Why Do Chardonnay Taste Buttery and Creamy?
The grape does not grow tasting like popcorn. A specific cellar process, entirely separate from oak, is responsible.
Chardonnay doesn't grow on the vine tasting like popcorn. That entire buttery, creamy character that's either loved or actively avoided by name is added afterwards, by a specific process that has nothing to do with the grape itself and everything to do with a choice the winemaker made in the cellar.
The mechanism: malolactic fermentation
Malolactic fermentation (MLF for short) converts sharp malic acid — the same tart acid found in green apples — into softer, rounder lactic acid, the acid found in milk. It's driven by bacteria, not yeast, and winemakers can choose to encourage it, block it, or let it happen on part of a blend and not the rest. A byproduct of that conversion, a compound called diacetyl, is directly responsible for the buttery, creamy character — it's the same compound, incidentally, that gives movie-theatre popcorn its artificial butter flavour. The "buttery" note isn't a metaphor. It's the same molecule.
Oak is doing a separate job entirely
Vanilla, toast, and a rounder, creamier texture from barrel ageing are a completely different mechanism — compounds extracted from the wood itself, plus the texture effects of slow oxygen exposure through the barrel's pores. A Chardonnay can go through full malolactic fermentation with no oak at all and still taste buttery; equally, an oaked Chardonnay that's had MLF blocked will taste toasty and vanilla-ish without the creamy, buttery layer on top. They're independent choices that happen to get made together often enough that people conflate the two.
The grape that proves it
Chablis is made from the exact same grape — Chardonnay — as a rich, buttery Californian bottling, and tastes almost nothing like it: lean, flinty, high in acid, with barely any of that creamy character, because the region's own rules and its winemaking tradition favour little to no oak and often little to no malolactic fermentation either. Same grape, same species, completely different set of decisions in the cellar — which is the whole point. "Buttery" was never a fact about Chardonnay. It's a fact about what was done to it after picking.