Published: Jan 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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  1. presidentgaud1

    You mean, a shallow roast means the beans are underdeveloped?

    • BHLearn

      Hi presidentgaud1, yes, if you notice a gradation of colour where the surface of the beans in a roast batch is noticeably darker than their centres, this indicates the beans are underdeveloped. BH

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