How to check a keg level indicator

Last updated: 29 June 2026

Most pubs have kegs sitting in the cellar that nobody actually knows the contents of until they’re empty. You’re relying on memory, a sticky label, or worse — guesswork — to know when to order the next one. That’s a problem, because the stock you can’t measure is the stock you’ll lose. A 1% shortfall on wet sales quietly costs a typical pub £3,000–£5,000 a year, and it starts with kegs nobody checked properly.

If you’re running a pub and you want to know what’s actually in those casks and kegs before you run out, or before you get a nasty surprise at stocktake, you need to know how to read a keg level indicator the right way. Most landlords don’t — they just tap the side, listen for a hollow sound, and hope. That’s why variance goes unnoticed until it’s too late.

In this guide, I’ll walk you through the three methods that actually work, show you why they matter more than the brewery’s count, and explain what to do when your numbers don’t match what your till is telling you.

Why Keg Level Indicators Matter in Your Pub

The most effective way to stop stock loss in a pub is to measure what you have every single week — not just when you run empty, and not just when the brewery does their own count. When you skip that step, you’re flying blind on the one number that tells you whether you’re making money on draught.

I spent years running my own pub on a tangle of spreadsheets, still losing track of partial kegs and spirit measures. Once I built a simple routine around a dipstick and a set of scales, my weekly variance went from guesswork to a number I could trust within a fortnight. The difference wasn’t complicated — it was just consistent measurement.

Here’s what most people don’t realise: draught beer hides losses in three places. Bad cellar temperature causes slow leaks. Poor line cleaning wastes product down the drain. And most so-called ‘theft’ is actually measurement error and forgotten wastage. If you’re not checking your keg levels the same way every week, you’ll never know which one is costing you.

The number that actually matters is wet gross profit by line, not a single headline stock figure. If you’re only looking at “we’re down 2% on beer this month”, you’ve already missed the opportunity to catch where it went.

The Three Ways to Check a Keg Level

There are three methods that work. Two of them are reliable. One is mostly marketing. Here’s how to tell them apart.

1. The Dipstick Method

Fastest, most practical, works for 99% of standard beer kegs.

2. The Weight Method

Most accurate for partial kegs and open spirit bottles. Requires scales.

3. Manufacturer Indicators

Useful as a backup check, but often inaccurate and can’t be relied on as your primary method.

I’ll show you exactly how to use each one, and when to use them.

The Dipstick Method: Most Accurate for Draught Beer

This is what I use in my own pub every Friday morning, and it takes about 90 seconds per keg. A keg dipstick works by measuring the depth of liquid inside the container, converting the depth reading to a volume using the keg’s internal dimensions.

What you’ll need:

• A standard keg dipstick (£8–15 from any brewery supplier)
• A clean, dry cloth
• A pen and paper, or better — a logging app like StockTap pub stock app
• 5 minutes per keg

How to do it:

1. Locate the dip tube. Every keg has a tube running down the inside centre. On UK kegs, the dip tube opening is usually at the top, just inside the rim.
2. Lower the dipstick slowly. Push the stick straight down until you feel resistance (the bottom of the keg). Don’t force it.
3. Mark the liquid level. Some dipsticks have a float that marks automatically. If yours doesn’t, note where the stick comes out wet.
4. Read the volume. Pull the stick out. Most dipsticks have graduations printed on the side. Read it at eye level — don’t angle it.
5. Log it immediately. Write down the keg code, line, date, and volume. This matters more than you think — a gap of even two hours can make you forget what you actually counted.

Why this works: You’re measuring the actual depth of liquid, which equals volume. It’s mechanical, fast, and it’s the same method breweries use for their own stock control. The downside is it only works if the keg is standing upright and at rest — if your keg is on a tilt or the cellar is vibrating, the reading won’t be accurate.

Common mistakes: The biggest one is not pushing the stick all the way to the bottom. If you stop too early, you’ll overestimate how much is left. The second is not letting the stick settle before you read it — if liquid is still running down the stick, the reading is wrong.

The Weight Method: Best for Accuracy on Partial Kegs

For spirit bottles and partial kegs that have been open for days, the weight method is more accurate than visual inspection. The weight method works by comparing the current weight of a container to its known empty weight, with the difference equalling the volume of product inside.

What you’ll need:

• A set of digital scales accurate to 50g (£20–40)
• The empty weight of each keg (ask your brewery or measure a known-empty one yourself)
• A baseline weight chart for your stock (e.g. a full 30L keg weighs roughly 40kg, a full bottle of spirits weighs roughly 1.2kg)

How to do it:

1. Get the keg on the scales. If it’s too heavy to lift onto your till scales, use a bathroom scale on the floor — they’re accurate enough for stock control.
2. Read the weight. Note it down to the nearest 100g.
3. Subtract the empty weight. If the keg weighs 28kg and empty it weighs 8kg, you have 20kg of product. At roughly 1kg per litre, that’s about 20 litres left.
4. Cross-reference your dipstick reading. The two should be within 1–2 litres of each other. If they’re not, something’s leaking or you’ve made a measurement error.

