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January 30, 2017 /
Roast Development and Colour

A while back I posted Let’s talk about roasting. This was in reference to three sliding scales of roasting: colour, development, and last-minute behaviour. I’d like to take this information on a different spin, comparing just development and colour.

Roasts come in many colours, and I’m not going to dictate what’s best. Instead, think of “light” as too light for you, “medium” as your ideal, and “dark” as too dark for you. It doesn’t matter if you like light roasts, just think of “medium” as your ideal roast colour, and the other two are objectionably light and objectionably dark.

If your roast doesn’t taste green/stemmy/grassy/savoury then it’s developed. This means all of the bean is roasted to a medium or darker colour.

If your roast does have green/stemmy/grassy/savoury flavours then it’s underdeveloped. This means part of the coffee bean is too light and you can taste it. Note: the whole bean doesn’t have to be too light for it to be called underdeveloped.

There’s also no such thing as overdeveloped coffee. If this word comes to mind then you probably just mean “too dark”. Development isn’t a scale like colour, it’s a yes/no thing. Here’s a simple flow chart:

Is there any part of the bean that’s too light?
|        |_  Yes (it’s underdeveloped)
|_ No (it’s developed)

The important thing here is to know that a coffee may have different levels of development throughout. The inside of the bean is always lagging behind the outside when roasting because the heat energy takes a while to penetrate. This means it’s very easy to have a developed exterior, but an underdeveloped (too light) interior.This could also be termed an “uneven development”. If any portion of the inner bean is displaying underdeveloped flavours, then the entire coffee is underdeveloped.

High resolution image here.

Here are some things to note in this graphic:

  • The Dark + Light coffee is underdeveloped, even though the exterior is dark.
  • The Medium + Light coffee is underdeveloped, even though there’s only a little bit in the middle that’s too light.
  • The Dark + Medium coffee is developed. There’s no such thing as overdevelopment.
  • Medium means your ideal roast colour. Not mine, or anyone else’s. (although if your ideal roast colour is super light and grassy, I can’t help you).

Please feel free to share and use that image. All I ask for is a mention!

If you disagree with anything above, I’d love to hear it down below in the comments! 🙂

 

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Alexey Fedorovskiy
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Alexey Fedorovskiy

Nice! i’ll use that more than 1 year, and it really work. Absolutely agree with this post, but it’s really bad when some roast masters dont know that things, and still work with specialty coffee.

Arnhem Coffee Roastery
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Arnhem Coffee Roastery

Agreed, when I started home roasting I learnt this lesson from another professional roaster – his simple test was to bite through a few beans to check the level of development through the profile of the bean. I have continued to do it ever since.

Evan Schubarth
Guest
Evan Schubarth

Agreed. There is lots of negative things to say about each roast color, but developed or not is more correct. We stopped saying light or medium or dark, and started saying brown. What kind of brown are we at in the chemistry. Undeveloped acids and sugars brown, developed acids and caramelized sugars brown, or carbony brown. What’s your flavor?

Andrew Stock
Guest
Andrew Stock

This isn’t a disagreement per se. Actually, disagree isn’t the right word. I guess it’s more of comment on language, in that I feel an annoyance with the constant redefinition of the terms ‘light, med, dark.’ By redefining these terms in this article, they work for your explanation. It’s not hard to observe that consumers (and industry folk) are all over the map in understanding what these gradient references actually refer to. I appreciate the discussion of developed and underdeveloped. I think it’s constructive. Redefining already confused terms though – it just makes things more confusing. Geez that was long… Read more »

Boston Aristocracy
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Boston Aristocracy

Thank you for taking the time to write this article. Very helpful

Dmitry Boroday
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Dmitry Boroday

But your scheme is not right:) you can produce many results with dark part inside and light part outside(is about airflow)

