What Temperature Should a Kegerator Be?

The number

38 F, and why it is the compromise

If you serve several styles from one cabinet, 38 F is the setting. It is not the perfect temperature for any single style; it is the temperature at which the largest number of styles pour well and taste close to right, which is a different and more useful thing.

Colder than about 34 F and you risk freezing beer in the lines or in the keg nearest the cold plate, and cold also suppresses aroma -- a 32 F IPA smells of nothing. Warmer than about 45 F and CO2 comes out of solution readily on the way to the glass, which is foam, and the required serving pressure climbs to hold the same carbonation.

Thirty-eight Fahrenheit sits in the middle: cold enough that CO2 stays dissolved at a modest serving pressure, warm enough that hop and malt aroma survive. If you only ever drink stout, run warmer. If you only drink pilsner, run colder. For a mixed kegerator, 38 F.

The pairing

Temperature and pressure are one setting, not two

This is the thing that catches out almost every new kegger. How much CO2 stays dissolved in beer depends on both the pressure above it and the temperature of the beer, and the two move together. The same 12 psi that holds 2.5 volumes of CO2 at 38 F holds considerably less at 50 F, because warm beer cannot retain as much gas.

So when you change the temperature, you change the carbonation level unless you change the pressure to match. A kegerator turned down for summer will slowly over-carbonate the beer in it at an unchanged pressure; turned up, it will go flat. Neither is a fault in the beer.

The practical rule: set the temperature first and leave it alone, then set the pressure from a carbonation chart for that temperature and the volumes your style wants. The mechanics of getting there are in CO2 regulator settings, and the method for carbonating from flat is in how to force carbonate.

The real problem

Your first pour is foam because the tower is warm

Here is the symptom almost everyone describes: the first pint of the evening is three quarters foam, you dump it, and the second pint is perfect. The thermostat is not the problem. The tap tower is.

A tap tower sits above the cabinet, in room-temperature air, with several inches of beer line and a brass faucet inside it. Between sessions that beer warms to something close to room temperature. Warm beer cannot hold its CO2, so it breaks out of solution inside the line and arrives at the faucet as foam. Once a pint of cold beer has flushed the tower, everything behaves.

• A tower cooling fan is the proper fix. A small fan in the cabinet pushing cold air up into the tower keeps the line and the faucet at cabinet temperature. Most kegerators have a duct for this, and it is the single highest-value kegerator upgrade there is.
• Insulating the tower helps a little. It slows the warming but does not prevent it, because there is no cold source in the tower to maintain.
• A keezer with faucets through a collar avoids it entirely, because the line stays inside the cold space right up to the shank. That is one of the quiet advantages covered in kegerator vs keezer.

Measuring it

The cabinet thermostat is not the beer temperature

A kegerator thermostat reads air, usually near the cold plate or the evaporator, which is the coldest part of the cabinet. The beer in a keg at the far end of the cabinet can be several degrees warmer, and the beer in the tower warmer still.

If carbonation is behaving strangely, measure the beer rather than trusting the dial. The simple method is a glass of water left in the cabinet overnight with a thermometer in it -- water has similar thermal behavior to beer and it tells you what a keg is actually sitting at. A dual-stage controller with the probe taped to a keg does the same job permanently and is the correct answer for a converted fridge or a keezer.

Edge cases

Styles that want something else

Stout and porter. Traditionally served warmer, 45 to 50 F, and at lower carbonation. In a mixed cabinet at 38 F a stout will taste tight and cold; pour it and let it sit for five minutes rather than running the whole cabinet warm.

Hefeweizen and Belgian styles. These want far more CO2 -- up to 3.5 volumes -- which at 38 F means pressures in the high teens or low twenties. That is a legitimate setting, but it needs longer beer line to pour without foaming, and it will over-carbonate anything else on the same regulator body. This is the case for a secondary regulator manifold, covered in best CO2 regulators.

Nitro. A nitro stout runs on a beer gas blend at 25 to 35 psi through a restrictor plate faucet, and the pressure is doing a different job entirely. Do not set a CO2-only kegerator to nitro pressures.

Where this came from

The basis for this

Kegerator temperature ranges and keg capacities are the manufacturers' published specifications. The temperature, CO2 volume and pressure pairings follow standard draft-dispense carbonation tables and long-standing homebrew practice; the figures in the table are working ranges rather than measurements from our own cabinet. See how we pick.