Marston’s Line Check: Weekly Stock Audits That Actually Work

Last updated: 26 June 2026

Most pubs running a Marston’s estate don’t actually know their real stock position until the brewery pulls figures at the end of the month — and by then the damage is done. A Marston’s line check is a simple weekly count of every draught line, cask, and spirit bottle in your cellar, matched against till records from the same day. It takes discipline and the right routine, but it’s the fastest way to spot where money is actually leaking.

I spent five years running my own Marston’s pub on a tangle of spreadsheets and guesswork. Stock variance reports showed nothing useful, partial kegs disappeared into the ether, and spirit measures were a complete mystery. When I finally built a structured count routine — dip every cask, weigh open bottles, reconcile the same day — the weekly variance went from noise to a number I could actually trust within a fortnight. That’s when I realised what the real problem was: I wasn’t measuring stock loss. I was measuring measurement error.

This guide walks you through how to run a line check that works, what you’re actually looking for, and why the pub down the road that’s still using a spreadsheet is quietly haemorrhaging cash.

What a Marston’s Line Check Actually Is

A line check is a weekly physical count of every draught line, partial keg, and open spirit bottle in your cellar, reconciled against till records within 24 hours. It’s not an inventory count (that’s a full stocktake). It’s not a delivery check (that happens in receiving). It’s a disciplined snapshot of what you have versus what you sold.

In a Marston’s pub, you’re managing three separate areas:

• Draught lines: The beer and cider running through your font. This is where most waste lives — temperature drift, poor line cleaning, and dispenser overpour.
• Casks and kegs: Your backup stock, including partials. A 36-pint cask that’s been sat in the cellar for three weeks with no label is lost money.
• Spirits: Open bottles behind the bar. Free-pouring is the silent killer here — a 25ml measure often pours at 32–35ml if no one’s watching.

A line check measures all three against what your till says left the pub. If your till shows 47 pints of Guinness sold on Tuesday and your dipstick shows you only lost 45 pints from the keg, you have a problem. The till is the truth; the cellar is the evidence.

Why Weekly Matters (And Monthly Doesn’t)

I get this question at least twice a month: “Can’t we just do this monthly?” The answer is no, and here’s why.

If you’re losing stock and you only count once a month, you’ve got 30 days of variance to unpick. Was it the first week? The second? Which member of staff? Which line? By the time you’ve found the problem, you’ve lost three weeks of margin already. Weekly counts mean the variance is always recent — it happened in the last seven days, the same staff were working, and the till records are fresh in your head.

The primary reason to do weekly line checks is to catch variance trends before they become losses, not to punish staff after the fact. A draught line creeping up 2 pints per week might just be a temperature calibration. A spirit measure drifting 10% over five weeks is a training issue. A sudden 20% drop on a Tuesday tells you something actually went wrong on Tuesday.

Most pubs that move from a messy spreadsheet to a disciplined weekly count claw back 1–2 GP points within a couple of months. At a Marston’s pub turning over £400k a year in wet sales, that’s £4,000–£8,000 of margin you stopped bleeding. Monthly stocktakes don’t move the dial. Weekly discipline does.

There’s another reason nobody talks about: your brewery stocktaker won’t do it for you, and even if they did, it’s their job to verify your count, not to do your stock control. If you hand them a dodgy number, you’re writing off the difference.

How to Run a Line Check: The Step-by-Step

What You Need (The Kit)

You don’t need expensive equipment. I run mine with:

• A keg dipstick (£8, any cellar supplier) — for measuring beer in casks and kegs.
• A set of digital scales (£15, Amazon) — for weighing open spirit bottles. An empty bottle weighs a known amount; subtract from the full weight and you know how much is left.
• A notebook or, better, a simple spreadsheet or app — to record what you found and compare against till data.
• Your till reports — filtered by product for the same date.

You don’t need software for this, but if you’re managing more than a few lines or you get tired of chasing numbers on paper, StockTap pub stock app is built exactly for this workflow — dip, weigh, reconcile, flag variance. It stores your history so you can spot trends week to week.

The Process (Start to Finish)

Step 1: Choose your count day and stick to it.

I count every Monday morning, before service. It’s consistent, staff know to expect it, and the till data is clean. Pick a quiet time in your week.

Step 2: Dip every cask and keg on the premises.

Drop your dipstick into every active draught keg, every spare cask, and every partial. Record the pint reading. If you find a partial that’s been sat there for weeks with no label, that’s a write-off — but at least you know it’s gone. Do this methodically. Don’t guess. Dip it.

Step 3: Weigh every open spirit bottle.

Place a 70cl bottle on the scales. Note the weight. An empty 70cl bottle weighs roughly 520g; a full one weighs about 900g. If your scales show 650g, you’ve got about 9cl left. Do this for every open bottle behind the bar and in your back-up stock. It takes ten minutes if you’re organised.

Step 4: Pull till records for the same date, by product.

Most modern tills let you filter by product. Get your draught sales (by line), your spirit sales (by bottle), and anything else you’re tracking. Make sure you’re looking at the same 24-hour window as your physical count.

Step 5: Reconcile the same day.

This is the critical bit. Your till says 52 pints of Carlsberg sold. Your dipstick shows the keg lost 49 pints. Your variance is +3 pints (you have 3 pints more than expected). This could be a measurement error, a short pour, or simply a dipstick calibration issue. But now you’re looking at a number, not a question mark.

Step 6: Flag anything outside your normal range.

