Why two bars from different origins taste different

Nearly all of chocolate's aromatic compounds derive from precursors formed during fermentation. Duration, temperature, turning frequency, box or heap, whether the pulp was pre-drained — each changes the microbial succession and therefore the precursor profile.

Regional fermentation conventions are strong. Sambirano ferments differently from Sur del Lago, and much of what reads as national character is a national habit of fermenting a certain way. This is the largest single cause and it is the one origin marketing mentions least.

Roasting converts precursors into aroma and simultaneously destroys some. A light roast preserves fruit and floral notes and exposes any fermentation shortfall; a dark roast builds cocoa depth and buries origin character.

This is why the same beans from the same lot can produce recognisably different bars from two makers. If you want to taste origin, you need a maker who roasts to reveal rather than to standardise.

Variety sets what is possible. Nacional carries the genetic basis for floral aromatics; Amelonado does not. Criollo material has less polyphenol and therefore less astringency at the same fermentation length.

But genetics is a ceiling rather than a result — and since planted varieties correlate with region, a lot of apparent geographic effect is actually genetic effect travelling under a geographic name.

Rainfall, temperature, altitude and soil affect pod development and pulp sugar content, which feeds into fermentation. Local microflora differ by valley and drive spontaneous fermentation. These effects are real and they are the smallest of the four.

Which is the practical conclusion: when a bar tastes distinctive, thank the fermentary first and the soil last.