MJ Valour Lewis
Guest
MJ Valour Lewis

I do see what you mean, depending on what colour medium is to each person. For me medium is a few shades lighter than the medium displayed above. I’m no roast expert, but a smart man by the name if Matt Perger showed me in a blog that evenness is key in coffee. For roasting I see no difference, no matter what shade of medium is, so long as there are no grassy green vegetable flavour notes present… Any thoughts?

mo
Guest
mo

I totally see what you’re getting at Matt but I can’t help but think that there is a point in roast development where my “subjective ideal medium” would be pushed passed ideal in terms carmelization of sugars and breakdown of acids. What I’m wondering is, why do I have to call this too dark (for me). Why can’t I call this overdevelopment? ‘Under’ as a prefix in ‘underdevelopment’ is a value statement relative to a desirable, or ideal, point in development. Conceivably, one could develope a coffee to a point of diminished acidity, but with little or no signs of… Read more »

luke po
Guest
luke po

Dark inside with light outside? but how does the heat get in!

four lore
Guest
four lore

Yea man – tbh I think that the statement of ‘overdeveloped’ is just semantics, in the end. since there are many different points of yes or no development in a given roast/bean. – yes, we may over ride and say a coffee is underdeveloped – or on a another roast its only developed. however, in a really dark roast next to a balanced medium roast – there are still many levels of ‘darkness’ or ‘too dark’ the semantics part is… it sounds much nicer to say this is overdeveloped.. than to say its ‘too dark.’ I guess what you are… Read more »

sapphire courchaine
Guest
sapphire courchaine

I really would love to hear Matt Perger, why you feel there is no such thing as over developed coffee. From a chemistry or scientific stand point. I’m struggling to wrap my head around your statement. There is a prior thought in this industry, at least at a local level, that if it is “dark” it is indeed over developed. Please explain this. I’m not entirely disputing what your saying, but your not providing enough factual evidence as to why there is no such thing as over developed coffee. I could see, that yes in the right parameters and right… Read more »

Matt Perger
Guest
Matt Perger

It’s real simple.

Everything you talk about is indeed a very dark roast. That’s a colour.

We *need* development to be decoupled from colour because it’s confusing. Development is y/n formation of delicious flavours.

sapphire courchaine
Guest
sapphire courchaine

Yes I understand that we need development to be decoupled from color, however, color does give us some clues about roast development and how it went. I can sort of agree that development is y/n in some ways, however that is subjective to the individual tasting the coffee. I do believe there is still a correlation between development of roast, and whether or not it is over/underdeveloped. I’m sure there must be someone out there that can have an even roast, indicated by even color throughout, like in your chart above, and still might be able to have flavors that… Read more »

Matt Perger
Guest
Matt Perger

See me comment above. You need to separate development from colour/degree/depth.

Matt Perger
Guest
Matt Perger

I think you should read it again.

The medium above is *your* ideal medium.

Matt Perger
Guest
Matt Perger

If that happens then you have bigger problems than colour and development!

tionico
Guest
tionico

Coming late to this party due to internet service problems keeping me offline. I believe something that may help understand Matt Perger’s thinking here is to ask/answer the question “development of WHAT? As the Mailard reactions begin and continue, the thing that is being “developped” is sugars. They are being formed up from the various components of the bean itself as the heat effects chemical and physical changes within the bean. Thus, before those sugars are “developed”, and is, formed, they are NOT “developed”. This, as noted, results in the sour, grassy, etc “off” flavours that comprise one aspect of… Read more »

Erhard Dinges
Guest
Erhard Dinges

For me this is playing with words. When a dark coffee is bitter or and ashy and has other unpleaseant qualities
it is overdeveloped for my. And there is much between. A

sapphire courchaine
Guest
sapphire courchaine

I am sorry, definitely not trying to be confusing. Correct me if I’m wrong, but you do at the beginning of your post mention that if you taste “grassy” notes for example that “part of the bean is too light” and thus underdeveloped? I do 100% agree with those statements. I just find it might be difficult to say to some that “there is no such thing as over developed coffee” when most of our community still defines development of a roast based on color. I however do not, numbers and data are our friends I believe. I think alot… Read more »

Matt Perger
Guest
Matt Perger

What you’re saying isn’t wrong.