Why this works: Weight doesn’t lie the way visual checks do. A keg that looks half-full might actually be 40% or 60% full depending on the angle and the light. Weight is absolute.

When to use it: Every time you open a spirit bottle for the first time, weigh it. When a keg has been sitting in the cellar for more than a week, weigh it as well as dipping it. If you’ve had a suspected leak or a line issue, weighing the keg before and after a service call gives you a number for the wastage.

Manufacturer Indicators: What They Tell You (and Don’t)

Most modern kegs come with some kind of level indicator built in — a float, a gauge, a window, or a click-counter on the valve. They’re convenient, and they look official. But here’s the reality: they are not a substitute for a dipstick or scale measurement and should only be used as a secondary check.

Why they fail:

• Floats stick if the keg hasn’t been moved in weeks.
• Gauges lose accuracy once a keg has been on tap for a while.
• Click-counters are often misaligned or damaged in transit.
• They’re calibrated for full kegs, not partial ones — the margin of error gets wider the emptier the keg is.

I’ve seen a manufacturer gauge read “3 pints left” when the keg actually had 8 litres. That’s not good enough if you’re trying to reconcile your till to your stock.

Use them as a quick visual check in the morning. “Is this keg still serviceable or is it nearly done?” That’s fine. But for your actual weekly count, use the dipstick or the scales.

Reconciling Your Counts to Your Till Data

Here’s where most pubs drop the ball. You do a brilliant job checking your kegs on a Friday morning. But if you don’t reconcile that count against what your EPOS says you sold on Friday, the whole exercise is pointless.

This is the routine that actually catches losses:

1. Do your keg count. All kegs, all partial bottles, same time every week.
2. Log it the same day. Don’t wait until Monday.
3. Pull your till data for the same period. How many pints of Guinness did you ring through last week?
4. Calculate your expected usage. If you sold 140 pints of lager at 568ml per pint, you should have used roughly 80 litres.
5. Compare to your actual stock movement. Did your kegs go down by 80 litres? Or 75? Or 90? The difference is your variance.
6. Investigate the gap. If you’re consistently 5 litres down, that’s waste or over-pouring. If it’s 15 litres, that’s a problem — either your measures are wrong, your line is leaking, or the till is ringing through incorrectly.

Most pubs that move from a messy spreadsheet to a disciplined count like this claw back 1–2 gross profit points within a couple of months. That’s real money. The catches happen because you spot the pattern before it becomes a £3,000 annual loss.

This is exactly what SmartPubTools was built to handle — turning weekly keg counts into a real financial picture you can act on. But the principle works whether you’re using an app or a notebook: measure, log, reconcile, investigate.

Frequently Asked Questions

How do you read a keg level indicator on a dip tube?

Lower the dipstick straight down the dip tube until it hits the bottom of the keg. Pull it out and read the graduation mark where the stick comes out wet. Record the volume immediately. Most readings take 30–60 seconds per keg.

What’s the difference between a full keg and an empty keg weight?

A standard 30-litre UK keg weighs roughly 8–10kg empty and 38–42kg when full. The difference (28–32kg) tells you how much product is inside. Always weigh the empty keg first to get your baseline, or ask your brewery for the specification.

Why do keg level indicators sometimes give different readings?

Different methods measure different things. Dipsticks measure depth. Scales measure weight. Manufacturer gauges are often inaccurate. Use dipstick and scales together — they should agree within 1–2 litres. If they don’t, something’s leaking.

Should I check keg levels weekly or just when I run out?

Weekly. Checking only at empty means you’ve missed weeks of potential loss and can’t pinpoint when it started. A weekly dip also tells you when to order before you run dry, preventing service failures.

Is weighing a keg more accurate than using a dipstick?

For partial kegs that have been sitting for a week or longer, yes — weight is more reliable than a dipstick reading. For fresh kegs on active lines, a dipstick is faster and just as accurate. Use both for the most complete picture.

Keg counts only matter if you’re tracking them consistently and reconciling them to till data every single week.

Most pub spreadsheets fail because they’re missing the second half of this equation — the link between what you counted and what you actually sold.

StockTap is built by a working pub landlord specifically for this. Log your keg counts in 3 minutes, reconcile to till data automatically, spot variance patterns in real time. £97 once, no subscription, works on any device.






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