Ask ten people in the trade what draught wastage is normal and you'll get ten numbers, most of them either a guess or a sales pitch. One American vendor site tells you the average bar loses 15 to 25% of its draught beer, which is the kind of number that sells monitoring kit. Build the figure from the actual places beer goes without being sold and a well-run UK pub loses 4 to 6% of its draught volume before anything has gone wrong. Past 8%, something specific is broken and it's findable. Here's the arithmetic.

Where draught beer physically goes

The keg. An 11-gallon keg holds 88 pints. You will not sell 88. There's fob at changeover, the drip tray, the beer standing in the line when the keg blows, the pint that comes off cloudy while the new keg settles. A realistic sellable figure is about 84 to 86 pints from an 88-pint keg, which is a built-in loss of 2 to 4.5% before anything's gone wrong. Calibrate your kegs and your stocktake will tell you your own number per product.

The cask. A firkin holds 72 pints and cask is where wastage gets personal. You lose sediment at the bottom, you lose what you pull through tasting it into condition, and if a cask doesn't drop bright you can lose a lot more. Between all that, mid-60s sellable from a 72-pint firkin is a fair planning number. Cask loss varies so much between cellars and beers that the only honest advice is to measure yours cask by cask, which is exactly what a dipstick or weight reading at each stocktake gives you.

The lines. Cleaning a line pulls the beer standing in it straight down the drain. A 10-metre run of 3/8-inch python holds about 1.25 pints, and in practice each line costs 2 to 3 pints per clean once you've pulled through to clean water and back to beer. Six lines cleaned weekly is roughly 15 pints a week, and on this the industry numbers are grim reading: Beer Piper's estimate, reported by the Morning Advertiser in 2019, put line cleaning waste at 40 million pints a year across the UK. I've costed all of this out in the line cleaning guide.

So what's the honest percentage?

Run the arithmetic for a tidy wet-led pub doing 800 draught pints a week on six lines. Keg and cask built-in losses at the container level, call it 3% blended if you're mostly keg, worse the more cask you sell. Line cleaning at 15 pints is another 1.9%. Before a single mistake, a well-run pub is losing 4 to 6% of its draught volume, and a cask-heavy pub can be honest and still sit a point or two above that. My own arithmetic, but every input above is checkable.

That's volume, not value, and it's why I never accept a bare percentage without asking what's in it.

The UK-wide data says most pubs sit worse than the arithmetic says they should. Vianet's Beer Insight report (2019/20, still the most recent published, built from 11,000 sites pouring 570 million pints a year) found 61% of pubs weren't hitting their target pouring yield, about 2% of drinks poured never made it through the till, and 27% of beer was served through lines overdue a clean. Old data now, but nobody has published anything on that scale since, and the physics of a beer line hasn't changed.

One more UK rule worth knowing: BBPA and Cask Marque guidance says a pint served with a head must be at least 95% liquid and a top-up should never be refused. Generous heads and refused top-ups both quietly move your yield, in opposite directions.

What isn't wastage

Half the "wastage" I see blamed on the cellar is nothing of the sort. A part keg estimated by eye instead of weighed or dipped is measuring error. Pints rung on the wrong button are till mapping. A "one in the pump" pint paid for before the count is timing. I've written up how to tell pouring waste from measuring error and why the till doesn't match the stocktake, because if you log real waste as it happens and count properly, your variance stops being a mystery number and starts being a short list.

And a warning on the money: line cleaning waste carries its duty down the drain with it, about 50p a pint on a 4.5% beer at 2026 rates, and it is never claimable. Genuine ullage in returned containers is a different story with its own rules, which I've covered in the ullage claims guide.

The allowance trap

Plenty of stocktakers apply a standing draught allowance before they call a result a surplus or deficit. Fine as far as it goes, but know what allowance your stocktaker uses, because a blanket allowance can hide a real problem exactly as easily as it can excuse an honest one. A pub that records actual waste (every line clean, every fobbed pint, every cask that wouldn't clear) doesn't need anyone's allowance. Its number is its number, and what counts as acceptable variance gets a lot easier to answer.

Common questions

Is 5% draught beer wastage normal?

For a pub that cleans its lines weekly and sells some cask, around 4 to 6% of draught volume is defensible arithmetic rather than carelessness. If you're mostly keg on short lines, you should be under that. Past 8% something specific is wrong and it's findable.

How many pints do you actually get from an 11-gallon keg?

It holds 88. Realistically, 84 to 86 sellable once fob, the drip tray and line ends have taken their share. Calibrate your kegs properly and your stocktake will tell you your own number per product.

How many pints does cleaning a beer line waste?

Around 2 to 3 pints per line per clean on a typical run, more on long pythons. It's the price of selling beer that tastes right, but it belongs in your waste log, not in your variance.

Does draught wastage show up in my GP%?

Directly. Every unsold pint raises your real cost per pint sold. It's one of the first places to look when GP% drifts, and a weekly count with waste logged tells you whether the drift is wastage or something else.

Sources

  • Vianet Beer Insight report 2019/20 — 11,000 sites, 570 million pints a year: the pouring yield, till and line cleanliness figures.
  • Beer Piper via the Morning Advertiser, 2019 — 40 million pints a year lost to line cleaning across the UK. Costed in our line cleaning guide.
  • Milton Brewery firkin guide — the 72-pint firkin.
  • BBPA and Cask Marque guidance — a pint served with a head must be at least 95% liquid, and a top-up should never be refused.
  • Author's arithmetic — sellable pints per container, pints per line clean, and the 4 to 6% blended figure. Duty per pint from HMRC's February 2026 rates, worked through in our duty guide.