Terroir is a collective term for all the particulars of a locality (climate, soils, topography) that shape the quality and flavor of ag products such as wine grapes and coffee beans. Terroir is the reason why so much time is spent discussing why certain regions of the globe are critical for the highest quality production of prized varietals such as Cabernet Sauvignon and Pinot Noir.
It's long been my impression that fruits tend to produce better flavors when the plants have been beat up a bit. A lot of the chemicals that we perceive as flavor and scent are involved in plant defense from pathogens, pests and harsh weather. Drought in particular has long been known to be critical for the production of quality wine grapes since it concentrates sugars and other chemicals in the berries.
I came across a paper on this topic the other day. The authors followed gene expression and levels of antioxidant, pigmentation, flavor and scent chemicals over time in Cab and Chardonnay grapes that either were, or were not, exposed to drought conditions. Not surprisingly, they found that drought increased the amount of these chemicals in wine grapes. Their results also suggested that much of this was mediated by the plant hormone abscisic acid (ABA).
I'm not sure what I think of this kind of reductive food science. It's fascinating to be able to understand our basic experiences in such detail, but I'm not sure what practical benefit it offers. Most of these types of studies seem to just lead to nutritionists latching on to a few chemicals out of thousands in something as complex as a grape, declaring them 'healthy,' and leading people to take vitamins and supplements that supposedly recreate the best parts of a varied diet with large doses of a few chemicals.
On the other hand, perhaps a more full understanding of how plants regulate the production of these important suites of chemicals will lead to the breeding and engineering of plant varieties (or plant hormone sprays) that are more obliging in the production of high-quality, flavorful fruit under a broader range of conditions.