Cask sizes and what they yield

Every cask size in common use

Ordered by capacity. Where published sources disagree, the range is given rather than a single figure — the disagreement is real and worth seeing.

The bottle count is the number to check

Every valuation of a cask is a bottle count multiplied by a bottle price. Both halves move, and the bottle count moves for a reason that is easy to state and rarely stated.

Spirit goes into the cask at about 63.5% ABV. It loses roughly2% of its contents a year to evaporation — more in the first year or two, often 3.5 to 4% — and the strength falls with it, reaching around 58% after twelve years. So a 200-litre barrel holds something like 180 litres by then.

Bottled at cask strength, those 180 litres make about 257 bottles of 70cl. Diluted to 40% ABV — perfectly normal, and legal down to that floor — the same whisky makes about 373 bottles. That is 45% more bottles out of one cask, without a drop of extra whisky.

Which is why the two figures have to come from the same assumption. A sales projection that takes the diluted bottle count and multiplies it by the price a cask-strength bottling commands is not a forecast; it is two incompatible scenarios multiplied together. Every yield in the table above states its basis for that reason.

The figures here assume a full cask. A cask that has already lost volume — which any regauge certificate will show — starts lower, and evaporation is not recoverable.

What may legally have been in the cask before

The Scotch Whisky Technical File was amended to set this out explicitly, superseding the guidance the industry had operated under since 2010. Scotch must mature in new oak, or in oak that has held only wine (still or fortified),beer or ale, or spirits — with three exclusions:

• wine, beer, ale or spirits produced from, or made with, stone fruits;
• beer or ale with fruit, flavouring or sweetening added after fermentation;
• spirits with fruit, flavouring or sweetening added after distillation.

The practical consequences are sharper than they look. An ex-cherry or ex-plum brandy cask is out, because those are stone fruits. A spiced rum cask is out, because the spice went in after distillation — while a plain rum cask is fine. An ex-tequila cask is fine. And whatever the cask, the result must still have the traditional colour, taste and aroma of Scotch, which is a judgement the distiller carries rather than a box to tick.

Casks must also be empty of their previous contents before filling. That rule has history: until the Scotch Whisky Order was revised in 1990, tired sherry casks were routinely rejuvenated with paxarette, a dark, sweet fortified wine concentrate, sometimes injected under compressed air. It was reclassified as a flavouring additive and banned.

Sherry casks are seasoned, not second-hand

A sherry butt is the most desirable cask in the table and the most misdescribed. The image sold is a cask that spent decades holding sherry in a Jerez bodega before being retired into whisky. That trade barely exists at the scale the industry needs.

What actually happens is that distillers commission bodegas to build casks to their specification and season them with sherry-style wine for roughly 12 to 24 months — Macallan and GlenDronach are known to pay for longer. The wine that comes out is heavily tannic and generally goes for vinegar or distillation rather than sale. The cask is bought for what the oak has taken up, and the wine is a means to that end.

None of this makes the whisky worse, and it is not a scandal. It matters because "ex-sherry" is priced as though it denoted age and provenance, when for most casks it denotes a procurement process about eighteen months long.

Notes on individual casks

Octave · 45–50 L

Octaves are the size most often sold to first-time private buyers, because the headline price is low. The trade-off is rarely stated: the same geometry that matures the whisky quickly also evaporates it quickly, and the per-bottle share of any fixed fee — storage, regauge, bottling — is far higher than on a hogshead.

The fastest-acting cask in common use. An eighth of a butt by name, with a surface-area-to-volume ratio several times higher, so colour and tannin arrive within months rather than years — and over-oaking is easy.

64 bottles — Filled to capacity, roughly a tenth of the volume lost to evaporation over about ten years, bottled at cask strength into 70cl bottles. Small casks lose proportionally more, so treat this as an upper bound.

American standard barrel (ASB) · 190–200 L

Bourbon may only be matured in charred new oak under 27 CFR 5.143, so every bourbon barrel is legally single-use. That regulation is the reason Scotland has a cheap, abundant cask supply at all — over 90% of Scotch matures in ex-bourbon wood.

The industry workhorse. Charred American oak gives vanilla, coconut and soft caramel, with a faster extraction than a hogshead because the surface-area-to-volume ratio is higher.

260 bottles — Published trade figure of 260–270 bottles, consistent with a full cask losing roughly a tenth of its volume to evaporation over about a decade and being bottled at cask strength into 70cl bottles.

Barrique · 225–300 L

Sources disagree on the size: the classic Bordeaux barrique is 225 litres, but casks sold to the whisky trade as barriques are frequently 300. The name describes a shape and a provenance more reliably than it describes a volume.

Toasted French oak gives spice, clove and a drier tannin than the vanilla-forward American barrel. Used mainly for finishing, where a few months is often enough.

