How much does beer line wastage actually cost your pub?

Last updated: 26 June 2026

A 1% stock loss on wet sales quietly costs a typical pub £3,000–£5,000 a year — and most licensees don’t even know where it’s going. You think you’re losing it to theft or pouring error. The truth is uglier: beer line wastage is eating your margin every single day, and your brewery stocktaker isn’t going to catch it because they’re not measuring what actually went down the drain.

If you’re running a pub on a spreadsheet and a prayer, you’re probably experiencing this right now. You know your till sales don’t match your stock counts. You know something’s wrong. But without a proper weekly line check — dipping casks, weighing spirits, checking cellar temperature and checking what actually came out of the tap — you’re just guessing at the damage.

I ran my own pub on spreadsheets for years before I built a proper stock routine. Within two weeks of moving to a disciplined weekly count using a dipstick and scales, my variance went from total chaos to a number I could trust. More importantly, I stopped haemorrhaging money on line waste I couldn’t see.

This article tells you exactly what beer line wastage costs, where it’s coming from, and the one simple system that catches it before it hits your bottom line.

What is beer line wastage?

Beer line wastage is not one thing — it’s everything that comes out of your taps but never reaches a customer’s glass and never gets rung into your till.

The most effective way to understand beer line wastage is to track three separate sources: draught line purging, cask sediment loss, and line cleaning spillage. These three things alone account for the majority of unseen beer loss in any pub cellar.

Draught line purging happens when you change a keg. You’ve got gas pressure in the lines, dead beer sitting in the pipes, and sediment that needs flushing. Even a careful barperson is pouring three to five pints down the drain before the beer runs clear. Multiply that across four draught lines and ten keg changes a week, and you’re looking at fifty pints of pure waste before you’ve even opened properly.

Cask sediment loss is different. A firkin of real ale sits in your cellar for two weeks. The last two or three pints in any cask are lees — sediment, water, dead yeast. You can’t sell it. You have to empty it. Most pubs don’t measure this waste at all.

Line cleaning spillage is the one most people forget about. You’re meant to clean your lines every two weeks (many pubs skip this, which costs them more). When you do it properly, you’re running cleaning fluid through the entire system. That fluid, plus the beer it pushes ahead of it, ends up in a tray. Nobody measures what actually came out.

Add poor cellar temperature (beer warms up, goes flat, has to be discarded), forgotten kegs left standing too long, and the odd tap left running overnight, and you’ve got a silent profit drain that looks like theft but isn’t.

How much beer line wastage actually costs

The numbers are brutal once you start measuring properly.

A 1% stock loss on wet sales quietly costs a typical pub £3,000–£5,000 a year. That’s not an edge case. That’s what most licensees experience without realising it.

Let’s do the maths. A typical free house or tenanted pub does £8,000–£12,000 in wet sales per week. Let’s say £10,000. Over a year, that’s £520,000 in wet revenue. A 1% loss is £5,200 straight off the bottom line.

But here’s the thing: that’s not your profit loss. That’s your cost of goods sold (COGS) loss. If your draught margin is 65%, you’re actually losing profit at a higher rate. A £5,200 COGS loss represents a £3,380 profit loss (at 65% margin). Some pubs see it even worse than that.

And that’s assuming you’re only losing 1%. Most pubs running on spreadsheets and guesswork are losing 1.5–2% before they tighten up.

Here’s what that looks like on your bottom line:

• 1% loss: £3,000–£5,000 profit leak per year
• 1.5% loss: £4,500–£7,500 per year
• 2% loss: £6,000–£10,000 per year

For a tenanted pub paying a tied rent, that’s the difference between hitting your target and falling short. For a free house, it’s the difference between a decent living and a stressful one.

Where the money actually goes

Most of the time, pub licensees blame theft. An honest barperson is keeping the money. A dishonest one is stealing it. But that narrative misses what’s actually happening in your cellar.

