Is it a roast issue or a green issue? (Prospective new roasters; you should read this too!) - Page 10

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
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luca (original poster)
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#91: Post by luca (original poster) »

mkane wrote:Is there a delivery problem from where you're at? I mean, does everyone, in your neck of the woods have an issue with green coffee not being up to standard?
There are tonnes of problems with buying green in Australia.

For starters, it's traded in USD and our dollar has been low against the USD for a while. We're very far from everywhere and I gather that a lot of our shipping isn't direct.

I'm told that our coffee roasters are price sensitive. But, equally, our home roasters seem to be pretty price sensitive; a lot of them seem to want to pay less on a retail, small purchase basis, than coffee roasters might pay on a wholesale, whole bag/whole pallet basis. Plus the market seems to be slanted towards

Domestic shipping-wise, yeah, Australia is massive; sort of in the order of the size of the USA, but we only have something like 1/17 of the population, so things have to ship long distances. But that's not so much of an issue; it's probably more the international shipping that's the issue. We usually get new crop coffees popping up in our roasters here a few months after they pop up overseas, but, having said that, last year was hard for everyone with the suez canal wedge.

Our market is small, so we just don't have a very competitive green coffee market for home roasters. There are a few dominant suppliers and then a few that have stuff as a sideline.

But what I don't know is what coffee is like elsewhere. There's tonnes of bad green on the commercial market that people rave about, and people rave about the green on the home roast market. Even the visibly insect damaged and mouldy green has its rabid defenders. But is this any different outside of Australia? I kind of never know what to believe. It sort of seems like as soon as any information makes it to the internet, someone will turn it to an assertion about quality in their favour. Like I've pointed out for a while that castillo is often astringent. I just read a promo from a roaster saying that they've got a particular castillo and it bucks the trend and is not astringent. I have that exact coffee and it is astringent. So ... I don't know? It wouldn't surprise me if there's better quality green available to home roasters in the USA than in Australia, owing to your many advantages over us. Equally, I'd be surprised if it's as good as everyone's promo and marketing material makes it seem.
LMWDP #034 | 2011: Q Exam, WBrC #3, Aus Cup Tasting #1 | Insta: @lucacoffeenotes

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luca (original poster)
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#92: Post by luca (original poster) »

OldmatefromOZ wrote:Hmm that's interesting, i had either forgotten this or failed to interpret originally. I would be interested to know the reasons for this design choice.
We can probably ask if you're really interested, but if I had to guess, I would guess that it's not necessarily as a result of an extended test of hundreds of different options; it's probably more that it's cheap and easy to do, and does seem to be useful. I mean if you're going to take the temperature anywhere on the drum, the part that has the most contact seems like the logical part. I imagine that the drum temp could vary quite a bit around it. I guess it wouldn't surprise me if they did something like taping a dozen probes to the drum and taking readings with a multimeter to work out what looked useful. Also a bit of a question as to how thermally isolated the roasting chamber is from the rest of the machine; I think that it's connected to other metal parts in the frame.
LMWDP #034 | 2011: Q Exam, WBrC #3, Aus Cup Tasting #1 | Insta: @lucacoffeenotes

Lwowiak

#93: Post by Lwowiak »

OldmatefromOZ wrote:Hey Luca,
Maybe veering off topic here...
Re cap on above mentioned technique:
Just under max airflow
Find optimal burner output for that airflow which gives desired roast time with optimal batch size = brings out the quality acidity fruit, clean and nuanced cup.
(Around 50% with gas drum)

Because of much larger drum mass, my charge temp needs to be slightly higher than target temp. Joe Morocco's +/- 6 degrees Celsius of target temp seems to be a good guide.

With the stablised environment its a matter of running this optimal hot air stream until just before or around the start of browning / caramelisatiion. Less mass the longer you may need to hold on / or smaller gradual changes.

