Switching to kegs

Kegerator or keezer, corny kegs, CO2 safety, the carbonation chart and a line-cleaning routine for brewers done with bottling day.

Steel beer kegs with tags on a cellar floor
Photo: Mtaylor848, CC BY-SA 4.0, via Wikimedia Commons

What switching to kegs involves

Switching to kegs replaces 50 bottles with one 5 gal (19 L) corny keg. You need a cold space, a keg, a CO2 cylinder, a regulator, lines and a faucet. A homebrew kegerator bundles the fridge and tap; a conversion kit turns a fridge you own into one; a keezer puts kegs in a chest freezer run by a temperature controller.

  1. Clean and sanitize the keg

    Disassemble posts and dip tube now and then, clean, then sanitize per the label.

  2. Fill and purge

    Rack cold beer in gently, seal the lid and purge the headspace with a few bursts of CO2.

  3. Set the regulator

    Pick a pressure from the chart for your beer temperature and target volumes.

  4. Wait, then pour

    Set-and-forget carbonation takes about one to two weeks. Check for leaks with soapy water.

CO2 cylinders and pressureKeep cylinders upright and secured, and always use a CO2-rated regulator (US CO2 tanks use the CGA 320 valve fitting); never connect a cylinder straight to a keg. Store tanks cool and away from heat. CO2 displaces oxygen and collects low: ventilate, close the tank valve and leave the room if a tank leaks. Never exceed a fermenter’s or keg’s rated pressure.Source: Kegco: Everything you need to know about CO2; OSHA hazard bulletin on CO2

Fermenters & temp control

All 14 in fermenters & temp control

Hydrometers & meters

All 1 in hydrometers & meters

Brewing chemicals & water

All 4 in brewing chemicals & water

Cleaning & sanitizing

All 18 in cleaning & sanitizing

Keg carbonation chart

BYO's figures put 2.4 volumes at 40°F (4°C) at about 11.2 psi; add about 0.5 psi per 1,000 ft of altitude.

Keg pressure (psi, sea level) by beer temperature and target CO2 volumes

Beer temp1.8 vol2.0 vol2.2 vol2.4 vol2.6 vol2.8 vol3.0 vol3.2 vol
32°F 0°C1.63.55.47.39.211.012.914.8
34°F 1.1°C2.34.36.38.210.212.114.116.0
36°F 2.2°C3.15.17.29.211.213.315.317.3
38°F 3.3°C3.96.08.110.212.314.416.518.6
40°F 4.4°C4.76.89.011.213.415.517.719.8
42°F 5.6°C5.57.710.012.214.416.718.921.1
44°F 6.7°C6.38.610.913.215.517.820.122.4
46°F 7.8°C7.19.511.814.216.619.021.323.7
48°F 8.9°C7.910.412.815.317.720.122.625.0
50°F 10°C8.711.313.816.318.821.323.826.3
52°F 11.1°C9.612.214.817.319.922.525.127.6
54°F 12.2°C10.413.115.718.421.123.726.329.0
56°F 13.3°C11.314.016.719.522.224.927.630.3

Formula: PSI = −16.6999 − 0.0101059·T + 0.00116512·T² + 0.173354·T·V + 4.24267·V − 0.0684226·V². Checked against the BYO grid (40°F and 2.4 vol: 11.19 psi by formula, 11.2 psi on the chart). Regulator gauges read relative to local air pressure. BYO notes that Denver needs about 3 psi over the sea-level chart; add roughly 0.5 psi per 1,000 ft. Sources: BYO: Carbonation priming chart; Brewer's Friend: Force carbonation chart; Brewers Association: Draught Beer Quality Manual.

Keg carbonation chart and PSI calculatorDial in your temperature and CO2 volumes for the regulator setting.

CO2 safety and line cleaning

Keep the cylinder upright and secured, always use a regulator, and never exceed a keg's or fermenter's rated pressure. In a small room or basement, a CO2 monitor gives early warning of a leak. Clean beer lines regularly with a hand-pump kit and a line cleaner used per its label.

Chemicals: label directions onlyUse sanitizers, cleaners, acids and salts only at the dilution and contact time on the label. Wear eye protection with acids and powders, add acid to water, keep them away from children and food prep. Star San is EPA-registered (Reg. No. 65001-1) as a no-rinse sanitizer at label dilution.Source: EPA Star San label

Kegging mistakes to avoid

  • Kegging warm beer and expecting it to carbonate on schedule: chill first.
  • Forgetting to purge oxygen from the headspace.
  • Storing the CO2 cylinder loose: secure it upright.
  • Pouring through dirty lines: set a cleaning routine from day one.

Keep a few bottles for sharing? A counter-pressure filler or beer gun lets you bottle from the keg.

Related reading: best kegerators for homebrew, best homebrew keg systems and best CO2 regulators for kegging.

Switching to kegs: questions

Is kegging worth it for homebrew?
If bottling day is the part you dread, yes: one keg replaces about 50 bottles and carbonation is adjustable. It costs more up front and needs a cold space.
Kegerator or keezer?
A homebrew kegerator is plug-and-pour for two or three kegs. A keezer (chest freezer plus controller) holds more kegs but needs a collar or taps you install.
What PSI do I set to carbonate a keg?
About 10–12 psi at 38–40°F (3–4°C) for roughly 2.4–2.5 volumes (2.4 vol: 10.2 psi at 38°F, 11.2 psi at 40°F), per BYO's chart. Use the keg carbonation chart for other temperatures.
How big a CO2 tank do I need?
A 5 lb cylinder is the common homebrew size and fits inside most kegerators. Cylinders often ship empty; get them filled or exchanged at a gas supplier.
Is CO2 dangerous at home?
CO2 displaces oxygen, so a large leak in a closed room is dangerous. Secure the cylinder upright, check fittings with soapy water, ventilate and leave if you suspect a leak.