it's really good :)
In other words, I know my place in the food (coffee) chain.

I get different results in french press than Technivorm than Bialetti than pour over. But it's all better than most store coffee.
Exception:
Mountain Air Roasters in Asheville, NC. One of our (past) members.

Ken in NC
--------------
Backwoods Roaster
"I wish I could taste as well as I wish I could roast."

As Abraham Lincoln said "Do not trust everything you read on the internet".
ChicagoJohn

Quote

snwcmpr wrote:

I have been under the impression that there is no such thing as an "Espresso Roast" per se. I do see that you mean something for YOUR espresso though.

And:

Quote

2C started at right around 400?F

That is, give or take 5? F, where 1C starts for me.

I never go to 2C anymore, so no help there.

Ken in NC


Hi Ken -- It's my understanding too that, "espresso" is a brewing process, not a specific roast. However there are roasted products that are intended for espresso brewing and they are labeled that way. As you said, I was referring to the task of obtaining a roast that produces a result we like using our espresso machine and that is what the label "espresso" means in the graphic. I should have made that clearer not having the context of Ben Keith's other thread where I asked my questions.

As for 1C and 2C, for clarification, here are a few comments on what these mean to me at this admittedly early point in my learning curve. My use of these terms refers to specific audible events. I characterize 1C as loud, discrete cracks that begin one at a time and proceed to occur more frequently but they pretty much all sound similar. In my roasting process, there is an interval following 1C during which temperature continues to rise but there are no audible 1C sounds. I associate the phenomenon of 1C with sudden release of gasses and expansion of volume / reduction in density (to roughly half the bulk density of green beans), sort of akin to popping of popcorn, but different.

As temperature continues to increase, I start hearing evidence of another phenomenon -- a much more muffled "crackle" as opposed to the loud, individual pops of 1C. This, I believe, is indicative of a deterioration in the morphology inside beans which causes compressive strength to decline quickly. I think it's likely a form of thermal degradation and decomposition, qualitatively different from 1C transition.

I've found that for the specific equipemnt I use, a modified popcorn popper, these two phenomena begin and end repeatably within very narrow temperature ranges. However, for the same piece of equipment and similar time-temperature profile curves, I've noticed some relatively large shifts in these onset temperatures when I change the location of and / or the construction of the thermocouple. I assemble my own from thin-wire K junctions attempting to both shield the junction from direct exposure to chemicals in the roasting chamber (which can affect the junction over time) while also trying to minimize the heat capacity of the housing and maximize its thermal conductivity to minimize hysteresis and give a rapid response to momentary temperature changes in the RC. Its location also influences the measured temperature at 1C and 2C onset. Again, onset of both transitions are repeatable for a given arrangement but subject to change when thermocouple assembly and/or placement changes. Their significance in my situation is only with reference to roasts run with exactly the same equipment set up.

As long as ROR is not too rapid, I would think that for a given bean sample the 1C and 2C phenomena will typically both occur for various roasting processes; e.g., hot air versus drum and so on; and that because the thermocouples we use as an relative index of average bean temperature are not actually measuring the center of individual beans, fundamentally different process types will also have an effect upon 1C and 2C onset temperatures. For a given set-up and sample of greens, however, results should be repeatable from batch to batch.

The onset of 1C and 2C noted in the chart was determined by noting the temperatures when I heard these events for the set-up I'm currently using, and it has been repeatable to +/- 2-3?F for 1C. I've only hit 2C previous by accident. This time it was intentional. The 1C onset temperature shifted downward by about 20?F the last time I changed my thermocouple assembly and placement, but it's consistent and that's my main concern, not the actual value itself.

From a chemistry perspective, the kinds of thermal degradation I'm imagining taking place in 2C, promoted by breaking of carbon-carbon bonds, charring, etc., would normally take place at higher temperatures than where I report 2C; e.g., maybe in the region of 430-440?F / ~ 225?C. When I first started out, I had a different thermocouple arrangement and was actually getting temperature readings in that range. So I am pretty sure my current thermocouple arrangement is giving results consistently low, but again, as long as it's repeatable, it is fulfilling its purpose for me.
So many beans; so little time....
ChicagoJohn

Quote

BenKeith wrote:

I was not suggesting you roast into 2C. I personally almost never roast into 2C. When I do, it's usually by accident.
However, going by temps, I wondering if the 2C you are referring to is a typo. My setup usually has a rolling crack around 395F and I don't hit 2C until approx. 440 to 444 degrees, depending on the beans.


