Short on beer gas? Check your pints per cylinder, find the leak, and keep the taps that pay running

The government says the UK's CO2 supply has failed three times now, in 2018, 2021 and 2026, and each time it's needed bailing out. If your gas deliveries have been moving about, that's why. A 6.35kg cylinder should push about 1,200 pints on a system that's running right, and even after this autumn's price rise the gas is still only about 3.5p a pint. So the gas isn't the cost. Running out is. The cheapest thing you can do this week is find out how many pints you're actually getting per cylinder, because a leak can take a third of it and you'd never see it anywhere else.

When gas goes short the instinct is to ring round suppliers. That mostly doesn't work, for reasons I'll get to. What does work is wasting none of what you've got and moving a few products onto things that don't need gas at all. Here's how I'd go about it, in the order I'd do it.

Why the gas keeps running short

Food-grade CO2 isn't made for pubs. It's mostly a by-product of fertiliser and ammonia plants, plus some bioethanol, so when those plants slow down because gas prices are high, our supply tightens whether or not anyone in the drinks trade wants it to. The government's call for evidence in June 2026 spelled it out: most UK demand is now imported, domestic production makes only a small contribution, a few large distributors dominate the market, and in April 2026 it stepped in to support the restart of a mothballed bioethanol plant to keep critical supplies going.

That last bit is why switching supplier rarely helps. Inn Express told its customers in August that it had approached multiple alternative gas suppliers and none could help, because a different name on the cylinder doesn't change where the gas comes from. As I write this on 15 October, its website still carries a gas shortage notice across every page. Treat any delivery date as an estimate until the cylinder's in your cellar.

First job: how many pints are you getting per cylinder?

Adams Gas puts a 6.35kg CO2 cylinder at about 1,200 pints on an efficient system, which is 5.26 grams of gas a pint. That gives you a yardstick, and almost nobody checks against it. Here's how:

1. Write the date on the tag each time you change a CO2 cylinder.
2. Between two changes, add up the draught pints sold through the lines on that gas. Your till's product sales report gives you this, or your stocktake if you count weekly.
3. Divide by the cylinder size. That's your pints per cylinder.

Cylinder	Pints you should get (efficient system)	If you're getting 760
6.35kg CO2	About 1,200	63% of what you should, so roughly a third of your gas is going somewhere other than beer
15kg CO2	About 2,850	n/a

The 1,200 is Adams' figure. The 2,850 for a 15kg is my arithmetic at the same 5.26g a pint, and the 760 is just an example. Long lines, a warm cellar and tired kit all pull the real number down, so don't panic over 1,050. But if you're well under three-quarters of it, I'd be looking for a leak before I worried about the next delivery. Adams' own advice is the same: unusually high gas use or regularly running out usually means a leak or the wrong pressure, and a qualified cellar technician should find it.

Two things you can check yourself first. Brush soapy water round every coupler, joint and regulator connection and watch for bubbles. And look at where your regulators are set. Pressure that got turned up months ago to cure a fobbing line is often still sat there. Fobbing is usually temperature, a dirty line or a nearly empty keg, and more gas doesn't fix any of them.

Gas follows pints, so don't expect miracles from pulling a slow line

Every pint pushed out of a keg has to be replaced by gas, and on top of that you lose whatever leaks from that line's couplers. So a line selling 30 pints a week uses about a tenth of the gas of one selling 300. Taking the slow line off saves you its share of the leaks and a little gas. It doesn't free up much for your main lager. What it does save is the slow line's other costs, the cleaning waste and the ullage, which my draught lines guide works through. If a line was already marginal, a shortage is a good excuse to move it onto packaged. Just don't expect it to rescue your gas.

The bigger wins come from products that use no gas at all.

What to switch, and what it costs you

Move	Gas saved	What it costs you
Get the handpulls going again	All of it on that line. A handpull draws air in through the spile, it doesn't use gas	Cask needs turnover and someone who knows how to look after it. A firkin is 72 pints and wants selling in about three days once it's on
Take cask breathers off	The breather's gas	Shorter cask life, so only where the cask sells fast. My cask breather guide has the trade-off
Put bag-in-box cider on a spare cask line	A whole keg line's worth	Lines need cleaning and setting up properly first. Talk to whoever looks after your cellar
Switch the post-mix off and sell packaged soft drinks	The gas your carbonator uses, which can be a decent chunk in a food-led pub	Post-mix makes more per glass than bottles. A 330ml glass Coca-Cola costs about £1.16 before VAT from a wholesaler, a 330ml can about 67p
Keep the lines that pay	Nothing on its own	Nothing. It just makes sure the gas you have goes where the money is

The cask and cider ideas come straight from Inn Express's own advice to its customers, which is good, and it says the post-mix switch usually stacks up where beer pays the bills, because a bottle at a weaker GP still goes through the till and a dead lager tap doesn't. I agree with that. If you do switch, get the soft drinks set up as products in your stock system and on the till before the first bottle sells, or you'll have a soft drinks variance in a month's time that's really a till button problem.