289 bottles — Filled to capacity, roughly a tenth of the volume lost to evaporation over about ten years, bottled at cask strength into 70cl bottles.

Hogshead · 250 L

A hogshead is not a size a cooper starts from. It is built by taking the staves of about five ex-bourbon barrels, adding new ends and rebuilding them as four larger casks — which is why the wood is American oak but the cask is assembled in Scotland.

Slightly slower extraction than a barrel due to lower surface-area-to-volume ratio, giving vanilla and coconut notes with a softer oak influence over long maturations.

321 bottles — Filled to capacity, roughly a tenth of the volume lost to evaporation over about ten years, bottled at cask strength into 70cl bottles.

Butt · 500 L

A modern sherry butt is usually not a cask that held drinking sherry. Distillers commission bodegas in Jerez to build casks and season them with sherry-style wine for around 12 to 24 months; the wine comes out heavily tannic and is sent for vinegar or distillation rather than sale. The cask is bought for the wood, not for a previous life.

Slow, deep maturation. European oak contributes tannin, dried fruit and a darker colour; the low surface-area-to-volume ratio means a butt can carry a whisky for decades without becoming woody.

643 bottles — Filled to capacity, roughly a tenth of the volume lost to evaporation over about ten years, bottled at cask strength into 70cl bottles.

Puncheon · 465–700 L

The least consistently defined cask in the trade. Published capacities run from 465 to 700 litres, a spread of half again, so a puncheon quoted without a litre figure tells you almost nothing about what you are buying.

Similar volume to a butt but a shorter, wider shape, so the wood contact differs slightly. Slow maturation; often used for bulk ageing and blending stock.

643 bottles — Filled to capacity, roughly a tenth of the volume lost to evaporation over about ten years, bottled at cask strength into 70cl bottles. Based on the 500-litre nominal figure — a 700-litre puncheon would yield about 900.

Port pipe · 350–650 L

Port is a fortified wine, so a genuine ex-port cask is permitted for Scotch. Published capacities vary widely — from 350 to 650 litres — because the Portuguese trade uses the word for more than one vessel.

Long and narrow rather than squat. Contributes red-fruit sweetness and a pink-tinged colour, which is why it is favoured for finishing rather than full-term maturation.

771 bottles — Filled to capacity, roughly a tenth of the volume lost to evaporation over about ten years, bottled at cask strength into 70cl bottles. Based on the 600-litre nominal figure.

Madeira drum · 600–650 L

At 650 litres a drum sits close to the 700-litre ceiling that Scotch Whisky Regulations 2009 reg. 3 imposes on maturation vessels. It is among the largest casks a Scotch distiller can legally use.

Wide and short, so despite the large volume the whisky meets a broad head area. Gives a nutty, raisined sweetness; almost always used as a finish rather than for full-term maturation.

836 bottles — Filled to capacity, roughly a tenth of the volume lost to evaporation over about ten years, bottled at cask strength into 70cl bottles.

Questions

What is the maximum cask size for Scotch whisky?

700 litres. Regulation 3 of the Scotch Whisky Regulations 2009 requires that casks used to mature Scotch be made of oak and have a capacity not exceeding 700 litres. A madeira drum at around 650 litres is close to the legal ceiling; anything larger cannot be used to mature Scotch.

How many bottles does a whisky cask make?

It depends on the size of the cask, how long it has been maturing and the strength you bottle at — the last of which changes the answer by nearly half. A 200-litre barrel holding about 180 litres after a decade yields roughly 257 bottles at cask strength, or about 373 if diluted to 40% ABV. Any single bottle count quoted without those assumptions is not checkable.

Which casks can legally be used to mature Scotch?

New oak casks, or oak casks that have previously held wine (still or fortified), beer or ale, or spirits. The Scotch Whisky Technical File excludes anything made from or with stone fruits, beer or ale with fruit, flavouring or sweetening added after fermentation, and spirits with fruit, flavouring or sweetening added after distillation. So an ex-cherry-brandy or spiced-rum cask is not permitted, while an ex-tequila or ex-port cask is.

Are sherry casks actually used to hold sherry?

Usually not, in the modern trade. Distillers commission bodegas in Jerez to build casks and season them with sherry-style wine for roughly 12 to 24 months. That wine emerges heavily tannic and is generally sent for vinegar or distillation rather than sold as drinking sherry. The cask is bought for what the wood has absorbed, not for a previous commercial life.

Why is a hogshead 250 litres when a bourbon barrel is 200?

A hogshead is not built from scratch at that size. Coopers take the staves of roughly five ex-bourbon barrels, add new ends and rebuild them into four larger casks. That is why the oak is American but the cask is assembled in Scotland.