Most stock ‘theft’ is actually measurement error and forgotten wastage because spirits hide losses in over-pouring, draught hides it in poor cellar temperature and bad line cleaning waste, and stock variance is often just what nobody measured in the first place.

Let me break down where your money is actually going:

Draught beer losses (40–50% of total wastage)

This is the biggest silent drain. A keg sits in your cellar on gas. When it runs empty, you disconnect it and put a fresh one on. The lines are full of old beer. You open a tap and let it run until it clears. That’s typically three to five pints per keg change. If you change kegs ten times a week across four lines, you’re throwing away 30–50 pints of beer just to clear the lines. At £2.50 per pint profit, that’s £75–£125 per week from line clearing alone.

Add poor cellar temperature — if your fridge is sitting at 8°C instead of 4°C, the beer degasses faster and goes flat — and you’re discarding another 10–20 pints a week just from spoilage.

Spirit over-pouring (20–30% of total wastage)

This one is rarely deliberate theft. It’s just how people pour. A 25ml measure is supposed to hold 25ml. In reality, a free-poured 25ml often comes out at 32–35ml. You’re giving away an extra 7–10ml on every single spirit drink. Over a busy week, that’s two or three full bottles of vodka or gin that walked out the door for free.

The only way to catch this is to weigh open bottles. Put a spirit bottle on a kitchen scale at the start of your shift. Weigh it again at the end. If you’ve poured forty 25ml measures, the bottle should be down by exactly 1 kilogram. If it’s down by 1.25kg, you know you’re over-pouring by 6ml per measure. That’s 240ml per night — real money.

Cask sediment and spoilage (15–20% of total wastage)

Real ale sits in a cask. The bottom 15–20% of the cask is lees — sediment and water. You can’t sell it, and most pubs don’t measure what they throw away. A firkin of ale costs you roughly £40 in COGS. If you’re writing off the last two pints of every cask, that’s £5–£7 of waste per cask. With twenty casks a month, that’s £100–£140 just in unmeasured cask waste.

Line cleaning and forgotten waste (10–15% of total wastage)

Line cleaning happens (or should happen) every two weeks. When you run cleaning fluid through your lines, you’re also pushing out three to five pints of beer ahead of it. Most pubs don’t measure this. Nobody knows how much actually came out. Same with kegs left standing too long before being tapped, or a tap left running overnight because someone forgot to close it properly.

How to measure and catch wastage weekly

You cannot manage what you do not measure. And you cannot measure something that happens in your cellar if you’re not going down there every single week with a dipstick, scales, and a till printout.

The number that actually matters is wet GP by line, not a single headline stock figure, because spirits hide losses in over-pouring, draught hides it in poor cellar temperature and bad line cleaning waste, and most stock ‘theft’ is actually measurement error and forgotten wastage.

Here’s what a proper weekly line check looks like:

Step 1: Dip every cask and partial keg

A dipstick costs £3. You put it in the cask, it tells you the level. Write it down against the cask number. The next week, you dip again and work out how much came out. Do this for every draught line and every real ale cask in stock. Takes fifteen minutes. Tells you exactly what volume left your cellar.

Step 2: Weigh every open spirit bottle

A kitchen scale costs £10. Every spirit bottle that’s open gets weighed at the start of your shift (or at a fixed time each week) and again at the end. If a bottle went from 1.2kg to 0.8kg, you know 400ml came out. You can then check the till to see how many 25ml measures were sold. If thirty measures sold but 400ml came out, you’re over-pouring by 8ml per measure. That’s actionable data.

Step 3: Record what you threw away

At the end of every shift, your bar staff should note what got discarded: flat pints, spilled beer, line clearing, spoiled cask, anything. Even a rough note — “three pints from line clear, two from spoiled ale” — gives you a weekly total. Measure it in a jug if you need to. Most pubs think this is too much work. It’s not. It’s two minutes.

