Keg stock control for pubs

Last updated: 29 June 2026

Most pub licensees have no idea what they’re actually losing on draught beer week to week. You know how much you paid for the keg, you know what you’re selling it for, but somewhere between delivery and the last pint poured, money vanishes. A 1% stock loss on wet sales quietly costs a typical pub £3,000–£5,000 a year — and that’s not theft. It’s measurement error, bad line cleaning waste, temperature drift, and over-pouring that nobody’s tracking. If you’re running keg stock control on guesswork or a spreadsheet you update once a month, you’re already behind. The good news: a proper weekly line check catches it, and most pubs that move from a messy stocktake routine to a disciplined count claw back 1–2 GP points within a couple of months. In this article, I’ll show you exactly how to set up a keg stock control system that works — the same method I built at my own pub after years of losing track of partial kegs and variance I couldn’t explain. This is operator-level detail, not theory.

Why keg stock control matters

Here’s what I learned running stock on a tangle of spreadsheets: you can’t manage what you don’t measure. For years I thought my draught loss was normal. Every monthly stock check showed variance I’d write off as “line waste” or “evaporation.” In reality, I was losing track of partial kegs, not recording when a line had been cleaned and replaced, and over-pouring without a standard measure. The number that actually matters is wet gross profit by line, not a single headline stock figure. Spirits hide losses in over-pouring (a free-poured 25ml is often 32–35ml), draught hides it in poor cellar temperature and bad line cleaning waste, and most stock “theft” is actually measurement error and forgotten wastage.

When I started a simple count routine around a dipstick and a set of scales, the weekly variance went from guesswork to a number I could trust within a fortnight. That number became my early warning system. If variance spiked on a Tuesday, I knew something had changed: a line had blown, temperature had drifted, or someone was free-pouring. I could fix it before the loss compounded.

This matters because keg stock is typically your single biggest inventory line. A typical high-street pub might have £2,000–£5,000 worth of draught stock in the cellar at any given time. If you’re only checking it quarterly, you’re flying blind for 12 weeks at a time. By the time you spot the problem, it’s usually baked into your P&L.

The weekly line check method

The most effective way to control keg stock is to dip every cask and partial keg, weigh open spirit bottles, and reconcile against till data the same day. This is non-negotiable. Here’s the exact routine I follow:

Step 1: Dip every cask and partial keg

Use a calibrated dipstick to measure the depth of liquid in every keg or cask in your cellar. Record the reading to the nearest centimetre. For a standard 50-litre keg, this tells you roughly how many litres remain (most dipsticks have a volume scale printed on them). Do this once a week on the same day — I do it every Monday morning before service.

For partial kegs (anything less than 75% full), also weigh them on a set of digital scales and record both the dip reading and the weight. The scales give you a cross-check: if the weight doesn’t match the dip reading, something’s wrong — either the keg is leaking, the line has been run off, or you’ve got a measurement error.

Step 2: Calculate litres sold

Subtract this week’s dip from last week’s dip. That’s your net usage. Cross-reference it against your till data: how many pints of that line did you sell? A standard UK pint is 568ml. If your till says you sold 50 pints of Guinness but your keg shows only 20 litres gone, you’ve got a problem. It could be over-pouring, a blocked line, or a till error.

Step 3: Calculate cost of goods sold (COGS) and variance

Multiply litres sold by your cost per litre (ask your dray driver or check your invoice). That’s your COGS for the week. Compare it to what your till shows you sold at the pump. The difference is variance. A 2–3% variance is normal (line cleaning, settling, evaporation). Anything above 5% needs investigation.

Step 4: Repeat every week

Do not skip a week. Do not “average it out” over a month. Weekly discipline is what catches the problem early. After a month of weekly checks, you’ll have a clear picture of which lines are losing money, which are tight, and which have structural problems (bad line temperature, blocked lines, or over-pouring staff).

If you’re serious about this, use StockTap pub stock app to log your dip readings and variance calculations automatically. It takes the arithmetic out and gives you a trend line you can actually read. But if you’re not ready for that, a simple spreadsheet with columns for date, line name, dip reading, weight (if partial), till sales, litres calculated, COGS, and variance will do the job.

Equipment you actually need

You don’t need expensive kit. I’ve seen pubs spend hundreds on “cellar management systems” that nobody uses. Here’s what actually works:

• A calibrated dipstick — £15–£30. Ask your dray driver or brewery for one. It should have volume markings specific to your keg size (50-litre, 30-litre, etc.).
• A set of digital scales — £20–£50 from any catering supplier. Accuracy to 500g is fine. This is for weighing partial kegs and open spirit bottles.
• A notebook or spreadsheet — Free. Write the date, line name, dip reading, weight, and any notes (e.g. “line changed Tuesday”).
• A till that records by line — Non-negotiable. If your EPOS doesn’t break sales down by product (Guinness, Fosters, Carling, etc.), you can’t reconcile stock. Your dray driver can also provide historical pour rates for each line to cross-check your till.

