Allt-a-Bhainne 20 Years Old 2000 Cask Strength Sister (Signatory CSC)

Distilled in 2000 and bottled by Signatory Vintage in 2021 under the Cask Strength Collection imprint, this is a 20 Years Old Allt-a-Bhainne at 52.4% ABV from Oloroso sherry maturation. The release is one of 703 bottles, a sister cask to the 52.6% Signatory release from the same vintage and bottling year, with nearly identical strength and bottle count suggesting twin cask filling.

Allt-a-Bhainne ferments malted barley for 48 to 50 hours on Mauri liquid yeast in closed stainless steel washbacks, then double distills through two copper wash stills and two copper spirit stills with steam heating and shell and tube condensers. The short Speyside ferment produces a clean malt forward spirit built as a blend filler for Chivas Regal, Passport and 100 Pipers. New make is reduced with Rowantree Burn water and tankered to Keith for cask filling and maturation, since the distillery holds no warehousing on site.

Oloroso sherry maturation drives the spirit through rancio chemistry, where slow polyphenol and aldehyde oxidation during prior sherry contact generates the dried fruit, leathery and nutty register typical of long sherry contact. Against the lighter Allt-a-Bhainne distillate the sherry contribution leads. The dual sister cask release pattern lets buyers compare cask to cask variation within an identical vintage and bottling year, a common Signatory approach for the Cask Strength Collection.