How to Measure a Keg for Stocktaking

Last updated: 29 June 2026

Most pub licensees measure keg stock using nothing more than a tap on the barrel and a hopeful guess. The problem: you’re losing money every single day and you don’t know it. A 1% stock loss on wet sales quietly costs a typical pub between £3,000 and £5,000 a year, and draught losses hide themselves better than spirits because nobody can see what’s actually in a sealed keg. The good news is that measuring a keg for stocktaking doesn’t require expensive equipment or a degree in logistics — it requires a system, discipline, and the right measurement method. This guide shows you exactly how to measure a keg accurately, what tools you need, and how to reconcile your count against your till data so you catch losses before they become expensive habits. By the end, you’ll have a repeatable process that takes 15 minutes per week and gives you numbers you can actually trust.

Why Accurate Keg Measurement Matters

You read your till roll every night and think you know your sales. You don’t. Your EPOS tells you what left the bar. It doesn’t tell you what never made it to the glass. That gap is where most pub losses live — and draught beer loss is the hardest to see because you’re not counting individual bottles or optics. You’re guessing at what’s left in a sealed barrel.

The number that actually matters is wet GP by line, not a single headline stock figure. Spirits hide losses in over-pouring (a free-poured 25ml is often 32–35ml in reality), draught hides it in poor cellar temperature and bad line cleaning waste, and most stock ‘theft’ is actually measurement error and forgotten wastage. If you’re not measuring your kegs consistently and comparing the result against what your till says sold, you’re flying blind.

At my own pub I was running stock on a tangle of spreadsheets and still losing track of partial kegs and spirit measures. I built a simple count routine around a dipstick and a set of scales, and the weekly variance went from guesswork to a number I could trust within a fortnight. Within two months, I’d clawed back just over 1 GP point by finding — and stopping — waste I couldn’t see before. That’s real money in a tight margin business.

The Dipstick Method: Your Primary Measurement Tool

A dipstick is a calibrated rod marked in litres that you drop into a cask or keg to read the volume remaining. It’s the industry standard because it works — provided you use it the same way every single time.

What You Need

• A calibrated dipstick matching your keg type (ask your brewery rep — they’ll often supply them free)
• A clean, lint-free cloth to wipe the stick after each read
• A notebook or digital form (paper is fine; consistency is the point, not technology)
• A torch if your cellar is dark

The Correct Dipstick Technique

The most important rule: measure the same keg the same way every single week. Here’s the method:

1. Make sure the keg is level. A tilted keg gives a false read. Level the cellar floor, or use a shim. This matters more than people think.
2. Open the shive (the hole at the top of the keg) carefully. Don’t let air rush in aggressively; a controlled vent prevents foam.
3. Drop the dipstick slowly into the centre of the keg. It should fall freely without catching the sides. If it sticks, the keg isn’t level.
4. Let it rest on the bottom for two seconds. Don’t force it or move it around — just let it settle.
5. Lift it straight out and read the wet line immediately. The meniscus (the curve of liquid on the stick) marks the surface. Read at eye level, not from above or below.
6. Record the figure and the date in your stock sheet. Write down the keg code, the line name, the volume, and today’s date. Every single time.
7. Wipe the dipstick clean with a dry cloth before the next keg. Residual beer left on the stick will make the next reading inaccurate.

Measure your kegs at the same time of day each week — ideally mid-morning on the same day. Sales fluctuate during the week, so a Wednesday count and a Friday count on the same keg will be different. Fixing a measurement day removes that variable.

Backing Up Your Dipstick with Weight Checks

A dipstick gives you volume. A set of scales gives you a second opinion, and it catches mistakes your eyes missed.

A commercial kitchen scale works by measuring the difference between the keg’s tare weight (empty) and its current weight, which tells you the volume of liquid inside. This is your verification tool. You don’t need to weigh every keg every week — but you should weigh at least one keg per line every fortnight to confirm your dipstick is reading consistently.

How to Use Scales

• Use a platform scale rated for at least 50kg (most kegs full weigh 40–50kg)
• Record the tare weight of each empty keg on the keg itself (use a waterproof label). This is your baseline.
• Each week, weigh the partially full keg and subtract the tare. The difference in kg is roughly equivalent to litres.
• Compare the weight-derived volume to your dipstick reading. They should match within 1–2 litres.

If your dipstick says 15 litres but the scales say 10 litres, your dipstick isn’t level or the keg isn’t level. Re-measure. If they still don’t match, stop using that keg for important lines until you’ve worked out why.

