The Gist
Old World Pinot Noir tastes tense and earthy — forest floor, iron, mushroom, high acid. New World Pinot tastes plumper and fruitier with more visible oak. The more earth you smell, the more likely it's Burgundy; the more ripe red fruit you smell, the more likely it's California or New Zealand.
Mechanism
Burgundy Pinot Noir is produced in one of the most marginal climates for red wine production. This produces wines with high acid, lower alcohol, more earthy complexity (mushroom, forest floor, iron), and less obvious fruit. New World Pinot (Willamette, Central Otago, Sonoma Coast, Martinborough) has warmer growing conditions, riper fruit, more oak influence, lower acid, and less tertiary earthiness.
In the glass: Burgundy Pinot feels tense, earthy, iron-mineral, high-acid, restrained fruit. New World Pinot feels open, fruit-forward, riper, more oak-evident, rounder. The earth/fruit balance is the key: more earth = Old World. More fruit = New World.
Deeper mechanism
Central Otago Pinot Noir is the most structured of the New World expressions — high altitude produces cold nights that retain acid and build phenolic structure. It can approach Burgundy in tension but lacks the forest-floor earthiness. Willamette Valley is the most Burgundy-adjacent American expression.
Confusion analysis
Côte de Nuits vs. Willamette Valley Pinot
Both: pale ruby, silky tannin, high acid. Burgundy: forest floor + iron + mushroom + dried rose. Willamette: red cherry + cola + gentle earth (no forest floor intensity). The earthiness gradient is the separator.
Related varietals
This concept comes up when tasting: Pinot Noir