The Force Carbonation Chart
The intersection of temperature, pressure, and time. Dial in the perfect fizz for your draft system.
Why We Use The Chart
Force carbonation is the act of infusing (“forcing”) carbon dioxide (CO2) into your beer from a gas cylinder, rather than waiting for yeast to produce it naturally in the bottle.
However, CO2 doesn't just dissolve magically; it obeys the laws of physics—specifically Henry's Law.
The Golden Rule: Colder liquids hold gas better than warmer liquids.
This implies that setting your regulator to "12 PSI" doesn't mean anything unless you know the temperature of your keg.
At 35°F, 12 PSI might give you a perfect Pale Ale.
At 45°F, that same 12 PSI will result in flat, lifeless beer. This chart is your map to navigating that relationship.
How to Use This Chart
- Measure Temperature (Y-Axis): Determine the exact temperature of your beer inside the kegerator or keezer. Do not guess; use a calibrated thermometer in a glass of water stored inside the fridge. Find this number on the left vertical column.
- Select Desired Volumes (Color): Look for the colored zone that matches your beer style (e.g., Green for a Pale Ale). The number inside the cell represents "Volumes of CO2."
- Find the Pressure (X-Axis): Trace up from your desired carbonation level to the top row to find the required PSI setting for your regulator.
- The "Set and Forget": Set your regulator to that PSI number, hook up the gas, and leave it alone. In approximately 10-14 days, the beer will absorb the gas until it reaches equilibrium.
Pressure (PSI) vs Temperature (°F)
Under-Carbonated
0 – 1.49 Volumes
At this level, beer is often perceived as "flabby" or lifeless. Without the prickly sensation of carbon dioxide (carbonic acid), the beer can taste watery or confusingly syrupy, as there is nothing to scrub the sweetness from the tongue.
When is this desirable? This range is appropriate for traditional English Cask Ales (Real Ale), which are vented to the atmosphere and served at cellar temperatures. It is also common for still meads, heavy Barleywines meant for decades of aging, or unblended Lambics served straight from the barrel.
Stouts & Porters
1.50 – 2.19 Volumes
Low carbonation is essential for a creamy, smooth mouthfeel. High levels of CO2 create carbonic acid, which tastes sharp and bitter; in a dark beer that already has bitterness from roasted malts, high carbonation would make it taste acrid and thin. Keeping the volumes low allows the rich chocolate and coffee notes to coat the palate.
Serving Note: This is the range for "Nitro" style beers (like Guinness), although those use a Nitrogen blend to push the beer. If serving on pure CO2, keep the pressure low and the temperature slightly warmer (50-55°F) to appreciate the malt complexity.
Most Ales & Lagers
2.20 – 2.59 Volumes
The "Green Zone" covers 90% of commercial and craft beers. This level provides the standard crisp, refreshing "bite" we associate with a cold pint. It is high enough to form a rocky, lasting foam head (1 inch), which traps hop aromas, but not so high that it creates bloating.
Style Fit: American Pale Ales, IPAs, Ambers, Pilsners, and Kolsch styles thrive here. The carbonation acts as a palate cleanser, scrubbing fat (from burgers or pizza) off the tongue, readying you for the next sip.
Wheat, Lambic, Saison
2.60 – 4.0 Volumes
High effervescence is a defining trait of these styles. The bubbles act as an elevator for aroma, vigorously driving volatile esters (like the banana/clove in Weissbier or the funk in Saison) out of the glass and into your nose.
The mouthfeel is often described as "mousse-like" or "spritzy."
Draft Warning: Dispensing beer at this pressure is difficult on standard setups. You will likely pour a glass of pure foam unless you use significantly longer beverage lines (10-12 feet) or a flow-control faucet to increase resistance.
Over-Carbonated
4.01+ Volumes
Beyond 4.0 volumes, you enter the danger zone.
Standard glass bottles can explode, and kegs become difficult to manage. The sensory experience is unpleasant: an aggressive acidic burn that masks malt sweetness and hop nuance.
Exceptions: Only highly specialized Belgian Golden Strong Ales (like Duvel) or Champagne-style beers venture here, and they require heavy-duty bottles and specialized cork-and-cage closures to contain the immense pressure.
