Charts
Keg PSI Chart by Temperature
At 38F, carbonating to 2.0 volumes of CO2 takes about 7.2 psi, 2.2 volumes takes about 8.7 psi, 2.4 volumes takes about 10.2 psi, and 2.6 volumes takes about 11.7 psi, and colder beer needs less pressure than that for the same volumes while warmer beer needs more.
Pressure, temperature and volumes are one system
Carbon dioxide dissolves into beer according to a well established solubility relationship: colder liquid holds more dissolved CO2 at a given pressure than warmer liquid does, and higher applied pressure pushes more CO2 into solution at a given temperature. That means a target carbonation level, expressed in volumes of CO2, can be reached by many different pressure and temperature combinations, but for any one temperature there is a specific pressure that produces a specific volumes result.
This is why a keg PSI chart is always anchored to a temperature. A pressure setting that is correct for a keg sitting at 38F will overcarbonate or undercarbonate the same beer if the kegerator is actually running a few degrees warmer or colder, because the solubility relationship shifts with temperature even while the regulator's number stays the same.
Pressure needed at 38F
These four points cover the range most ales and lagers actually target, from a soft British ale at the low end to a lively American pale ale or IPA near the top. A brewer serving a beer that calls for volumes outside this range, like a wheat beer's 3.0 to 4.0 volume target, needs either a colder serving temperature, a longer conditioning time at a higher pressure, or both, since pushing straight to a high pressure at 38F and serving immediately risks pulling foam instead of beer through the faucet before the CO2 has had time to fully absorb.
| Target volumes CO2 | Pressure at 38F |
|---|---|
| 2.0 | 7.2 psi |
| 2.2 | 8.7 psi |
| 2.4 | 10.2 psi |
| 2.6 | 11.7 psi |
How temperature shifts the required pressure
The table above deliberately shows direction rather than an invented number for every temperature, because a full pressure chart across many temperatures and volumes needs a proper CO2 solubility table or calculator to compute reliably, not a short list of approximate figures. This site's keg carbonation calculator solves for the correct pressure at any temperature and target volumes combination using the actual solubility relationship rather than interpolating between a handful of anchor points.
| Change from a 38F baseline | Effect on pressure needed |
|---|---|
| Colder than 38F, same target volumes | Less pressure needed, cold beer holds CO2 more easily |
| Warmer than 38F, same target volumes | More pressure needed, warm beer holds CO2 less easily |
| Same temperature, higher target volumes | More pressure needed |
| Same temperature, lower target volumes | Less pressure needed |
Why the regulator setting and the actual carbonation can disagree
A newly kegged beer does not reach its target carbonation the moment the regulator is set. Dissolving CO2 into beer at rest takes real time at a given pressure and temperature to fully equilibrate, because gas has to diffuse from the headspace into the liquid rather than being forced in instantly. Shaking or rocking the keg speeds this along by increasing the surface area exposed to gas, but even then the beer needs some time before a pressure gauge reading translates into an actual, stable volumes of CO2 in the glass.
This is also why disconnecting a keg from gas for a period, or serving from a keg at a pressure lower than what carbonated it, does not immediately drop the beer's carbonation. The dissolved CO2 stays in solution until the beer is either poured out, warmed significantly, or left connected to a lower serving pressure long enough for gas to slowly come back out of solution and re-equilibrate with the new, lower headspace pressure.
Serving pressure and pour quality are a separate problem from carbonation
A correctly carbonated keg can still pour badly if the pressure used to push beer through the line does not match the line's resistance, since beer line length and internal diameter create friction that has to be balanced against serving pressure or the pour comes out too fast and foamy, or too slow and flat feeling at the faucet even though the beer itself is properly carbonated. That balance is a separate calculation from the carbonation pressure this chart covers, and changing serving pressure to fix a bad pour, without a matching change in line length, will eventually drift the keg's actual carbonation away from its target.
Reading the table correctly
Each row in the pressure table above describes an equilibrium condition, the pressure that, given enough time at a steady 38F, results in the beer holding that many volumes of dissolved CO2 and no more. It is not an instruction to crank the regulator to a given number and expect the beer to be ready shortly after. Reading the table as a target to hold steady over days, rather than a dial to bump temporarily, avoids the most common mistake new kegerator owners make: turning the pressure up to force-feed carbonation faster, then forgetting to turn it back down once the beer tastes carbonated enough, which slowly pushes the beer well past the intended volumes as it continues absorbing CO2 toward the new, higher equilibrium.
A dual gauge regulator makes this easier to manage correctly. The high side gauge reads the pressure remaining inside the CO2 tank itself, which matters only for knowing when the tank needs a refill, while the low side gauge reads the actual serving or carbonating pressure being applied to the keg, and that low side number is the one that belongs in this table. Confusing the two, especially on a fresh tank reading well over a thousand psi on the high side, is a common point of confusion for anyone new to kegging.
Why equilibrium takes so long, and why fixing an overshoot takes even longer
Carbon dioxide has to physically diffuse from the gas in the keg's headspace down into the liquid beer beneath it, and that diffusion happens slowly across a still, undisturbed liquid surface, which is the entire reason full equilibrium at rest can take roughly one to two weeks even once the regulator is set correctly. Agitating the keg increases the surface area exposed to gas at any given moment, which is why shaking or rocking a keg under pressure can bring a beer close to its target carbonation in a day or two instead of two weeks, at the cost of needing more hands-on attention during that time.
