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Americano with lighter roast.
BenKeith
Many times I use my espresso machine to make a cup off coffee. Over the past few years, I've gotten lighter than ever on my roast, stopping many just at the end of the first crack. I learned real quick, light roast and a Livia 90 set at 9.2bar brew pressure don't go together very well. It's was extremely difficult to almost impossible to get anything close to even extractions and without little squirters . I use 18-18.5 grams in a 18 gram VST basket and to get any kind of extraction, I was having to grind way finer and tamping harder.
I was noticing the lighter roast still had a lot of chaff and figured this was probably my problem so I started using my hand grinder set with a huge gap between the burrs and doing a quick grind to break the beans up into fairly large chunks. Then I would dump them in a bowl and blow the chaff away before dumping them in my espresso grinder. Doing this, I had to open my espresso grinder up several numbers to get an extraction and they are very consistent and use a fairly light tamp. The tamp I use has a shoulder that stops on top of the basket to ensure it's exactly level so I don't tamp a certain pressure every time.
So, if you are like me and trying to use lighter roast in your espresso machine and having problems getting good extractions, might want to look at a course grind and get the chaff out before grinding. I've been doing this about a year or more now and is the only way I try to extract lighter roast.
This process also makes the darker roast extract better, but it's a pain in the butt to do when don't really have enough chaff to create a problem, which rarely do my darker roast have much chaff.
ChicagoJohn

Quote

BenKeith wrote:

to get any kind of extraction, I was having to grind way finer and tamping harder.


We're just getting into espresso and I'll be able to use your info. Thanks!

I have been roasting until just after 1C for use in my Aeropress and then my pour-over paperless cone. When I tried this product using the same grinder setting I'd optimized for both the Starbucks espresso roast my wife had been using and for some Lavazza Super Creme that came with our espresso machine and grinder, virtually nothing came through the portafilter basket for like 20 seconds and then only drips. I had to go way coarser to get it pull a double in 25-30 seconds with all other factors "the same". The Starbucks was much darker and friable and the Lavazza was in between.

So I was confused in reading your post since, if I'm understanding it correctly, it sounds like you are saying you had to do just the reverse. As I say, we are new to the espresso method so any light you could shed on this would be appreciated.

My second question is regarding what I would regard as an almost "grassy" flavor (I'm now sure how to describe it) that comes with the lighter roast which we don't find in the two commercial espresso roasts, both of which are darker and I would assume at least started into 2C. I would describe what I'm tasting as probably coming from lower molecular weight aldehydes, ketones, etc. But the odd thing is that I don't notice this with the my Aeropress or immersion / cone filter brewing processes, both of which are using much larger particle size grinds.

If you have any thoughts on this, I'd appreciate hearing them. My plan is to experiment with darker roasts than I've been doing since I don't really like the flavor that I'm having a hard time describing.

I'll look into the chaff issue you brought up too.
Edited by JackH on 01/07/2017 5:44 PM
So many beans; so little time....
BenKeith
Other than Sumatran and a couple others that I will no longer buy, if it's grassy or earthy tasting I usually conclude that it was an undeveloped roast, stopped a few degrees too soon at the end of the first crack and I mean just that. By a few, I'm talking as little as little as two degrees.
Since I'm get about half deft, I have a hard time sometimes hearing those last few snaps in some coffee's so on a new coffee, I usually have to experiment to find the stopping point. I've recently been trying three Columbians from SM and my first roast with the first one, I stopped at 414 degrees, which works great with a Brazilian I've been roasting. I way overshot my flavors so, I tried another at 410 degrees and it was much better. The next one I stopped at 408 degrees and it was pretty darn good also. I just tried one a couple hours ago I roasted four days ago and dang glad I only tried a 150 gram roast. I stopped it at 406 degrees and it tasted like I had brewed hay. At the same time I did that 406 degree roast, I had another I stopped at 409 degrees and it was very good. So, I've found with these, 408-410 works, higher they have little flavor, lower and they are under developed.