Beyond the Chart: Essential Adjustments
1. The Altitude Factor
Most regulators measure "Gauge Pressure" (PSIG), which assumes you are at sea level. If you live at high elevation, the atmospheric pressure is lower, meaning your gauge is lying to you slightly.
Rule of Thumb: Add 1 PSI for every 2,000 feet (600 meters) of elevation above sea level.
Example: If you live in Denver (5,280 ft) and the chart says 12 PSI, set your regulator to roughly 14.5 PSI.
2. The Balancing Act (Foam Control)
Using the chart to carbonate is step one. Getting it into the glass without a cup full of foam is step two. If you carb a Hefeweizen to high pressure (3.5 Volumes / 20+ PSI) but use a standard 5-foot serving line, you will pour pure foam.
The Fix: Higher pressure requires more resistance. You accomplish this by using longer beer lines. A highly carbonated beer might need 10 to 12 feet of 3/16" ID tubing to slow the flow down enough for a perfect pour.
The Theory & Practice of Force Carbonation
Understanding the Tool
A force carbonation chart is fundamentally a lookup table that coordinates three physical variables: PSI (Pressure), Temperature, and Volumes of CO₂. Bars of CO₂ dissolve into beer according to the interaction of these forces.
At equilibrium - the point where the gas entering the beer equals the gas leaving it - a specific pressure and temperature combination will yield a predictable, repeatable carbonation level.
Standard charts are set up so you choose your beer’s temperature as it sits in the keg (the Y or vertical axis) and a pressure to set on your CO₂ regulator (the X or horizontal axis).
The intersecting value tells you how many volumes of CO₂ the beer will hold. In practical terms, this highlights a critical relationship: cold beer dissolves CO₂ more readily, requiring lower pressures, while warm beer resists carbonation, requiring higher pressures to achieve the same result.
The Physics of Fizz (Henry's Law)
Beer carbonation is expressed in "volumes," which refers to the volume of gas dissolved into the same volume of liquid. The force carbonation chart is a graphical solution to Henry's Law, which states that at a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.
Every beer style has a target range - British ales sit low at 1.5–2.2 volumes, while American lagers push higher to 2.2–2.7 volumes. The chart is your roadmap to hitting these targets precisely.
The Workflow
Professional brewers follow a strict protocol to ensure consistency. First, they decide the target based on the beer style. Next, they chill the beer to serving temperature, knowing that cold liquids are more receptive to gas.
Once chilled, they set the regulator to the corresponding PSI found on the chart.
The beer stays connected to the gas until it reaches equilibrium, a process that takes 10 to 14 days in the "set-and-forget" method. While faster methods exist - such as using carbonation stones to create millions of tiny bubbles or shaking the keg under high pressure - these can often lead to over-carbonation if not carefully monitored. The chart is most accurate when time is allowed to do the work.
Advantages & Limitations
The primary advantage of using a chart is predictability. It removes the guesswork, allowing you to hit specific carbonation levels for specific styles, which is crucial for balancing draft systems.
The "set-and-forget" simplicity is also a major pro for busy brewers. However, the limitation is time. Waiting two weeks for carbonation requires patience.
Furthermore, the chart assumes your temperature readings are accurate; if your keg is 5°F warmer than you think, your PSI setting will be wrong, and your beer will be flat.
Master Tips for Consistency
- Cold-Crash First: Chill your beer close to serving temp before turning on the gas. This creates a stable baseline for the chart.
- Record Everything: Keep a log of Pressure, Temp, and Time for every batch. This allows you to refine your process.
- Measure, Don't Guess: Use a calibrated thermometer inside your kegerator, ideally submerged in a glass of water, to get the true liquid temperature.
Conclusion
A force carbonation chart translates the physical relationship between pressure, temperature, and CO₂ solubility into a practical tool.
It is accurate for equilibrium, easy to use, and supports style-specific targets.
However, it does not replace the understanding that CO₂ takes time to dissolve. By cross-referencing this chart with patience and accurate temperature control, you will achieve the perfect pour, every time.
Looking for a faster way?
Be sure to also check out our Keg Carbonation Calculator for precise math.
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