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Permalink Reply by Jacob Casella on October 18, 2012 at 9:33am

Unfortunately I don't know any specific resources to turn you towards, but I think it's generally accepted that soil does affect taste--it's probably the only big variable left in terroir after you subtract processing, genotype, etc.  I've heard that the relatively fresh volcanic soils of the Indonesian islands account for some of their rich earthiness, and that good Kenyan's awesome acidity is partially due to the mineral content of those soils.  Wish I had some concrete resources, I'm curious also.

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Permalink Reply by Daniel Williamson on October 19, 2012 at 11:08am

Get a hold of a good green importer.  I'm sure they have a ton of resources and can answer your questions.

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Permalink Reply by Brady on October 21, 2012 at 5:34am

This question has a couple of sides, some with clearer answers than others.

Soil as a growth medium has a huge effect on the cup quality. Variations in drainage, pH, and levels of several nutrients have an impact on plant health and fruit formation and therefore effect cup quality.

There's a short section in this article that discusses the ways terroir may affect our cup, from George Howell Coffee. They also discuss other aspects of the farm location.

In Espresso Coffee, the fine folks at Illy also did a pretty good paragraph, which I'll pull some quotes from:

"Among the essential elements, nitrogen, potassium, calcium, zinc, and boron are considered the most important."

"The endogenous level of potassium will influence the total sugar and citric acid content and is a key element during bean filling.

"Nitrogen is important for amino acid and protein buildup and influences caffeine content. N-fertilization increases total nitrogen in beans, with a weak negative correlation to cup quality"

"Calcium is an essential element for cell wall formation providing more compact beans and improving the resistance to pathogen attacks."

"Boron influences flowering and fruit set, consequently affecting yield."

On the question of contributions of specific minerals to cup flavors or aromas, I don't think there's much science-based info on this out there. At least I can find very little in my (limited) library and web searches.

Here's a lengthier (yet still pretty unsubstantial) conversation on the subject from coffeed back in '06.

Does the specific mineral content of the soil influence the flavor of the coffee? Probably. However, since it is just one of many location-related variables that impact the result in your cup, it would be challenging for one to determine exactly how.

Keep digging (hah) and post back what you find in your search?

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Permalink Reply by Peter P. Simonsen on October 23, 2012 at 4:09am

Thank you, yes I will keep digging (:)) and if I find something I will most definetly share it. Thanks for the information, it is very helpful.

Brady said:

This question has a couple of sides, some with clearer answers than others.

Soil as a growth medium has a huge effect on the cup quality. Variations in drainage, pH, and levels of several nutrients have an impact on plant health and fruit formation and therefore effect cup quality.

There's a short section in this article that discusses the ways terroir may affect our cup, from George Howell Coffee. They also discuss other aspects of the farm location.

In Espresso Coffee, the fine folks at Illy also did a pretty good paragraph, which I'll pull some quotes from:

"Among the essential elements, nitrogen, potassium, calcium, zinc, and boron are considered the most important."

"The endogenous level of potassium will influence the total sugar and citric acid content and is a key element during bean filling.

"Nitrogen is important for amino acid and protein buildup and influences caffeine content. N-fertilization increases total nitrogen in beans, with a weak negative correlation to cup quality"

"Calcium is an essential element for cell wall formation providing more compact beans and improving the resistance to pathogen attacks."

"Boron influences flowering and fruit set, consequently affecting yield."

On the question of contributions of specific minerals to cup flavors or aromas, I don't think there's much science-based info on this out there. At least I can find very little in my (limited) library and web searches.

Here's a lengthier (yet still pretty unsubstantial) conversation on the subject from coffeed back in '06.

Does the specific mineral content of the soil influence the flavor of the coffee? Probably. However, since it is just one of many location-related variables that impact the result in your cup, it would be challenging for one to determine exactly how.

Keep digging (hah) and post back what you find in your search?

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