I wrote a lengthy explanation of the temperature issue in response to Ken's comments above, but I would think your temperatures are more in line with internal bean temperatures than mine are. I am just using mine as repeatable indicators or indices of the phenomena involved, not as measures of average thermal energy within the beans. So sorry for that confusion.

Like you, I never roast into 2C either except by accident, but I did it this time from suggestions of others, just barely getting to onset of 2C, so I could see if that eliminated the grassy flavors I get from the expresso machine (but not from my Aeropress or pourover method), and to investigate the effect on grind setting as well.

As I said, this change eliminated the grassy flavor and gave results similar to the commercial "espresso roasts" we have at the same grind setting.

For Aeropress I've always used significantly cooler water. They recommend 175?F, I did a series of experiments from there up to 210?F, and definitely preferred the cooler temperatures (180-185?C) because I was getting a sweeter, less bitter result that way. So since something must explain the marked flavor difference of the light roast I've been doing on the espresso machine versus Aeropress and pourover cone, I am guessing temperature is playing a major role, but other important differences include particle size and pressure.

If I were to try the very fine grind I'm using for espresso in the paperless pourover cone, I'm certain it would clog. And I have to think the same would likely be true in the Aeropress, but I think I'll actually try that to see if when I do it at 200?F I then get the grassy component. If so, that would indicate water temperture, and if not, maybe pressure. I'll try that tomorrow morning.

I'm trying to come to an understanding of what I'm observing, but at the same time I also want to come up with a roast profile that is optimized for our espresso machine so that I'll be able to use that brew method to explore single origin differences. Hopefully I'll be able to get that result by stopping just prior to 2C instead of having it start because, if for no other reason, in my mental model of 2C I associate it with thermal decomposition of the organics at a pretty fundamental level, unlike the changes taking place from heating prior to that point.

Thanks for all your comments -- they are very helpful in my thinking about this, and when I've made observations that may shed more light on all this, I'll be interested to hear your reactions.
So many beans; so little time....
BenKeith
Yes, you are right in that temps mean nothing outside the roaster they are being read in. I've seen professionals talking about 2nd cracks at 335F and I'm just coming out of the drying phase at that. If you are using a glass roast chamber and have good light on it, you can see when the beans are in or near the 2C stage. If you are not just pouring the heat to them and it's a gradual increase, you will see some beans just start to pick up that little sheen and will see the small droplets of oil start to ease out. When I first start seeing this, I know I'm as deep into the roast as I want to go, because I usually can't hear 2nd cracks. I have a hard time hearing the first in some beans.
I am surprised you are still getting that grassy flavor in beans that is not the norm for that dark of a roast. Other than the Sumatrans and a couple others, I don't normally get those earthy/grassy flavors once I've completely finished FC. Have you tried extending the drying phase about 30 seconds and see if that helps keep them from showing up? I usually want mine to be at 300f in exactly four minutes with most Central and South American beans, but on some of the other beans, I do have to adjust that.
I have said before, I only roast dark espresso (near or into SC) for the purpose of Latte's and Cappuccino's, where the milk pretty much wipes out the lighter roast.
I have and do roast beans for espresso, without the milk, and do taste/drink espresso's from time to time (even though I don't care to drink them, I actually prefer those over black coffee) so when we have company that wants an espresso, I know I can make them one that's drinkable. For those, most of the times it's a SO coffee and I roast to a level that actually makes a good cup of coffee also. I don't get anywhere near 2nd crack.
roast misconduct
I'm brand new at roasting with five roasts, so I can't really comment much on temps and profiles. I am, however, a home machine espresso head.

According to the internets the trend now is lighter roasts for espresso. The bite of a light roast shot to me is too much. IMO it's under roasted for espresso. For me personally, I still like dark roasts for shots. Not quite french black/charred like I used to like it but a very deep Vienna. Well into 2C. The shots are smoother, more chocolates and toasted caramels come out. Most other flavors are destroyed by the heat, you shouldn't have to worry about grassy flavors.

I roasted my first batch of Brazil DP three days ago and had my usual first, and then a second shot this morning. Excellent.

I did over shoot my target a little though, I would call it French Roast, not Starbucks French but pretty dark. Other single origin roasts I've done were just starting 2C, much lighter and were good but had a little too much bite for me. Really good in pour over though.

To me three days rest minimum on any espresso extraction. You'll get that bite, under roasted shot. To get a consistent extraction you need to adjust grind/tamp/dose over the course of a pound. It evens out after the about the fourth or fifth day.
Edited by roast misconduct on 01/10/2017 8:21 PM
ChicagoJohn

Quote

roast misconduct wrote:

....According to the internets the trend now is lighter roasts for espresso. The bite of a light roast shot to me is too much. IMO it's under roasted for espresso. For me personally, I still like dark roasts for shots. ....

