While it’s true that coffee is world’s most consumed beverage, not all coffee-lovers will have the same preference when it comes to their favorite coffee roast. Some people prefer a light roast, others talk about dark Italian roasts while most choose from the plethora of roasts in between the two extreme ranges.
Why is it important to know about the relation between color of beans and the corresponding coffee roast? For those who roast their own coffee beans or plan to do so in the very near future, the color of beans is the primary cornerstone to judge the degree of roasting. Coffee bean colors can tell the roasters a lot about the resulting flavor and aroma when the brewed coffee is finally poured into a cup.
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Color of Beans Determines the Degree of Roasting
The extent to which the coffee beans have been roasted plays an important role in determining the characteristics of the resulting coffee, i.e. taste and fragrance. Although most individuals don’t realize this, coffee beans are not really beans, but seeds. The foremost coffee drinkers and traders called these beans owing to their bean-shaped appearance, and the colloquial term stayed on.
The natural, unroasted coffee seeds are green, and this forms the baseline for the coffee bean color chart. Coffee beans are generally stored in their green state. The green beans on their own do not exhibit any of the properties of roasted beans – they are soft and easy to bite. In fact, a novice may not associate the green color of beans with coffee at all.
Once the green coffee seeds are picked, processed and packaged, the roasting process transforms them into the distinct aroma-filled, flavor-packed, crisp beans we all know as coffee. The flavor and aroma of the coffee is brought through the chemical changes that take place inside as well as on the outside of the coffee bean. Once the desired level of roasting is achieved, the roast coffee beans are rapidly cooled to lock down the perfection in terms of flavor and aroma.
However, the fact remains that each degree of roasting confers distinct and unique flavor notes and aroma to the pertaining cup of coffee when brewed. Also, it can’t be denied that the preferences of coffee-lovers across the world vary vastly. Hence it is important for coffee enthusiasts to understand the degree of roasting, done through close observation and monitoring the color of beans during the roasting process.
Coffee Bean Color Chart – Know Your Roasts
Coffee roasts from lighter or darker color of beans. While there are several roasting stages, the general rule remains the same – the darker the bean color, the longer its roasting duration. The naturally occurring sugars in the bean tend to caramelize during the roasting process, gradually turning from sweet to burnt-like towards the end stages.
Since different coffee beans achieve different roast levels at different temperatures, depending on the origin characteristics of the beans, roasting machine and method used, the color of the beans is the easiest yardstick to understand the degree of roast.
Here is the commonly employed coffee bean color chart that determines the extent of roasting, and the pertaining properties of the roast beans:
| Color of Beans | Image | Roasting temperature (°F) | Properties |
| #1 Green Coffee Beans – Unroasted |  | 75 | – Natural, sealed-in aroma & flavor – Spongy texture, grass-like flavor |
| #2 Beginning to Pale |  | 270 | – Takes 2-5 minutes depending on the make and type of roasting machine used |
| #3 Early Yellow Stage |  | 327-330 | – Bean starts to lose moisture but no physical expansion happens – Humid, hay-like fragrance materializes |
| #4 Yellow Tan Stage |  | 345 | – Steam begins to emerge from beans – Toasty smell, similar to toasted bread or grain. – Early appearances of browner shades. – Marbling patterns begin to emerge on the bean surface. |
| #5 Light Brown Stage |  | 370 | – We proceed towards the paramount 1st crack – The central crack in the center of the coffee bean opens up slightly, signifying minor expansion – The chaff or silver skin on the exterior of the coffee bean begins to shed |
| #6 Brown Stage |  | 390-395 | – Preliminary stage to 1st crack – Considerable browning occurs due to caramelizing or reduction of sugars, as well as from Maillard reaction (burning of amino acids) |
| #7 1st Crack Stage |  | 401 | – First crack occurs, which sounds distinctly like a bowl of Rice Krispies or popcorn pops – As internal bean temperature reaches about 356°F, carbon dioxide is released from within, and the beans physically expand. |
