Pressure, Gas and Other Things That Hiss: Setting Up Your Regulator

A regulator turns the terrifying pressure inside a gas cylinder into the polite, beer-friendly pressure your keg actually wants. Without one, connecting a cylinder to a keg would be less like carbonating beer and more like launching it.

• DifficultyEasy
• Hands-on timeAbout 15 minutes
• You’ll needGas cylinder, regulator, gas line, gas disconnect
• Leak testSoapy water or no-rinse sanitiser

What a Regulator Actually Does #

A full CO2 cylinder sits at roughly 800 PSI at room temperature. A keg wants somewhere between 10 and 30. The regulator stands between the two like a nightclub bouncer, letting gas through only at the rate you have agreed on, and ignoring all appeals.

Most regulators have a knob or screw to set the pressure, a gauge that shows what you have set, and sometimes a second gauge showing what is left in the cylinder. Everything else is threads, washers and the quiet confidence that comes from not hearing a hiss.

Pick Your Gas, Then Your Regulator #

Choose the gas cylinder first, because the cylinder decides which regulator thread you need. Buying a regulator before a cylinder is like buying a key before you know which house you live in.

Your gas	Good for	Regulator to use
2.6kg CO2 Gas Cylinder	A kegerator or fridge setup, several kegs	MK 4 Regulator (Type 30), no adapter needed. Or a Mini 360 Core Actuator Regulator or Mini Duotight Regulator with the Type 30 Adapter for mini regulator
450g SodaStream bottle	Small kegs, the fridge, the shed (see Kegging on a Budget)	Mini 360 Core Actuator Regulator with a SodaStream Cylinder Adapter or Deluxe SodaStream Cylinder Adaptor
74g CO2 Cartridge	Portable Oxebar kegs, picnics	Mini 360 Core Actuator Regulator with the Mini 360 core adapter for 74g cartridge
2.2L Nitrogen Disposable Gas Cylinder (N2)	Nitro stouts and nitro cold brew (see below)	MK4 Regulator N2 – Type 50, no adapter needed. Or the Mini 360 Core Actuator Regulator with the Nitrogen Adapter for Mini 360 Core Regulator
16g CO2 bulbs	A quick top-up on the go	MK II Regulated CO2 Charger, no adapter needed

The Mini 360 Core turns up a lot because it swivels a full 360°, so the cylinder can sit at whatever angle fits your fridge, and with the right adapter it runs off almost any gas we sell.

Type 30 or Type 10? These are two different valve fittings used on Australian gas cylinders. They look much the same at a glance, but the threads are different, so a regulator made for one will not screw onto the other. The 2.6kg CO2 cylinders we sell are Type 30, as are most homebrew cylinders, which is why the MK 4 Type 30 is the one we usually recommend. Some cylinders from other gas suppliers use Type 10, and the MK 4 Type 10 regulator is made for those. Nitrogen uses a different fitting again, so a CO2 regulator will not fit a nitrogen cylinder. For nitrogen, use the MK4 Regulator N2 – Type 50, or the Mini 360 Core with its nitrogen adapter. The type is stamped on the cylinder valve. If you cannot read it, bring the cylinder in and we will check. It takes ten seconds and saves a second trip.

If you already have a SodaStream at home, you already own a gas cylinder. The Mini 360 Core with a SodaStream adapter is the simplest way to put that cylinder to work on a keg. We sell 450g CO2 bottles at both shops.

How the Gas Gets to Your Glass #

Gas flows one way through the system and beer flows out the other side. The gas never touches the tap, and the beer never touches the regulator, which is exactly how both of them prefer it.

Cylinder → Regulator → Gas line → Gas disconnect → Keg → Beer disconnect → Tap → Glass

Gas enters the keg’s headspace through the gas disconnect (grey, or red on Duotight) and presses down on the beer, which has nowhere to go except up the long dip tube, out the beer disconnect (black, or yellow on Duotight) and through the tap.

Hooking It All Up #

Five connections, in order, with the cylinder valve closed until the very end. Opening the gas before everything is tight is the plumbing equivalent of reading the instructions after the flat-pack wardrobe has collapsed.

1. Check the washer. Make sure there is a washer in the regulator inlet (most cylinders need one). Old, squashed washers leak. A bag of Washers for Regulators costs less than the gas you will lose.
2. Back the regulator right off. Turn the adjusting knob anticlockwise until it spins freely. This sets the output to zero, so nothing surprises you when the gas goes on.
3. Fit the regulator to the cylinder. Hand tight, then a firm snug with a spanner on full-size regulators. Not gorilla tight. The washer does the sealing, not your forearms.
4. Connect the gas line. Run gas line from the regulator outlet to a gas disconnect (grey, or red on Duotight). With Duotight fittings, push the line in firmly until it seats; cut the end square with a Tube Cutter first. A ragged cut is a slow leak waiting to introduce itself. While you are there, fit a Duotight 8mm One Way Check Valve in the gas line, fitted so gas flows from the regulator towards the keg. It lets gas through to the keg and stops beer ever finding its way back to the regulator.
5. Open the cylinder slowly. Turn the valve gently and fully. The cylinder gauge (if fitted) will jump up. The output gauge should still read zero, because you backed it off in step 2.