For my roaster in Celsius
Starting to yellow 150
Full yellow 155 - 57
Orange 163 - 165
Start brown 172 - 175 (at 50% capacity this is where first gas adjustment is made and ROR has magically declined on its own! If gas left alone this is where ROR will start to plateau and or incline slightly before first crack, resulting in explosive crack / crash / stall / bake / flick etc.)
First crack 187 - 191
50 sec to 1:15 development
Thank you for posting this. I have a 1.5kg gas drum roaster and this is quite relevant to my situation.Slightly different BT readings, but close enough and most likely due to type of probe and placement. I roast at 50% for filter and will give this a go as I have made gas adjustments earlier than what you posted.

OldmatefromOZ

#94: Post by OldmatefromOZ »

luca wrote:We can probably ask if you're really interested, but if I had to guess, I would guess that it's not necessarily as a result of an extended test of hundreds of different options; it's probably more that it's cheap and easy to do, and does seem to be useful. I mean if you're going to take the temperature anywhere on the drum, the part that has the most contact seems like the logical part. I imagine that the drum temp could vary quite a bit around it. I guess it wouldn't surprise me if they did something like taping a dozen probes to the drum and taking readings with a multimeter to work out what looked useful. Also a bit of a question as to how thermally isolated the roasting chamber is from the rest of the machine; I think that it's connected to other metal parts in the frame.
Thanks this makes sense, i dont need to bother them with engineering questions I probably wouldnt understand answers...
I thought about it some more and considered it might have advantages in stabilisation of a small system and consistency.

OldmatefromOZ

#95: Post by OldmatefromOZ »

Lwowiak wrote:Thank you for posting this. I have a 1.5kg gas drum roaster and this is quite relevant to my situation.Slightly different BT readings, but close enough and most likely due to type of probe and placement. I roast at 50% for filter and will give this a go as I have made gas adjustments earlier than what you posted.
No worries, it was based around Proaster 1.5kg (reallly 1.2kg and true 1kg roaster) 500 - 600g charge, 8 - 9 min total time.

In essence its pretty simple, stabilised heavy drum, very well insulated. Fill it so that it can recover quickly and that mass is easily tossed in a gentle even stream of hot air, preserving the prized aspects of good quality green.

Which brings us full circle in that this type of roast is not a great way to showcase low quality green or old poorly stored.

Lwowiak

#96: Post by Lwowiak »

luca wrote:There are tonnes of problems with buying green in Australia.

Our market is small, so we just don't have a very competitive green coffee market for home roasters. There are a few dominant suppliers and then a few that have stuff as a sideline.
.
Hey Luca, your first statement is spot on. However the green coffee market for home roasters is extremely competitive, with many home roasters being very price sensitive. They are not easy to please. It is also highly skewed to espresso, rather than filter. Naturals with bin juice ferment seem flavour of the month and even win roasting competitions. Others try to pass off commercial grade "blenders" as exotic micro lots.

As you know, finding really good quality greens requires lots of research and cupping. Even then, the roasted samples are not a good reflection of the bean and some importers send out atrociously roasted product that cannot be evaluated.

Anyway thanks for starting this thread and keep posting. Quite a few of us find it very informative.

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ducats

#97: Post by ducats »

luca wrote:Allrighty, I'll have a go ...

I'm less sure on this than on the easier stuff like the visual defects, and I may not have described it well, but you guys are all thinking exactly the same as I am. It's probably either baggy/old green or baked, and I'm leaning more towards old green. For two main reasons: (a) it's more papery than toasty, which sort of shows the limitations in discussing these things in words rather than us tasting the same thing and (b) it doesn't really seem to have any fruit at all; it's a very light roast level and very fast, so if I had baked it, I'd expect to still get at least some fruit; this is very flat. But I've got more of this stuff, so I'll give a shot to manipulating the curve to have the ROR decline more precipitously; I mean, what else am I going to do with it?



Wow, leave some question marks for the rest of us!

