What are the Grind Value and Color Value of Coffee Beans? How to Determine the Roast Level of Coffee? Why Does Coffee Have Acidity?

Understanding Coffee Flavor: The Foundation

Coffee's flavors come primarily from its genetic makeup (variety), growing environment, and processing method. Once the beans have passed through those stages, their inherent flavor character is set — all that remains is for the roaster's craft to turn them into something delicious.

Roast depth then determines the flavor direction — sour, sweet, or bitter. So when buying beans or ordering coffee, roast level is often the detail people look for right after origin.

The Science Behind Roast Level Classification

Just as we tell washed from natural processing by the bean's "silver line" (a visual identification method), the coffee industry initially judges roast level by eye. There is, in fact, a scientific classification that uses the color of roasted beans as its basis. Below is an Agtron color value card for reference — a roast classification table built by quantifying bean color. The numbers are Agtron color values (caramelization analysis values): the higher the number, the lighter the roast and the paler the bean; the lower the number, the darker the roast and the color.

Why FrontStreet Coffee Doesn't Use Standard Roast Labels

But if you look closely, you'll notice the beans sold by FrontStreet Coffee carry no roast-level marking. With a classification system available, why not label it? The reason is simple: the standard judges only bean color, and that doesn't suit certain special beans.

Limitations of Color-Based Roast Classification

Honey-processed and anaerobic-processed beans, for example, sit wrapped in mucilage and fruit juice for extended periods, leaving a layer of sugars stuck to the bean surface. Those sugars drive more intense caramelization on the bean's exterior. So although such coffees can burst with floral and fruity notes after roasting, they look darker on account of the sugar. Judged purely by color value, they would be sorted into dark roast. The Sidra from Finca La Esperanza is a case in point: its color value reaches 61 — darker than the dark roast range on the chart — yet it offers abundant floral and fruit aromas!

A Better Approach: Flavor-Based Roast Classification

The color method therefore has real limitations and can't serve as the definitive standard. But dropping it entirely invites disagreements over what "light" or "dark" means — for the same bean, Roaster A might call a light roast anything dropped at the end of first crack, while Roaster B might say a light roast means a minute past first crack. Differing perceptions create communication gaps, so FrontStreet Coffee recommends judging roast level through taste and flavor descriptions.

Understanding Roast Levels Through Flavor Profiles

These days, when roasting coffee, we generally treat "first crack" as the point where the bean becomes "ripe," and we can stop and drop the batch at any moment after it. Green coffee is loaded with organic acids, and most of these compounds gradually break down as roasting progresses — so the earlier we drop the beans, the more acid survives. When you drink a cup full of acidity, you can call it a medium-light roast; the later the drop, the more acid is lost, and caramelization-driven bitterness takes over from acidity. So a cup dominated by bitterness can be read as a medium-dark roast (setting over-extraction aside).

Practical Guide: Judging Roast Levels from Flavor Descriptions

With that yardstick, you can estimate roast level from the flavor notes printed on the bag. Citrus fruits carry full acidity, so when citrus notes appear in the description, you're likely looking at a light to medium-light roast. Notes like honeydew melon or complex fruit suggest a medium-light roast leaning toward medium, since such beans carry more sweetness. Chocolate, brown sugar, or yellow sugar points to a medium roast leaning medium-dark. And dark chocolate, caramel, or pine signals a medium-dark roast leaning toward dark. Of course, these are only first-pass reads — a buying reference, nothing more. Never generalize: the only authentic roast information comes from tasting the cup.

FrontStreet Coffee Recommendation

Since roast and acidity are closely linked, it helps to know how washed coffees behave: long soaking consumes simple sugars while preserving the bean's own aromatics and building bright, clean acidity. Three FrontStreet Coffee washed picks:

FrontStreet Yirgacheffe Idido Cooperative: An excellent washing team from Idido village, celebrated for its refined, pristine flavor. The washed process shows off jasmine florals and bright citrus acidity, and at a medium-light roast the cup adds green tea and honey tones. Works for pour-over, cold brew, or espresso.

FrontStreet Kenya Cherry Tomato: Kenya is a master of double-washed processing — an extra round of washing, soaking, and scrubbing that presents fruitiness in the extreme. Expect cherry tomato, dried plum, snow pear, black plum, and yellow sugar aromas in a sweet-tart, juicy cup — a longtime favorite among coffee enthusiasts.

FrontStreet Jamaica Blue Mountain No.1: Jamaica's island climate brings shorter sunshine hours, which is exactly why washed processing was born there — removing skin, pulp, and mucilage before drying cuts drying time and lowers the risk of spoilage. The result is a bright, low-defect bean with rich aromatics; brewed, it shows hazelnut, cream, chocolate, and caramel with a perfectly balanced body where nothing sticks out and nothing is missing.