Now you are ready to set the pressure. Nothing should be hissing. If something is hissing, close the cylinder and go back to step 3.

Setting the Pressure #

Turn the adjusting knob clockwise slowly to raise the pressure, and watch the output gauge climb. Always set the pressure by going up to the number, not down to it. Regulators settle more accurately that way, for reasons best known to regulators.

If you overshoot, back the knob off, then briefly pull the keg’s pressure relief valve (or the regulator’s, if it has one) to let the excess out. Then come back up to the number.

What you are doing	Pressure	Notes
Seating a keg lid	About 30 PSI	A short blast, then back down
Set-and-forget carbonating	About 10–12 PSI	Keg at 2–4°C, 7–10 days
Burst carbonating	About 30 PSI	24–36 hours, then vent and drop to serving
Serving	About 8–12 PSI	Lower if foamy, a touch higher if slow
Pushing beer keg-to-keg or into a beer gun	2–5 PSI	Gentle is the whole idea

These numbers assume cold beer. Warm beer needs a lot more pressure to hold the same fizz, which is one more reason the fridge is your friend.

Exact PSI for your fridge: our keg carbonation calculator works out the set-and-forget pressure for your beer temperature.

Leak test, every time #

Spray every joint with soapy water or no-rinse sanitiser: cylinder valve, regulator, every line fitting, disconnects, keg lid and posts. Growing bubbles mean a leak. Tighten, reseat or replace the O-ring or washer, then test again.

The second test is patience: set the pressure, close the cylinder valve, and come back in an hour. If the output gauge has dropped, there is a leak you have not found yet. Leaks are why a full cylinder can mysteriously empty overnight, which is a story we hear in the shop more often than we would like.

Running More Than One Keg #

One gas cylinder can look after several kegs. You do not need a cylinder and regulator for every keg, just a couple of clever bits after the regulator you already have.

Part	What it does	You need it for
8mm Duotight 2 Way or 4 Way Manifold (with Check Valves & Isolation Valves)	Splits one gas line into two or four. Each outlet has its own on/off valve, and the check valves stop beer creeping back up the gas line into the other kegs	Two or more kegs at the same pressure
Duotight In-line Regulator with Gauge	A small second regulator that sits in one gas line, after your main regulator, and turns the pressure down for that keg only. It has its own gauge, so you can see what each keg is getting	Kegs that want different pressures, like one carbonating while another is pouring

Why check valves matter. Gas, and beer, flows from high pressure to low. Without check valves, a keg sitting at a higher pressure than the line feeding it can push gas, and sometimes beer, backwards up the gas line. That beer can end up in another keg, over-carbonating it or mixing flavours, or worse, inside your regulator, which beer is very good at ruining. It happens most after burst carbonating, or when a keg warms up. A check valve is a one-way door: gas goes into the keg, nothing comes back out. Our manifolds have them built in, so use them, and keep the valves clean.

Different pressures from one cylinder #

1. Set your main regulator to the highest pressure any of your kegs needs. If one keg is burst carbonating at 30 PSI, that is your number.
2. Split the gas with a manifold, one outlet per keg.
3. Fit an in-line regulator on each line that needs less than the main pressure, and set it to suit that keg, say 10 PSI for one you are pouring from.
4. Leak test every new joint with soapy water. More joints means more places for gas to sneak out.

An in-line regulator only turns pressure down, and it always goes after your main regulator. Never connect one straight to a gas cylinder.

Nitrogen: For Stouts That Cascade #

Nitrogen is the gas behind that slow, cascading pour and thick, creamy head you see on a pub stout. It is not a replacement for CO2. It is a second gas for a particular job, and it behaves very differently.

Nitrogen does not carbonate beer. It barely dissolves at all, which is exactly why it makes such small, creamy bubbles. Carbonate with CO2 first, then use nitrogen only to push the beer out.

What you need #

Nitrogen comes in its own cylinder with its own fitting. It is not a CO2 cylinder with different gas in it, and it needs a regulator made for it. The cylinder is the 2.2L Nitrogen Disposable Gas Cylinder (N2), and there are two regulators that fit it:

Regulator	Fits the 2.2L cylinder	Best for
MK4 Regulator N2 – Type 50	Directly, no adapter	A dedicated nitrogen setup. A full-size regulator built for nitrogen, so it can stay on the nitro keg while your CO2 regulator stays on the CO2
Mini 360 Core Actuator Regulator	With the Nitrogen Adapter for Mini 360 Core Regulator	Trying nitro, or if you already own a Mini 360 Core. Small, and it swivels to fit tight fridges

Never use a CO2 regulator on nitrogen, even if you find something that makes it fit. Nitrogen cylinders run at a much higher pressure, and nitrogen regulators are built for it.