How you’re saying it is extremely confusing.

You’re mixing development with colour/degree.

Please read the post again 🙂

Diego Marroquin
Guest
Diego Marroquin

I´ve seen that before, but I do not think that´s a problem with the airflow: using a handmade in México roaster and a probatone 5 (the first without airflow) I can get a medium color outside, and dark inside.

What kind of big problems could them be?

Jorge Caro
Guest
Jorge Caro

Hi Diego,

Have you seen/got any under developed issues roasting coffee due airflow applied or what’s your experience due your Mexican HandMade roaster limitations?

I use a Hand Made Roaster also, obviously it’s a basic oaster with a few control limitations, i’ve roasted really good coffees before, but lately I’ve been experiencing lot of under developed issues.

tionico
Guest
tionico

microwave?

Imile de Villiers
Guest
Imile de Villiers

But what if the inside is still green? Is it then overdeveloped and underdeveloped? This is confusing and having different words to describe such a situation might be better.

The tide is pulling back on 3rd Wave – @jonathonsciola
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The tide is pulling back on 3rd Wave – @jonathonsciola

[…] are roasting darker (more soluble) moving back towards a traditional Italian profile and away from single origins only […]

Dmitry Boroday
Guest
Dmitry Boroday

So, can we have a blind experement? I roast 10 smaples the same beans and different roast profile(also about color inside outside) you will cup it blind. After you evaluate colors and give feedback. And we will see the results:) i know that you can have darker inside, but taste will better:) also i’ll send you green beans and you will check your “ideal”.

Caleb Holstein
Guest
Caleb Holstein

Sorry for the late input I only just saw this post. I find this conversation a little one dimensional about the development occuring when roasting coffee. If we can all appreciate the fact that the development of a roast is vastly more intricate than just the change in visible colour and a yes/no development scale. Then we can begin to use scientific equipment providing scientific evidence to progress and develop our understanding of roast development and the effect it can have on the final product.

Imile de Villiers
Guest
Imile de Villiers

No, what I was trying to say is that describing it as overdeveloped creates confusion, because if your beans are green inside and black outside you will have to say it is both underdeveloped and overdeveloped. Rather describe it as dark and underdeveloped.

Erhard Dinges
Guest
Erhard Dinges

That’s it! Green inside under-, burnt outside overdeveloped. Very simple.

Matt Perger
Guest
Matt Perger

No, read it all again. ***any*** underdevelopment or “too light” areas = underdeveloped. Regardless of outside.

Jon Tekak
Guest
Jon Tekak

Thank you. ive been telling people this for years. finally someone who shares the same thinking

속까지 고르게 익어야 로스팅 잘 된 원두다! | 위키커피 (WIKI COFFEE)
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속까지 고르게 익어야 로스팅 잘 된 원두다! | 위키커피 (WIKI COFFEE)

[…] 기사 인용 출처: https://baristahustle.com/roast-development-colour/ […]

Cody Fergusson
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Cody Fergusson

I’m joining this discussion extremely late…. But I had to say something. First, brilliantly put, Matt. I completely agree. For those arguing the existence of “overdevelopment”: once a coffee is roasted through to the center and is fully “cooked”, development is done. If any part of the coffee is still green after being dumped from the roaster, it is underdeveloped. Once the coffee has been roasted through and through and you continue to roast it for longer, it only gets darker in color, burnt in taste, and of course lighter in weight. Development here only refers to roasting a coffee… Read more »

Devinfahada
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Devinfahada

Does it any specific differences between light in the outside develop in the inside than full develop (in and out), and what’s the effect on the flavor?

Eduardo Siegismund Walther
Guest
Eduardo Siegismund Walther

Im getting in my roast nice medium color outside but dark inside. I roast in a HG5 2009 I have tried so many differents ways but all my profiles end up dark inside if someone could explain me this I can go back to sleep at night 🙂

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