That’s it. You don’t need software, smart sensors, or a management degree. You need discipline and a system you’ll actually use.

Common mistakes in keg tracking

After 15 years, I’ve seen the same errors repeat across every pub I’ve worked with or visited. Here are the ones that cost the most money:

Mistake 1: Not recording when a line is changed or cleaned

If you don’t mark down when a keg is swapped or a line is blown through, your variance calculation is useless. A line change or deep clean uses 5–15 litres of product depending on the line length. If that’s not accounted for, you’ll think you’ve got a loss problem when you’ve actually just cleaned the pipe. Record it immediately on your stock sheet: “Guinness line changed 14:30, old keg 12L remaining, new keg full.”

Mistake 2: Checking stock only monthly or quarterly

By the time you realise there’s a problem, it’s been bleeding for weeks. Weekly checks mean you catch a 5% variance loss within 7 days, not 84 days. The difference is £50 vs £500.

Mistake 3: Not comparing till data to stock variance

If your till says you sold 100 pints but your stock check shows 80 pints gone, something’s wrong. It could be till error (more likely than you think), over-pouring, or a blocked line giving short pours. You won’t know unless you cross-check. Most pub management systems don’t do this automatically, so you have to do it manually. It takes 10 minutes.

Mistake 4: Assuming the brewery stocktaker is doing your job

The brewery stocktaker comes once a month (or quarterly if you’re unlucky). By then, a small loss has become a big one. They’re also checking your compliance with brewery agreements, not optimising your margins. Their job is not your job. Your job is to catch loss as it happens. A weekly line check catches more than a brewery stocktaker ever will because you’re measuring the same kegs every week and building a trend.

Mistake 5: Not adjusting for temperature drift

Beer expands and contracts with temperature. A cellar that drifts from 10°C to 14°C over a week will show false variance on your dip. If your cellar temperature is unstable, record it every time you dip. A 4-degree swing can account for 1–2% variance on its own.

Reconciling against till data

This is the linchpin. Your till tells you what sold. Your stock count tells you what left the cellar. They should match within 2–3%. If they don’t, here’s how to find out why:

The reconciliation process

Every Monday (or whatever day you dip), do this:

• Pull your till data for the week: pints sold by line (Guinness, Carling, Fosters, house spirit, etc.).
• Convert pints to litres (multiply by 0.568).
• Do your stock dip. Calculate litres gone from the cellar.
• Compare the two numbers line by line.
• If draught shows 50L sold on till but 52L gone from stock, that’s a 4% loss. Make a note and investigate.
• If spirits show £200 sold on till, weigh the bottles and calculate litres poured. It should match within 5%.

Keep a running sheet of these reconciliations. After 4 weeks, you’ll see patterns. If Guinness is consistently 3% light but Carling is always tight, you know Guinness has a pouring or line issue. If it’s random, you’ve got measurement error or till error.

The key: do this the same day every week. Don’t wait. The longer you wait, the more forget which line was changed, which keg was tapped, or where a problem started.

The spreadsheet vs software question

This is the question every licensee asks me: “My spreadsheet works fine. Do I really need special software?”

Honest answer: a spreadsheet can work if you’re disciplined. The trouble is, most people aren’t. A spreadsheet makes it easy to skip a week, easy to forget the formula, and easy to not add up variance properly. It also doesn’t flag anomalies. If your Guinness variance jumps from 2% to 8% one week, you want the system to tell you, not you having to eyeball it.

More importantly: spreadsheets don’t talk to your till. You’re doing the reconciliation by hand every week. For a 6-line pub, that’s 20–30 minutes of admin time. If you have data entry errors in the spreadsheet, you’ve corrupted your variance picture for the whole month.

An app or software system built specifically for pub stock control removes the manual work and gives you a trend line that makes loss or drift obvious within a week. SmartPubTools makes StockTap pub stock app, which is designed exactly for this: you log your dip readings, it pulls your till data, it calculates variance, and it flags anomalies. No subscription, no per-month fees. You buy it once and it works on any device in any cellar with a phone signal.

But here’s the non-negotiable part: whether you use a spreadsheet or software, you must do the count weekly. The tool doesn’t matter. The discipline does. I’ve seen pubs with expensive systems that nobody uses and pubs with a notebook that claw back 2 GP points in 8 weeks because they actually do the count.