1. Auto marked by Roest and set to auto mark on the first crack it detects.
2. I've only done 1200 roasts, so I haven't settled on anything. I think that was probably a 100g roast, but at the moment I'm at 120.
3. Don't know what you mean by "more rounded".
4. The crack lines are their way of showing the number of cracks. So the shortest line is one crack, the next tallest is two cracks, etc. So with the taller line, the machine is telling you it heard two cracks in the same second. The lines really aren't that useful; I guess they do give you an indication of progression of the roast. For example, I have one natural coffee that cracks ludicrously early and has erratic and slow cracks over a long time; ethiopian coffees tend to give a million cracks in rapid succession, centrals give relatively few cracks, etc. The crack count that they have added is probably more useful than the bars, and it does seem to hold true that if you have significantly more cracks, the coffee tastes more developed/roasted.
5. Yes, paddle and fan speeds both fixed in this profile. They can be changed. Fan speed can be changed physically on the machine, but only in increments of 5%. RPM can only be edited from web portal, not on the machine itself.
6. Yeah, I think those settings worked for some coffees. But I'm using power profiles and leaving the end to be finished off manually, since different coffees crack at different times, etc. You can extract air temp profiles from logs, but not power profiles, unfortunately. And I don't like air temp profiles. Different coffees can require markedly different roasting parameters on roest, I think, at least. I've got a profile that I'm trying for washed ethiopian coffees with increasing RPM.
7. Yes, normal charge temp. Ish. I mean, you can roast from cold or from 250c and produce a palatable roast under either condition.
8. I think I've tried about two or three other roasts; can't quite remember what profiles, but all similar results in the cup. You're right to ask this - I think a general rule is just go fast and light and see if that gets rid of the problem; if it's still there, it's probably a green issue.
9. No, not watery. Why do you ask? What would watery tell you?

Looking at this graph, it looks like I overrode the profile with manual control early, being a little scared that it wouldn't get there. Probably needed maybe a bit more heat earlier and some more aggressive drops later. I guess?

OK, over to the next person if they want to play ...
Yes, lots of questions. A severe handicap to diagnose a roast I haven't cupped on a machine I haven't used, but such is the internet.

3) I expected BT at turning point to be more v-shaped whereas it was more u-shaped. The more U it is the bigger the batch size...maybe, not sure. Curve smoothing could also influence as could probe thickness. I would suspect short roast like these would like a more v-shaped turning point. If it looks normal to you, maybe it's not an issue.
4) Alright. Looks like I would have called crack around 4:45, ~20 seconds later than ROEST, but there is that RoR dip right after where ROEST called it so maybe ROEST nailed it. But if at 4:45 then that's only 30 seconds or so in Dev. That's why I was wondering how low your percent loss was.
9) I think I've heard slight underdevelopment described as watery.
OldmatefromOZ wrote: Pushing too much green with too much heat for the given environment over a short period of time.
I think I'm with Stephen if I read his statement correctly. Some sort of mild under-development from either 1)batch size too big or 2) not roasting long enough. Regardless, under-development would be the first thing I'd want to rule out. So if it was me I'd do the same roast, same beans, same everything, but go 10 seconds longer in Dev, but maybe you've already done this. Then again if the real culprit is that they're old greens, "fixing" the profile might not make an improvement in the cupping.

So you have any data for color analysis or moisture content? That would probably help. Don't expect you to. How long have you had these greens? Do they look like a uniform screen size?
luca wrote: But I've got more of this stuff, so I'll give a shot to manipulating the curve to have the ROR decline more precipitously; I mean, what else am I going to do with it?
That could be the sequel to this thread.

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mkane
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#98: Post by mkane »

Luca, come and visit the US. We have a spare room and a TO roaster we built you can use. Royal & Sweet Marias are just down the road.

GDM528

#99: Post by GDM528 »

How about this scenario:

Coffee cherries laid out on an open-air drying bed. Many beds have an overhead screen, but not all. Very photogenic, with the blue sky and fluffy clouds in the background - and trees... Trees = birds, and I've personally participated in birds jettisoning excess 'ballast' shortly after launching from a tree.

A bird 'seasons' a small patch of cherries on the drying bed. Some of the cherries may have breaks in their skin that would allow external 'stuff' to infuse into the bean. It goes unnoticed, and those special greens continue their journey through processing that all but erases any external clues of just how special they are.

Every bean is unique, and stays unique until I roast it, grind it, and brew it into my cup. It's my dubious excuse for the occasional shot that tastes, well, like...

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mkane
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#100: Post by mkane »

Most of if not all the coffee farms we've been to have no cover on the drying beds.