Step 4: Match it to till data same day

Pull your till report. Work out total pints and spirits sold. Add the waste you recorded. That should equal the total volume that left your cellar according to your dips and weighs. If it doesn’t, the difference is your variance. Do this every single week. After four weeks, you’ll see a pattern. After eight weeks, you’ll know where the leak is.

When I moved from a spreadsheet mess to this system, the variance went from ±15% (which I was calling “normal”) to ±2% within two weeks. Suddenly I could see that my draught margins were 3% better on Mondays (when I’d cleaned the lines) and 2% worse by Friday (as lees built up). I could see that my vodka measures were creeping up in summer (warm hands pouring bigger). I could see exactly which barperson’s shifts had tighter variance. Real data. Not a guess.

The weekly line check system that works

The system doesn’t require fancy software. It doesn’t even require a spreadsheet if you don’t want one. But it does require discipline, the right equipment, and a place to record the data that you’ll actually look at every week.

At my pub, I built a simple routine around a dipstick, a set of kitchen scales, and a notebook. Every Friday afternoon at 2pm, before service, I dip every cask, weigh every open spirit, note the temperature in the fridge, and jot down what’s been thrown away that week. Takes twenty minutes. I then grab the till report and reconcile it within an hour. I know my stock position and my variance before Friday service even starts.

Most pubs that move from a messy spreadsheet to a disciplined count claw back 1–2 GP points within a couple of months. That’s not because they’re suddenly losing less — it’s because they’re measuring it and stopping the bleed.

If you want to formalise this, the StockTap pub stock app is built by a working pub landlord specifically for this job. It logs your dips, weighs, temperatures, and waste in one place, matches it to till data automatically, and shows you your variance by line and by shift. You’re not guessing. You’re not juggling spreadsheets. You’re just recording what you see, and the app does the maths.

The key thing is consistency. You do this every single week. Same day, same time, same routine. After three months, you’ll know more about your stock position and your margin leaks than most licensees learn in a year.

Common objections answered

“I don’t have time for a weekly stocktake.”

A proper weekly line check is not a stocktake. A stocktake is counting every bottle, every glass, every measure. That takes hours. A line check is dipping your draught lines, weighing your open spirits, and noting what you threw away. Fifteen to twenty minutes, tops. If you can’t find twenty minutes a week to see where £5,000 a year is leaking, you’re not serious about running a profitable pub.

“My spreadsheet works fine.”

Does it? Or does it tell you a headline stock figure that doesn’t match your till and you’ve stopped asking questions about? Most pub spreadsheets don’t match dip data to till data in real time. They’re just a ledger of what you bought and what you sold at list price. They’re not catching variance, and they’re definitely not catching where the variance is coming from. A spreadsheet can work, but only if you’re actually using it to reconcile dips, weighs, and waste every single week. Most licensees aren’t.

“Do I really need special equipment?”

You need three things: a dipstick (£3), kitchen scales (£10), and a notebook or an app (free or £97). That’s it. Total outlay is under £15 if you’ve already got a pen. You don’t need expensive cellar monitoring systems or software subscriptions. You need to go down there and measure what’s actually there.

“Won’t the brewery stocktaker just do it for me?”

The brewery stocktaker comes once a month or once a quarter. They count what’s on the shelf. They don’t dip your casks properly, they don’t weigh your spirits, and they’re not measuring daily waste. They’re trying to reconcile against their invoices, not your till. By the time they spot a variance, you’ve already lost six weeks of margin. You need weekly line checks, not quarterly reconciliation.

“Is an app safer than a spreadsheet for my records?”

An app on your phone or tablet is more secure than a spreadsheet shared on Google Drive or left on a USB stick. But the real answer is: the app is only as good as the data you put in. If you’re disciplined enough to dip, weigh, and record wastage every week, an app just makes the reconciliation automatic. If you’re not disciplined, neither will save you. The SmartPubTools system keeps your data on secure servers and backs it up automatically. But honestly, the bigger question is whether you’re actually doing the work weekly. The tool is secondary to the habit.