| #8 Mid-1st Crack Stage |  | 415 | – Internal temperature of bean rises to 370°F, wherein melting point of sucrose is achieved. Caramelization begins inside the bean – Bean expansion continues even as the brown color looks mottled and uneven. – The center groove almost loses its chaffed texture – Essential to keep the heat supply ongoing so that the further caramelization process can be carried forward |
| #9 1st Crack Finishes |  | 425 | – Bean surface looks smoother drom the expansion, is harder at the edges, and dark etched patterns can be noticed on the bean – This stage is called City Roast, and the beans are now officially considered as coffee – Carbon dioxide release fastens at this point |
| #10 City+ Roast Stage |  | 435 | – Knocking on the door of the 2nd crack, which is 15-30 seconds away – Bean surface is allowed to smoothen, softer at the edges |
| #11 Full City Roast |  | 444 | – On the verge of the 2nd crack – Characterized by softer edges and light oily luster on the surface of the beans – Considerable swelling of beans due to outgassing of carbon dioxide and water – Also known as French roast! |
| #12 Full City+ Roast |  | 446-454 | – Bean barely enters the 2nd crack at 446°F – A few subtle cracks are heard, following which the roasting process should be halted – Few beans continue into the 2nd crack even in the cooling phase which is also known as coasting – Beans resemble shade of dark chocolate – The faster the cooling process, better the ability to achieve the extent of roast one prefers |
| #13 Vienna – Light French Roast |  | 465 | – Also known as Continental stage – Mostly preferred for flavor notes of distinct origin coffee – Roasts begin to be characterized by carbon-like roast flavors. |
| #14 Nearly Carbonized |  | 465-474 | – Rapidly achieved after 2nd crack stage – Very dark brown-black shade of beans due to burnt out or caramelized sugars – Nearly carbonized, wood-like bean structure – These beans result in a coffee that is very light, since most of the aromatic oils and compounds have been burnt out during roasting – Smoking starts at this stage of roasting. |
| #15 Fully Carbonized |  | 485 | – Characterized by beans turning into nearly-charcoal stage – Fills the roastery / home with smoke – Fully carbonized beans |
| #16 Imminent Fire Stage |  | 496 | – Full on carbonized, ashy, loose beans which are literally on the verge of fire – The beans need to be dumped quickly onto a cool tray to prevent a potential large fire – Dark black beans, similar texture to charcoal. |
As is evident from this color chart, as the coffee beans get darker, the sugars caramelize and the oils start to loosen down, making the resulting cup lighter and filled with roasted aroma. Thus it is important for roasters to take the color of the beans as a tentative reference for achieving the desired aroma and flavor.
Color of Beans – Few Tips for Achieving the Perfect Roast
Consistency is the Key!
This goes without saying – roasting is a science, and no roastery could ever have achieved that perfect roast on the first go. The key to achieving the perfect color of beans that one loves to brew is consistency, so it helps to remain patient and learn about the coffee bean colors and corresponding roasting stages via several rounds of trial and error.
Investing in a Good Roasting Machine Helps
While drum roasters can help in turning over larger quantities of roast beans, air roasters allow for more efficient heat transfer and hence facilitate quicker roasting. Talking to professional roasters and reading about different kinds of roasting machines available out there would help one make educated decisions about their machine preference. Some machines even have an inbuilt chroma-meter to check the color of roast bean in an accurate manner, thus avoiding the angle of human error.
Use Your Eyes and Good Sense
The best way to judge whether a particular roast has reached perfection or not, is to use your own eyes! Even with the umpteen technological advancements made in the world of coffee roasting, there is no accurate yardstick that can be applied to bring uniformity in color of beans once they’re roasted.
Roasting levels are subjective – no two City Roasts developed in different parts of the world could ever be absolutely same. The confusion will stay on, and hence it helps to use your own eyes and good sense as the measure of a roast’s perfection.
Conclusion – Roasting and Color of Beans
We now know that since coffee beans from different origins vary in size, shape and characteristics, coffee roasters employ the color of beans as a helpful guide to determine when to stop roasting. This guide helps coffee enthusiasts and roasters achieve the perfect degree of roast, by estimating the color of beans through the various stages of roasting.