.... Other single origin roasts I've done were just starting 2C, much lighter and were good but had a little too much bite for me. Really good in pour over though.

To me three days rest minimum on any espresso extraction. You'll get that bite, under roasted shot. To get a consistent extraction you need to adjust grind/tamp/dose over the course of a pound. It evens out after the about the fourth or fifth day.


I found this to be very helpful, being very new to espresso and also wanting to roast as light as possible to preserve single origin differences. My limited experience thus far would be congruent with your "just starting 2C" target. I also agree with the general three day rest rule based upon previous experiments; I only did the immediate initial test of the roast described in my previous post out of impatience -- I'll be checking it again in a few days.

One question I have for you is whether you could clarify what you mean by "bite". One possibility might be acidity. There are low molecular weight organic acids that form during roasting and which can either break down or vaporize if given sufficient time at that temperature. Also, I think maybe higher water temperatures during extraction / infusion may facilitate them dissolving. I guess another possibility might be bitterness, but I would generally associate that with over-extraction.

So if you could help me understand that better, it'd help me know what I should be looking for.

Thanks again for your comments. PS - do you add anything to your espresso? I generally have been in the habit of adding half-and-half to my pour over (which is really more like a french press soaking process that goes through a paperless cone), and my wife has been in the habit of adding H&H to her espresso shots and some drops of stevia for sweetness so I have been doing that too. I'm thinking that could dramatically alter things in terms of "bite", depending upon what you mean, and so I want to try to duplicate how you are adulterating the result, if at all.
So many beans; so little time....
roast misconduct
Yes, the bite I'm referring to is the acidic, bitter components that are normally very mild and desirable (brightness etc.) which other brew methods don't concentrate like an espresso extraction does.

Higher brew temps are said to result in a increased body and sweetness.

9.8 times out of 10 it's straight shots (double/triple) for me. I'm not a fan of warm milk. If I can hit the temp just right when I steam the milk I'm ok with a cappuccino. It doesn't happen often though.

Obviously some origins will generally be better at espresso than others. Holding up to darker roast levels, changing flavors at darker roasts, not get lost in milk etc. And ones within those may or may not be to your tastes. And then there will probably be things you like and things you don't like within the ones that are to your tastes.

This is where blends come in.
ChicagoJohn

Quote

roast misconduct wrote:

Yes, the bite I'm referring to is the acidic, bitter components that are normally very mild and desirable (brightness etc.) which other brew methods don't concentrate like an espresso extraction does.

Higher brew temps are said to result in a increased body and sweetness.

9.8 times out of 10 it's straight shots (double/triple) for me. I'm not a fan of warm milk. If I can hit the temp just right when I steam the milk I'm ok with a cappuccino. It doesn't happen often though.

Obviously some origins will generally be better at espresso than others. Holding up to darker roast levels, changing flavors at darker roasts, not get lost in milk etc. And ones within those may or may not be to your tastes. And then there will probably be things you like and things you don't like within the ones that are to your tastes.

This is where blends come in.


All of this is very helpful. I think I'll try drinking straight shots or at the very least tasting them before adding anything that covers things up. I've been stuck on a blend of Yirgacheffe and a Uganda green with my modified French press brewing / Aeropress, but I guess it's now time to start sampling single origins again. Exploring is always a fun part of it; probably why I decided to try espresso brewing recently. I'm really looking forward to it; thanks again for sharing your experience. ThumbsUp
So many beans; so little time....
roast misconduct
Here's a H-B guide to blending for espresso, it has some generalizations as to origin aspects among other things that you may find useful.
https://www.home-...nding.html

I plan on using a Dry Process Brazil for my base, it's super smooth and chocolaty with good body and crema. I do want some bite though, a short little shock is good to get the taste buds woke up. That's about as far as I've got, aside ordering some Aged Sumatra that I'm going to try with the Brazil.
ChicagoJohn

Quote

roast misconduct wrote:

Here's a H-B guide to blending for espresso, it has some generalizations as to origin aspects among other things that you may find useful.
https://www.home-...nding.html

I plan on using a Dry Process Brazil for my base, it's super smooth and chocolaty with good body and crema. I do want some bite though, a short little shock is good to get the taste buds woke up. That's about as far as I've got, aside ordering some Aged Sumatra that I'm going to try with the Brazil.


Thanks for the link! I'm going to start planning for when it warms up here in Chicagoland and I can get back to roasting again.
So many beans; so little time....
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