A cask's "fill number" tells you how many times it's been used to mature spirit — and it dramatically affects the result.
What the terms mean
- First fill — first time used for your type of spirit (often after holding bourbon, sherry, wine). Most active, strongest wood influence.
- Refill (second, third fill…) — used before. Gentler, slower flavour contribution.
Why it matters
- First-fill casks impart colour and flavour faster and more intensely
- Refill casks give subtler maturation and longer working life
- Knowing fill number lets you predict a cask's contribution
Track it per cask
Recording fill number on each cask profile lets you choose the right cask for the result you want — see choosing the right cask. It also informs when a cask is spent and should be retired.
See it on your own production: Book a demo.