Understand also, this is using a my POS fluid bed roaster, RoastLogger software and a TC4 I have spent many hours working on getting it so it has extremely exacting control of a roast. To the point I expect it to hit each set point to the degree within and couple of seconds, and it normally does.

Since my espresso grinder is so highly modified, I have nothing to compare it to other than the way I calibrated it. When I set up my scale/graduations on my setting indicator, I did it with a dial indicator, so each number larger is .001" larger than the previous number. So. 0 (zero) is the burrs rubbing and 10 is .010". My normal grind is approximately on 8 (this can vary between 7 and 9 but 8 is a fair average). When I was grinding my light beans directly, I was having to run it down to 5 and 6 and you could see a whole lot of those light colored chaff pieces in the grinds. Once I started removing the chaff by the first grind, I see almost no light specs and have to run my grind setting closer to 9 most of the time. Using the naked portafilter, the extractions are very uniform and no squirters. Something that was almost impossible to achieve before I started removing the chaff.

Like my grinder, my Livia 90 is also modified. I've made a new dispersal plate to replace that ungodly thick six hole OEM one with a much thinner 18 hole. The OEM one was so thick, an 18 gram VST basket wouldn't hold 18 grams without pressing against the screen. Now I can do 18.5 grams and still pass the nickel test (barely). The six holes tore up the top of the puck, the 18 holes leaves it nice a pretty, (both were drilled for the same flow rate).
OEM brew pressure was approx. 14 bar, I made a shim and set it at 9.2 bar. I also increased boiler pressure so after a 2oz super heat bleed off, I can get precisely a 202 degree extraction for 50 grams of water and 25 seconds (if I want to get that much). I usually do a 2:1 ratio

As for darker roast, I've gotten to where I can't stand many coffee's taken to the SC. I still take my espresso roast to almost SC because we do latte's and cappuccino's and the milk kills lighter roast, but other than that, I've gotten much lighter over the years.
Edited by BenKeith on 01/07/2017 5:41 PM
ChicagoJohn
Thanks so much for the very detailed reply to my questions even though they were not to the main point of your original post. As a neophyte to espresso, I must admit my inability to appreciate the nuances of everything you describe, but I'll definitely return to this information later once I understand a bit more about how this all works.

Your experience with the importance of careful temperature control at end of roast for lighter roasts is likely the cause of of the problem I described. The fact I don't notice it with my immersion / pour-over filter / Aeropress brewing versus espresso, is probably attributable to the higher water temperature in espresso (~200F v 175-180F for my filter methods) and also to the much finer particle size distribution and surface area with the espresso probably resulting in a greater degree of extraction.

I will definitely do some experiments next time I roast to make examples of several different endpoint temperatures and then check them with each of the two brewing methods to see if I can demonstrate what you've said. It certainly makes a lot of sense and will just mean I have to do my roasting a little differently to make sure the product can be used in both brewing systems without an objectionable result. (I would expect them to still be different though.)

As for the grinder, I'm using a stock Rancillio Rocky where we happen to find, coincidentally, that a setting of 8 (sometimes up or down one) works ideally for a double shot in terms of time; ideally, that is, according to the 25 second target I've read and videos I've seen of how the infusion should run out of the portafilter.

So, if I try to use the lighter grind I've been doing (a Yirgacheffe) at an 8 and tamp the same etc., nothing comes out for a long time -- dribbles out maybe one side at starting at 18-20 seconds, for example. I have to go to maybe 15 - 18 setting to get an equivalent rate to what I get from the purchased espresso roasts at an 8. I would presume that's a pretty significant difference given what operating between 7 and 9 can do to the pull time.

So my second question is still how come your experience seems to be the opposite. My hypothesis was that the darker "espresso" roasts that run at a grinder setting of 8, are more friable due to thermal degradation of morphology within the bean. I can actually break them with my fingers whereas I can't with my lighter roast. Initially that seemed counter-intuitive, however, in that I might expect a more friable bean to produce more fine particles than one with more integrity. But I suppose it would also be possible that for the lighter roast, when set closer the burrs may be sort of scraping the surfaces off to make a finer "dust" whereas the darker roasted beans may be fracturing more readily due to compressive failure rather than shear failure and thus producing bigger chunks.

