How many draught lines can your pub afford? The weekly pints each tap needs to pay its way

Every draught line costs you beer every week whether it sells or not. On a 10-metre run, what sits in the line at cleaning time plus the pull-through afterwards is about 3 pints a line, every clean. A line selling 300 pints a week barely notices. A line selling 30 loses roughly a tenth of everything it pours. As a working rule, a keg line under about 60 pints a week, or a cask line that can't clear its container inside three days, is costing more than it earns and belongs on a review list.

Range sells pubs. I'm not arguing for a bar with two lagers and a bitter. I'm arguing that every tap should be there because you chose it, with the numbers in front of you, rather than because it was there when you took the place on. Autumn is the time to do it, before winter trade drops and the slow lines get slower.

The fixed cost of a line

Two things go down the drain on cleaning day, and neither cares how much the line sells. First, the beer sitting in the python. As I worked out in the line cleaning guide, standard 3/8 inch bore holds about a pint and a quarter per 10 metres of run. Second, the pull-through to clear cleaner and water before you serve again. Cellar guidance puts that at 2 to 3 pints a line, and I'm using the low end.

So on a 10-metre run it's about 3.25 pints a line, every week if you clean weekly. On a 5-metre run over the cellar it's nearer 2.6. On a 20-metre run to a remote bar it's 4.5. That's the floor before anything else goes wrong.

It ties up with the national figure nicely. Beer Piper's research, reported by the Morning Advertiser in 2019, put line cleaning waste at about 20 pints a week for the average pub. Six lines at 3.25 pints is 19.5. Same number from two directions.

What that waste is as a share of each line

Here's where it gets interesting, because the same 3.25 pints is a rounding error on one tap and a disaster on the next.

Line sells a week	Cleaning waste as a share of what the line uses
400 pints	0.8%
200 pints	1.6%
100 pints	3.1%
75 pints	4.2%
50 pints	6.1%
30 pints	9.8%

My arithmetic: 3.25 pints a clean on a 10-metre run, weekly cleaning. In money, 3.25 pints a week is 169 pints a year, which is about £264 at a £1.56 cost price, and about £900 of beer you could have sold at the £5.34 average pint. Per line. The busy line and the slow line cost the same to clean. Only one of them can carry it.

Vianet, whose kit was on nearly 250,000 connected devices at the time, came at this from the quality side in their 2019/20 insight report: every under-used tap on a bar costs around £500 a year through quality and wastage, and over-tapping was costing the industry £71.4m a year on their assumption of three excess taps a pub. Older figures, and from a company that sells monitoring, so treat them as a direction rather than gospel. The direction matches the arithmetic.

Cask has a clock as well

Keg lines lose to cleaning. Cask lines lose to cleaning and to time. Cask Marque's guidance is to empty a cask within three days of putting it on sale, and the maths that follows is the reason so many third handpulls are quietly losing money. My cask breather guide has the full days-to-empty table. The short version:

Container	Nominal pints	Working sellable pints	Pints a day to clear it in 3 days
Firkin	72	About 65	About 22
Pin	36	About 30	About 10

The sellable figures are my working estimates after sediment and line fill. If a cask line can't do 22 a day while it's on, it either needs pins instead of firkins or it needs to come off. A breather buys a few days, but if every cask needs one to survive, the problem is the line count, not the air.

Keg is gentler on time but not immune. Brewers set their own on-sale windows for a connected keg and they vary by product, so ask your brewer's quality team for theirs rather than relying on a figure off the internet. On a slow keg line, dropping from a 50-litre keg (88 pints) to a 30-litre (about 53) shortens how long each one sits on the line, if your supplier does the smaller size.

What it does to your stocktake

Every line is another row on the variance report. The busy lines are steady. The slow lines are where the noise lives, because a fixed 3 pints of cleaning waste against 30 pints of sales shows up as a 10% loss on that row unless it's logged. Add a cask that went over on day four and that one handpull can be the worst line on your report while having nothing at all to do with how your team pours.

If you keep a slow line, log the cleaning waste against it every clean, as a wastage entry against the product, so the variance already has it explained. Then judge the line on what's left. The acceptable variance guide covers what "left" should look like.

The review, line by line

Pull the last eight weeks of pints by line from the till and divide by eight. Not your gut, the till. Then for each line:

Keg under about 60 pints a week goes on the list. That's the point where cleaning waste passes 5% of what the line uses on a 10-metre run. Longer runs push the threshold higher. Cask that can't clear its container in three days goes on the list too.

For each one on the list you've got honest options. Drop it. Swap it to a smaller container. Make it a rotating guest that shares a line with something else, so one python carries two products across the month. Or keep it on purpose, because it's the beer a group of regulars come in for, and price it to carry the waste.

That last one deserves a number. Recovering 3.25 pints of waste at £1.56 across a line selling 30 pints a week is about 17p a pint at cost. To hold a 65% GP on that, you'd need around 58p a pint more on the bar, inc VAT. Nobody's charging 58p extra for the slow ale. Which tells you the slow line is subsidised by the busy ones, and that's fine if you've decided it's worth it. What isn't fine is not knowing.

Before you pull anything, check your agreement and who owns the kit. In a tie, the range and the dispense equipment can be part of the deal, and the conversation with your BDM goes better with these numbers in hand than with "it doesn't sell". The tied versus free-of-tie guide covers the stock side of that relationship.

What I'd do this week

Count your taps. Pull eight weeks of pints by line. Measure one line's run with a tape, or catch what comes out at the next clean before the water hits, so you know your real pints per clean instead of my 3.25. Then put any line under the threshold in front of you with its waste in pounds next to it, and make the decision on purpose. If you do take a line off for winter, the par levels guide will help you reset what you order for the lines that stay.

Common questions

How many draught lines should a pub have?

As many as each one can justify on sales. As a rule of thumb, a keg line needs roughly 60 pints a week on a 10-metre run before cleaning waste drops under 5% of its volume, and a cask line needs to clear its container within three days. Count your lines against eight weeks of till data rather than a target number.

How much beer does each line waste when it's cleaned?

The beer in the line plus the pull-through. Standard 3/8 inch line holds about a pint and a quarter per 10 metres, and pull-through to clear cleaner is 2 to 3 pints, so roughly 3 to 4 pints a line every clean on a typical run.

Is it worth keeping a slow-selling line?

Sometimes, if it's a beer people come in for. Price it knowing it carries a fixed cleaning loss every week, log that waste against it so it doesn't look like a pouring problem, and consider a smaller container or sharing the line with a guest.

How quickly does a cask need to sell?

Cask Marque guidance is to empty a cask within three days of putting it on sale. That's about 22 pints a day from a firkin, or about 10 a day from a pin, using working sellable figures after sediment and line fill.