Bottle variation

One factor is found in the variable oxygen transmission rate (OTR) of cork stoppers, which translates to a degree of bottle variation.

[1] Before the advent of inexpensive stainless steel tanks, it was not customary to blend all the wine together and bottle it at once, a process called assemblage.

Exposure to heat or light can cause a wine to mature more quickly or even make it taste "cooked".

Bottles aged in the chilly cellars of Sweden's alcohol monopoly are famous for tasting younger than the same wine stored at a more typical 13 °C (55 °F).

Bottles stored together their entire lives, with no obvious faults, can taste completely different.

Two bottles of the same Chablis Grand Cru wine showing considerable variation in colour at 30 years of age. The darker colour of the right-hand bottle indicates considerably more oxidation in this bottle. Since the fill level of this bottle is also slightly lower, a slightly faulty cork seal is likely the cause.