Stainless steel and refrigeration change what is possible

Before reliable refrigeration, fermenting white wine in a warm climate was close to impossible to do well. Fermentation is strongly exothermic, and an uncontrolled ferment in a hot cellar loses aromatics and oxidises.

Jacketed stainless steel tanks solved both problems at once: an inert, airtight, cleanable vessel whose temperature could be held wherever the winemaker wanted it.

The consequences were geographic. Australia, Chile, South Africa, southern Spain, southern Italy and much of California could suddenly make fresh, aromatic white wine, and entire categories of wine that now seem ordinary did not previously exist.

It also enabled the modern tank method for sparkling wine, and it made reductive winemaking — protecting aromatic compounds from oxygen — a controllable technique rather than a hope.

It is arguably the most consequential technology in twentieth-century wine, and it is invisible to the drinker in a way that oak and closures are not.