What's Your Agtron Number?

Visitors to the Hula Daddy Kona Coffee plantation ask us if we have dark roast coffee. It is a hard question to answer because “dark roast” is a subjective evaluation. One person’s dark roast is another person’s medium roast.

In most cases, the roast name on the package is the marketing name that the roaster believes will sell the best. We see coffee labeled medium roast that is black and oily – the signature of a very dark roast.

Almost every bag of coffee has a roast description. Many are feel-good marketing names. Some of the common names are Breakfast Coffee, Viennese, Turkish, American, City, French, Italian, Blonde, American Breakfast, Continental, European, Spanish, New Orleans, and Neapolitan.

Some roasters use the name of the variety e.g. Sumatran, Ethiopian, Brazilian. The problem for consumers is that those names don’t help. One roaster’s Breakfast Coffee” may be dark and heavy bodied, while another Roaster may use the same name for a light tea like coffee. Some Ethiopian coffees are amazing and some taste like dishwater.

There are some standard terms for coffee roast levels; light, medium, medium-dark, and dark. However, the terms are also subjective and interpreted differently by each roaster.

The only way to objectively describe the roast level of a coffee bean is to use a color densitometric analyzer. The gold standard for accurate roast levels is Agtron color densitometric analyzer scoring.
The Agtron Gourmet Scale ranges from 0 to 133. A score of 0 is pure carbon, a score of 133 is slightly toasted. Agtron numbers are used to measure the outside of the roasted bean as well as the roasted grounds. The two numbers are then averaged. Sometimes both numbers are reported, so a 55 medium roast coffee might have an outside number of 52 and an inside number of 58 which could be reported as either 55 or 52/58.

Here is a chart showing roast levels with the Agtron scores.

If you like light roasted coffee, you should look for an Agtron score above 60. A medium roast is between 60 and 40. If you want a dark roast coffee, you should pick an Agtron number below 40.

Each year we take samples of Hula Daddy Kona Coffee and roast them to different levels. We then pick the roast that maximizes the body against the acidity but keeps subtle flavors like citrus, chocolate, and cinnamon.

We think there is a sweet spot where both the flavor and body are in balance. But then we roast some of our coffee just a little more because many of our customers insist that they only like dark roasts.

However, we refuse to roast coffee until it is dark and oily. All the flavors of coffee are in the oils. Driving coffee oil to the surface of the bean allows the oil to oxidize and turn rancid.

You don’t often find Agtron numbers on coffee bags. If you are buying from a roaster, you can always ask. We put the Agtron numbers on each of our coffees.

Bon Appetit!


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