A bottle of rare 60-year-old Macallan could fetch a record price at a Bonhams Edinburgh auction on Wednesday as buyers show an unslakable thirst for limited-edition scotch whiskies.

One of just 12 bottles released in 1986, it carries a pre-auction estimate of 900,000 pounds ($1.17 million), which exceeds the current record of $1.1 million set by a bottle of the same 1926 vintage in May at Bonhams Hong Kong. The limited edition’s label was designed by Italian artist Valerio Adami.

Prices for whiskies have soared globally in recent years as more buyers seek rare bottles from Scotland including Dalmore and Port Ellen, as well as Japanese distilleries Karuizawa and Yamazaki. Whisky has appreciated 140 percent in the past five years, according to the Vintage 50 Index compiled by Rare Whisky 101, outpacing the 19 percent advance of the Liv-ex 100 Benchmark Fine Wine Index.

While a wine’s vintage is determined by the year in which the grapes were picked — bottling usually takes place within 16 to 24 months after the harvest — the age of a whisky refers to the time spent aging in a cask. For example, the Macallan 60 year old from 1926 wasn’t bottled until 1986. Because of continued loss due to evaporation, known as the “angel’s share,” older whiskies produce fewer bottles, adding to their rarity.