If your lines normally run ±1 pint variance and one draught line shows +5, investigate. Was the line cleaned? Did someone replace the font? Is the cellar temperature off? If spirits variance is more than 5%, something’s wrong — either your scales, your till data, or your pouring.

What Your Numbers Actually Mean

Here’s what nobody tells you: the number that actually matters is wet gross profit by line, not a single headline stock figure. If your Guinness line is running +2 pints variance every week and your Peroni line is running -3, your headline stock number might look flat — but you’re losing money on Peroni and (possibly) gaining on Guinness.

The reason matters, and it’s different for each type of stock:

Draught variance usually means one of five things:

• Cellar temperature creep (beer contracts/expands with temperature — off by 1°C = 2–3 pint variance per keg).
• Line cleaning waste (a full purge uses 2–3 pints per line).
• Dispenser overpour (common with older fonts or under-trained staff).
• Measurement error (your dipstick calibration drifting, or the keg sat on an angle).
• Actual product loss (leak, theft, or an unlogged spillage).

Spirit variance almost always means one of three things:

• Free-pouring drift (a 25ml measure that’s actually 32ml = 28% variance over a week).
• Forgotten wastage (spillage, a dropped bottle, a sample given away).
• Scales drift or a weighing error on your part.

Cask and keg variance usually means:

• A partial you forgot to dip or a spare cask you didn’t know was there.
• A slow keg that’s been sat so long the product degraded.
• Honest measurement error — the keg was sat at an angle, or your dipstick depth was wrong.

The point is: investigate the variance first, then decide if it’s a real loss. Most “stock loss” in a pub is actually measurement error and forgotten wastage, not theft or deliberate over-pouring. Once you know what’s real, you can fix it.

Common Mistakes That Kill Accuracy

I’ve run these checks for 15 years, and I still see the same errors:

Mistake 1: Using till reports from a different date than your physical count.

Your till says you sold 50 pints on Tuesday, but you count Wednesday. You’re comparing Wednesday’s cellar state to Tuesday’s sales. This never matches. Count and reconcile on the same day, always.

Mistake 2: Not accounting for deliveries and staff drinks.

If a new keg arrived Monday afternoon and you don’t dip it separately, your numbers are rubbish. If the lads drank four pints after lock-in, you need to account for it. Your till won’t show it. You need to.

Mistake 3: Forgetting that spirits are measured, not poured.

A till can only track spirit sales if your staff used a measure. If your measures are missing, or if a member of staff is free-pouring, the till data is fiction. Weigh the bottles and work backwards — if you sold 12 measures but only lost 8 measures’ worth of spirit, someone’s short-pouring. If the opposite, someone’s over-pouring.

Mistake 4: Dipping a keg that’s sat at an angle.

Put a keg on a flat surface before dipping, every time. The cellar floor is never level. You’ll get a 3–5 pint error if you’re not careful.

Mistake 5: Not recording your variance, so you can’t spot trends.

If you don’t write it down, you can’t see that a line is consistently creeping up or down. You’re doing the same work every week but learning nothing. Keep a simple record. SmartPubTools has a built-in cellar module that stores your history so you can compare week to week, but even a spreadsheet works if you’re disciplined.

The Real Time Investment

The question I get most: “I don’t have time to stocktake every week.”

A proper line check takes 30–45 minutes if you’re organised, and that’s including reconciliation. Dipping takes 10 minutes. Weighing spirits takes 10 minutes. Pulling till reports and comparing takes 15 minutes. If you’re running around finding bottles and keg locations, it takes longer, but that’s a cellar organisation problem, not a line check problem.

Here’s the calculus: spend 45 minutes a week now, or spend five hours at the end of the month trying to unpick where the variance came from and what went wrong. Brewery stocktakers don’t forgive sloppy records. Your GP margin doesn’t forgive untracked losses. Pick your poison.

More importantly, once you’ve done it for a month, it becomes routine. You know where everything is. You know your normal variance ranges. You’re not scrambling — you’re checking. And your staff know they’re being checked, which is worth money on its own.

The Objections, Answered

“My spreadsheet works fine.”

No, it doesn’t. A spreadsheet is a record-keeping tool, not a stock control tool. It doesn’t tell you that your Guinness line is running hot. It doesn’t flag when a spirit variance creeps outside normal range. It doesn’t store historical trend data in a way you can actually use. You’re doing the same work, but you’re not learning from it. Most pubs that move to a structured counting process (spreadsheet or app) and start reconciling weekly see variance problems surface within the first month that they never knew existed.

“Do I really need special equipment?”

A dipstick and a set of scales cost £20 total. If you don’t have them, you’re guessing at stock every week, and guessing costs money. Buy them. They pay for themselves in the first variance catch.

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

The brewery stocktaker verifies your count. They don’t do your stock control. If you hand them a dodgy number, they’ll write off the difference and charge you for it. You’re better off running your own weekly count so your number is accurate when they arrive.

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

Safety of data isn’t really the issue — it’s accuracy and usability. A spreadsheet can get corrupted. An app that’s web-based is backed up automatically. But the real difference is that a purpose-built app (like StockTap pub stock app) is built around what a pub actually needs to track: dips, weights, till reconciliation, variance flags, and trend spotting. A spreadsheet is a blank canvas — you have to build the logic yourself, and most people never do it properly. If you’ve got the discipline to build a bulletproof spreadsheet and update it weekly, you’re already in the top 10% of pub operators. For everyone else, a system built for the job works faster.