What I wouldn't do: run a stout or a beer that's meant to be on mixed gas on straight CO2 because that's what turned up. Use the gas the brewer specifies. Over-carbonated stout fobs, and fobbing is beer down the drain, which is the expensive kind of waste. And don't push beer with a workshop compressor. Proper air-dispense kit exists, with filters and pressure control, and it suits a garden or function bar keg you'll empty in a session. An air line on a keg coupler puts oxygen straight into the beer and spoils the rest of it.

How much gas to hold

Adams Gas says hold one and a half times what you get through in a week. That's a normal-times rule. When dates are moving, I'd want two weeks in the cellar if your supplier's cylinder rental makes it affordable, because the cost of a spare cylinder is nothing next to a dead lager tap on a Saturday. Work out your weekly use from the pints-per-cylinder check above. A pub selling 600 pints a week through CO2 lines gets through about half a 6.35kg cylinder a week.

And send your empties back. Inn Express made the point that empty cylinders sitting in yards and cellars are gas nobody can get to. If you've got two empties behind the bins, they're slowing down your own next delivery.

What it costs now

I priced cellar gas for my cellar gas guide on 8 September. Same supplier, same products, checked again on 15 October:

Cylinder	8 September 2026	15 October 2026	Gas per pint now
CO2 6.35kg	£39.38	£41.75	About 3.5p
CO2 15kg	£89.80	£95.18	About 3.3p
30/70 mixed gas 20L	£54.52	£57.79	n/a

That's about 6% up in five weeks at the listed prices. Still pennies a pint. Your own supplier's prices and deposits will differ, and some charge monthly rental instead of a deposit, so check your invoices.

What a gas shortage does to your stocktake

What to watch for at the next count.

A tap that's been off for a few days still has a keg on it. That's fine as long as it's still in date, but count it, and if it's gone past its best because it sat too long, log it as wastage with the reason. If it's a full unopened container, my ullage guide explains when your supplier will credit it.

Meddling with pressures shows up as yield. If you turned the gas down to stretch a cylinder and the lager went flat, or up and it fobbed, the beer you poured away is in the variance. Write it in the wastage log the same day so the stocktake has an explanation.

Switching products moves the GP. Bottled soft drinks instead of post-mix will drop your soft drinks GP, and cask instead of a keg line changes your draught mix. That's a real change in margin, not a loss, and you want your stocktake to show it as one. If you're using StockTap, set the new products up with their cost prices and they'll sit in the GP report from the first count. On paper, give them their own lines.

A safety note while you're down there. CO2 pools in a cellar that isn't ventilated well. A CO2 monitor on the wall, cylinders upright and chained, and anyone changing them knowing what they're doing. That matters more than any of the money in this guide.

My take

Gas is the cheapest thing in the glass and the one thing that can close half your bar. You can't fix the supply. You can find out this week whether you're getting 1,200 pints a cylinder or 760, sort the joints if you're not, get the handpulls and a box of cider working, and send the empties back. If the shortage eases next month, all of that still saves you money.

Common questions

Why is there a CO2 shortage for pubs in 2026?

Food-grade CO2 is mostly a by-product of fertiliser, ammonia and bioethanol production, and those plants have cut back. The government's June 2026 call for evidence says most UK demand is imported, a few distributors dominate the market, and supply failed in 2018, 2021 and 2026, each time needing intervention.

How many pints should a CO2 cylinder pour?

About 1,200 pints from a 6.35kg cylinder on an efficient system, or 5.26 grams per pint, per Adams Gas. A 15kg cylinder works out at about 2,850 pints at the same rate. Long lines, a warm cellar and worn equipment reduce it. Well under three-quarters of that usually means a leak or the wrong pressure.

How can a pub make its beer gas last longer?

Check pints per cylinder to find leaks, brush soapy water round joints, reset regulators that have crept up, use handpulls for cask, put bag-in-box cider on a cask line, and consider switching post-mix soft drinks to packaged, since post-mix carbonation uses CO2 too.

Does post-mix use CO2?

Yes. Carbonating soft drinks at the bar uses CO2 all day, and in a food-led pub it can be a decent share of what you get through. Switching to bottles and cans saves that gas but costs margin, because post-mix makes more per serve than packaged.