Why does Koshu taste like that?

Characteristically very low tannin, medium-plus acidity and light-medium body. Commonly associated with grapefruit, yuzu, white peach, green tea.

Not claiming: That every wine from this variety shows these characteristics. This is the range across the category, and site and winemaking move wines within and beyond it.

A wide day–night temperature range is associated with better acid retention, because cool nights slow the respiration that consumes malic acid while warm days continue to ripen the fruit.

Not claiming: That altitude or continentality guarantees high acidity. Both widen diurnal range on average and neither determines the outcome.

Autolysis of spent yeast releases mannoproteins and other compounds that contribute texture and weight, and savoury bready characters.

Varies: Effect scales with time and is increased by stirring the lees.

Not claiming: That a bready or brioche character proves long lees ageing. Other routes to similar descriptors exist.

Fermenting in a vessel that contributes nothing, to preserve fruit and freshness.

Not claiming: That every producer of this style uses this method, or that using it is required.

Made to be drunk within a year or two. The delicacy that defines it is the first thing to fade, and lees-aged versions extend that only somewhat.

Not claiming: That a wine of this style will develop these characters. Ageing potential varies by producer, vintage and storage, and most wine is better young.