Lady of the Glen – Whisky Education Series Episode 2: Cask Sizes: Why Size Matters in Whisky (But Not How You Think)
Welcome back to Lady of the Glen’s Whisky Education Series. In Episode 1, we explored how different oaks influence whisky flavour. Today, we’re zooming out — or in — to talk about cask sizes, and why they matter in single cask whisky.
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Why Cask Size Matters
In our latest outrun, we used a variety of cask sizes: butts, hogsheads, barrels, and some exclusive octaves. Each size affects flavour differently.
A quick reminder from our last episode — a cask influences whisky in four ways:
1. Adds colour from the oak.
2. Removes undesirable compounds (like sulphur).
3. Extracts oak flavours (vanillin).
4. Allows reactions between the spirit, the oak, and oxygen over time.
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The Rule of Thumb
Smaller cask = more spirit-to-wood contact. More contact means faster extraction of colour and wood flavour.
But here’s the catch: smaller casks don’t actually mature whisky faster. Those long-term chemical reactions and oxidation still take years. In fact, strong wood flavours in a small cask can mask — rather than remove — certain undesirable compounds. The result? Bold but sometimes less balanced flavour.
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| Cask Type | Approx. Capacity | Origin / History | Typical Use in Scotch |
| Butt | 500 L | Sherry industry | Sherry maturation / finishing |
| Port Pipe | 465 L | Port industry | Port maturation / finishing |
| Puncheon | 450 L | Sherry casks, later coopered in UK | Long maturation |
| Hogshead (HHD) | 254 L | Recoopered from American barrels | Most common Scotch cask |
| Wine Cask | ~220 L | Wine industry | Wine finishes |
| American Barrel | 200 L | Bourbon industry | Single malts & blends |
| Octave | 40–60 L | Small custom casks | Intense short finishes |
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Custom Constructions
At Lady of the Glen, we sometimes commission unique builds — like HHDs with first-fill barrel ends — to see what flavour twists we can create. Because casks are handmade, capacity can vary slightly, even between casks of the same type.
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Final Thoughts
Cask size shapes whisky flavour, but it’s just one piece of the puzzle. Time, oak type, and spirit style are just as important. The magic happens when all three work in harmony.
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Whisky Glossary
First Fill – The first time a cask is used to mature Scotch whisky after being seasoned (e.g., with sherry or bourbon).
Finish – Moving whisky into a different cask for the final stage of maturation to add extra flavours.
Hogshead (HHD) – A common Scotch cask, often rebuilt from bourbon barrels to hold ~250 litres.
Octave – A small cask of 40–60 litres used for rapid flavour addition.
Recoopered – A cask rebuilt or altered in size by a cooper.
Seasoning – The process of preparing a cask (often with sherry, wine, or other liquids) before whisky maturation.