But whatever explains it, it is definitely a repeatable and significant difference between the roast levels and requisite grinder settings, and more interestingly, a difference that seems to be in the opposite direction to the one you are describing.

Any ideas on that one? (I'll let you know how things work out on the underdevelopment idea as soon as it gets warm enough for me to roast again here in Chicagoland -- from our temperatures lately, that'll likely be a while....)

Thanks again for your initial reply.
So many beans; so little time....
BenKeith
You Starbucks coffee, in all likely hood, is going to be fairly stale and will never extract like your fresh roasted coffee. I've never bought an off the shelf coffee that didn't require a much finer grind than a fresh roasted. That's what got me into home roasting over 15 years ago. I bought the Alivia 90 with the intentions of my wife being able to make her a cappuccino (what an idiot idea that turned out to be). Anyway, it was very quickly I learned off the shelf coffee didn't work. I also happen to have a Rocky I bought shortly after getting the Alivia 90, just haven't used it for a while now. Buying off the shelf coffee I was running settings down as low as 6 on it. When I started roasting my own, I was running settings around 13. I would also venture to bet you get very little creama on to top of those low number grinds.

I also use an Aeropress most of the time and for that, I don't try to separate the extra chaff. That process is just used for the high pressure espresso extractions. I just grind it and dump it in, just the espresso extractions is all I grind twice. I also run 203-205 degree water when brewing with it. The only pour over coffee I brew is through my Bunn, which like everything else, is also very modified, but it also runs a 200 degree brew temp.
I know many of the pro's run those low temps but I'm not a pro and I like mine hot because I'm going to add milk and sugar, and that would cool it down too much. I also like the flavor of the hotter extractions. I seem to get more of the oils or something and not quite as much of the fruity/flower flavors.
ChicagoJohn
Thanks for that explanation. When I do my experiments, it'll be interesting to compare the fresh samples at different final profile temperatures with the two commercial products in terms of grind setting for similar pull times. I will also take note of crema differences. I guess the fresher roast would have more gas being released and so would give more crema than older roasted beans.

If I get the gist of what you're saying, I may find out that comparing apples-to-apples in terms of age of roast, I'll see the same thing you do and need to set the grinder finer for a lighter roast. We'll see... that's part of the fun of this.

Thanks again for sharing your experience.
So many beans; so little time....
Koffee Kosmo
A quick and rough explanation on the roast depth to temperature association

The lighter the roast - The hotter the water it can withstand also a lighter roast likes some steeping time

Reverse that with darker roasts

Lights roasts ( Past 1st crack but not reaching 2nd crack ) are most suitable to be used in pour over coffee methods

Medium roast are suitable for espresso machines
Roast to the golden triangle - first snaps of - 2nd crack - on 2nd crack - just past 2nd crack

This level of roast coincides with the temperature band an espresso machine set
If your machine is too cool you will taste Lemon or grass - if your machine is running to hot will taste burnt coffee
If your machine is set at the optimum temp for the golden triangle roast depth you will have a great cup of coffee
The temp range on espresso machines is generally set at 89Cel to 93Cel

Have fun but don't try to cheat the Temperature to Roast depth association

KK
I home roast and I like it. Designer of the KKTO
Roaster Build information
https://forum.hom...ad_id=1142

https://docs.goog...lide=id.i0
Blog - http://koffeekosm...gspot.com/

Bezzera Strega, Mazzer Robur Grinder, Pullman Tamper Convex,
(KKTO) Turbo Oven Home Roaster.
ChicagoJohn

Quote

Koffee Kosmo wrote:

Medium roast are suitable for espresso machines
Roast to the golden triangle - first snaps of - 2nd crack - on 2nd crack - just past 2nd crack


KK


This supports our very limited experience. In developing automated tracking of a preset roast profile, I had a few batches that accidentally exceeded my target, which stops after 1C and before 2C. But rather than toss those, I saved them and when we tried them in our new espresso machine, they ground at the same settings and had good flavor lacking the objectionable grassy elements associated with my lighter roast.
So many beans; so little time....
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