Reconciling Keg Stock Against Till Data

Your measurement is worthless if you don’t compare it to what actually sold. This is where most pubs fail. They measure their kegs, write down the numbers, and never look at them again. Your till tells you what your customers bought. Your stock count tells you how much liquid left your cellar. These two numbers must match — and if they don’t, that gap is your loss.

The Weekly Reconciliation Process

1. Pull your till report for the week and isolate draught sales by line. Your EPOS should break this down. If it doesn’t, you need a better EPOS.
2. Calculate your expected usage. If your till says you sold 47 pints of Guinness this week, and a pint is 0.568 litres, you should have dispensed 26.7 litres. Add 10% for wastage (line cleaning, foam, spillage). You should have used roughly 29 litres.
3. Compare against your keg measurement. If you measured the keg at 38 litres last week and 12 litres this week, you used 26 litres. That’s 3 litres short of expectation — or 10% loss, which is normal line loss. Fine.
4. If the gap is more than 15%, investigate. Did the line get cleaned? Did someone forget to log a keg change? Is the cellar temperature out of range?
5. Do this reconciliation the same day as your measurement, while the numbers are fresh. Recording Friday’s measurement on the following Tuesday guarantees you’ll forget what happened.

This is where the StockTap pub stock app becomes useful — it holds your measurement data, calculates expected usage automatically, and flags variances so you don’t have to hunt for them in a spreadsheet. But a notebook and a calculator will do the same job if you’re disciplined about it.

Common Mistakes That Hide Losses

I’ve made all of these. Most licensees do.

Measuring at Different Times Each Week

If you measure Monday one week and Thursday the next, your variance figures are meaningless. Sales patterns change day-to-day, so a Monday keg level and a Thursday keg level on the same line will differ naturally. Fix a measurement day and stick to it.

Not Re-levelling Your Kegs

A keg tilted by even half an inch gives a dipstick reading that’s off by 2–3 litres. That sounds small until it happens every week and you’re 100 litres out at month-end. Check cellar floor levels regularly. Use a spirit level. Sounds fussy — it’s not.

Forgetting to Record Keg Changes

You measure a keg at 8 litres on Friday. Monday morning someone else changes it and doesn’t log it. When you measure Monday evening, you see 40 litres and think there was gain — then you panic and re-measure, and lose an hour. Record every keg change the moment it happens. A Post-it note on the cellar door works; so does a line in your notes app.

Ignoring Cellar Temperature

A warm cellar causes more foam, more spillage, and more perceived loss. A cold cellar causes too much carbonation and too much waste during line cleaning. Neither is your fault as a licensee, but both affect your measurements. Check your cellar thermometer every time you measure. A reading between 12–14°C is ideal.

Not Checking Your Scales

A faulty scale is worse than no scale. Weigh something you know the weight of — a 20kg bag of sugar, or a 50kg sack of flour from your supplies — once a month. If it’s off by more than 500g, your scale is drifting and you need to recalibrate or replace it.

Building a Weekly Keg Measurement Routine

The reason most pubs don’t measure kegs properly is not because the method is difficult — it’s because they’ve never built it into a routine. Routine makes it automatic. Here’s how I do it at my pub.

Your 15-Minute Weekly Routine

Every Wednesday morning at 10 a.m., I spend 15 minutes measuring every cask and partial keg in my cellar. The routine is:

• Walk the cellar with my dipstick and my measurement form
• Measure each keg in the same order every week (left to right, top to bottom — order doesn’t matter, consistency does)
• Record the line name, keg code, volume, date, and cellar temperature
• Note any changes: keg swaps, line cleans, anything out of the ordinary
• Take a photo of the form on my phone

Wednesday afternoon (while I’m between services), I pull my till report, calculate expected usage by line, and compare it to my measurement. If a line is more than 15% out, I add it to a note and think about it over the weekend. By Monday, I’ve usually worked out what happened.

By doing this every single week, I catch drift before it becomes a problem. A 1-litre loss per line per week adds up to 52 litres a year on a single line. Multiply that by four lines and you’re back to the £3,000–£5,000 loss figure. But if I’d caught it in week two, I’d have fixed it in week three and lost nothing.

Most pubs that move from a messy spreadsheet to a disciplined weekly count claw back 1–2 GP points within a couple of months. That’s not because the spreadsheet was wrong — it’s because you weren’t actually using it. A routine makes measurement automatic, which makes loss visible, which makes correction possible.

What Temperature Should Your Cellar Be?

Between 12–14°C is ideal for cask ale. Between 2–4°C for lager. Most electronic thermometers give a false reading if you place them on a keg (the metal conducts temperature unevenly). Mount your thermometer on the cellar wall, away from direct sunlight or heating pipes, and record it every time you measure.