Reversing an overcarbonated keg is slower than creating one, because there is no equivalent shortcut for pulling CO2 back out of solution the way agitation pushes it in. The only real fix is disconnecting the gas, venting the keg's headspace repeatedly over several days, and letting the beer's own dissolved CO2 slowly diffuse back out to re-equilibrate with a now lower headspace pressure, a process that unfolds on the same slow diffusion timescale as carbonating in the first place, sometimes longer, since venting has to be repeated by hand rather than driven by a constant pressure source.
What kegerator temperature drift does over time
A kegerator that is not holding a steady temperature is quietly changing the beer's equilibrium carbonation even if nobody touches the regulator. If the thermostat drifts warmer for an extended stretch, the beer's dissolved CO2 becomes too much for the new, warmer equilibrium and some of it will tend to come out of solution, which shows up as excess foam at the tap even though the pressure setting never changed. If the thermostat drifts colder, the opposite happens, and the beer can end up holding less carbonation than intended relative to what the pressure setting was originally chosen for. A simple external thermometer or a dedicated fermentation and fridge controller keeping the kegerator at a known, steady temperature is what makes a keg PSI chart useful in the first place, since the whole chart depends on temperature actually staying where you think it is.
Everything else worth considering
SPARC Premium Dual CO2 Regulator
Two output CO2 regulator, which lets you hold two kegs at different pressures from one tank.
SPARC Gen2 Premium CO2 Regulator
Single output CO2 keg regulator with a CGA-320 inlet.
Ferroday Dual Gauge CO2 Regulator (0 to 60 psi)
Dual gauge regulator showing both tank pressure and output pressure, with a CGA-320 fitting.
Ferroday 0 to 120 PSI Dual Gauge CO2 Regulator
Higher range dual gauge regulator, useful when burst carbonating.
WELLBOM Dual Output CO2 Regulator (CGA-320)
Two output draft regulator with independent gauges.
GANCOWISE 5 lb Aluminum CO2 Tank (DOT, CGA320)
DOT approved five pound aluminium CO2 cylinder with a CGA320 valve. Ships empty and is filled locally.
TMCRAFT 5 lb CO2 Tank (DOT aluminum, CGA-320)
Five pound DOT aluminium cylinder with a CGA-320 valve, supplied empty.
Luxfer 5 lb Aluminum CO2 Cylinder (CGA320)
Luxfer aluminium cylinder, a long established cylinder manufacturer, with a CGA320 valve.
Before you do this
CO2 cylinders are high pressure vessels. Keep them secured upright, never modify a valve or regulator yourself, and have empty cylinders refilled or exchanged only through a qualified gas supplier.
Related on BrewGearCalc
Frequently asked questions
- What PSI should I set my kegerator to?
- It depends on your serving temperature and the carbonation level you want, since the same target volumes of CO2 needs a different pressure at a different temperature. At a common 38F serving temperature, roughly 7.2 to 11.7 psi covers targets from 2.0 to 2.6 volumes, which spans most ales and lagers. For a specific number at your actual temperature, this site's keg carbonation calculator solves it directly rather than approximating from a chart built around a single temperature.
- Why does my beer taste flat even though the gauge shows the right pressure?
- A regulator gauge shows the pressure being applied right now, not the beer's actual dissolved CO2 level, which can lag behind a recent pressure change by days. A keg recently tapped, recently repressurized, or served at a warmer temperature than it was carbonated at can read the correct pressure on the gauge while the beer itself has not yet caught up to that pressure's equilibrium carbonation level.
- Does a higher psi always mean more carbonation?
- At a fixed temperature, yes, higher applied pressure pushes more CO2 into solution and results in higher equilibrium carbonation. But the same psi at a colder temperature carbonates the beer more than it would at a warmer temperature, so pressure alone does not tell you the carbonation level without also knowing the temperature the keg is sitting at.
- How long does it take for a keg to reach its target carbonation?
- Left undisturbed at serving pressure and temperature, a keg typically needs on the order of one to two weeks to fully equilibrate to its target carbonation level, though this varies with pressure, temperature and headspace. Shaking or rocking the keg under pressure speeds the process considerably by exposing more beer surface to the CO2, often cutting the wait to a day or two, though it requires more hands-on attention.
- Can I over-carbonate a beer by leaving too much pressure on it?
- Yes. Beer left connected to a pressure higher than its target for long enough will keep absorbing CO2 until it reaches equilibrium with that higher pressure, ending up overcarbonated relative to the intended target. If this happens, venting the keg's headspace pressure periodically while serving at a lower, correct pressure will slowly bring the beer's dissolved CO2 back down over time.
- Is the pressure the same for every beer style at the same temperature?
- No, because different styles target different volumes of CO2 by convention. At the same 38F, a British ale's lower carbonation target needs meaningfully less pressure than an IPA's target, which in turn needs less pressure than a Belgian ale or wheat beer's higher target. The pressure always follows the volumes target, not the style name itself.
Researched from published brewing formulas, manufacturer specifications and verified owner reviews. This is general guidance, not professional advice.