Whichever cylinder you choose, you also need:

• NukaTap Nitro Spout. This swaps onto a NukaTap and forces the beer through tiny holes, which is what knocks the gas out into that famous cascade. Without it, nitro beer pours flat and disappointing

How to pour a nitro beer #

1. Carbonate lightly with CO2. Nitro beers want much less fizz than normal, roughly half. About 5 PSI of CO2 for a week in a cold fridge does the job.
2. Swap the gas to nitrogen. Disconnect the CO2, connect the nitrogen line (from the MK4 Regulator N2 or the Mini 360 Core) to the gas post, and set it to around 30–40 PSI. That is far higher than a normal pour, and it is meant to be.
3. Fit the Nitro Spout to your NukaTap.
4. Open the tap fully and pour hard, straight down into the glass. Then wait. The cascade is the show, and the head settles into place over a minute or so.

Good candidates: stouts, porters, Irish reds, and cold brew coffee (non-alcoholic, and spectacular on nitro). Hoppy pale ales and lagers are better on plain CO2, because nitrogen softens the hop aroma and the crispness.

Pure nitrogen at high pressure slowly pulls some CO2 back out of the beer, so a nitro keg is best enjoyed over a few weeks rather than a few months.

The 2.2L nitrogen cylinder is disposable and cannot be refilled, so when it is empty you replace it with a new one. Only fit the MK4 Regulator N2 – Type 50, or the Mini 360 Core with its nitrogen adapter.

Pressure Relief Valves: The Little Ring You Pull #

Every keg lid has one, and so do some regulators, such as the MK 4: a small valve with a ring on top, usually called a PRV. It has two jobs. Pull the ring and it lets gas out when you want it to, which is how you purge air from a keg or vent it after carbonating. Leave it alone and it is a safety valve: if the pressure ever climbs too high, it opens by itself and lets the excess out before anything else gives way.

The colour tells you roughly the pressure at which it opens on its own:

Colour	Opens at about
Yellow	17 PSI
Red	35 PSI. The most common one on ball lock kegs
Green	65 PSI. The one fitted to the Oxebar 20L PET keg
Grey	100 PSI

Why the different ratings? A relief valve has to open before the thing it protects is in any danger, so each keg, fermenter or regulator is fitted with one to suit it. Serving pressure is only around 10–12 PSI, so in normal use none of them should ever open by themselves.

Replace a PRV with the same colour that came fitted. Never swap in a higher-rated one to stop it hissing. If a relief valve keeps opening on its own, the pressure is too high, and that is the problem to fix, not the valve.

Relief valves are not precise: they can open up to about 10 PSI either side of their rating. Dried beer or sugar can also make them stick, so give the lid valve a rinse every time you clean the keg. For holding an exact pressure, such as when fermenting, you want a spunding valve instead. That is covered in Under Pressure: Pressure Fermenting.

Safety and When Things Go Wrong #

CO2 is not dangerous in the way that fire is dangerous. It is dangerous in the way that quietly filling a small room is dangerous. Treat the cylinder with respect and it will treat your beer with fizz.

• Keep cylinders upright and secured so they cannot fall. A falling cylinder can snap its valve.
• Never leave a cylinder in a hot car or in direct sun. Pressure rises with heat.
• Store and use gas in a ventilated space. If a large leak happens in a small room, open up and step outside.
• Never connect a cylinder to anything without a regulator in between.
• Close the cylinder valve when the system will sit unused for a while.

Problem	Likely cause	Fix
Output gauge creeps up on its own	Regulator not settling, or set by coming down	Back off and set again by coming up to the number
Gas runs out far too fast	A leak	Soapy-water test on every joint; replace washers and O-rings
Hiss at the cylinder	Missing or worn washer, or loose fitting	Close the valve, replace the washer, refit
Line pops out of a Duotight fitting	Cut not square, or line not fully pushed in	Recut square with the Tube Cutter and push home firmly
Beer in the gas line or regulator	Keg pressure higher than the gas line, often after burst carbonating	Vent the keg before turning the regulator down, and fit a Duotight 8mm One Way Check Valve in the gas line
No gas reaching the keg	Cylinder valve closed, or knob backed right off	Open the valve fully; turn the knob clockwise

If you get stuck, bring the whole setup into Nerang or Oxenford, or send us a photo and a message. We can usually spot a missing washer from across the counter.

Happy brewing, and may the only hiss you ever hear be the one from the tap.