The CO2 tank is one of the most critical parts of a kegerator, given the core role it plays in the pour experience and taste. There is no way you are deriving maximal value from your kegerator if your CO2 tank is not adequately optimized or installed. But before we answer the hordes of questions in your mind about kegerators and CO2 tanks, what essentially is a CO2 tank?

The CO2 tank houses the carbon dioxide, which primarily propels the beer into your glass from the keg. The CO2 is a pressurized tank with such pressure pushing the beer via the keg coupler. The dispensed beer is vertically transported through the faucet tap. In the least technical summary, the gas from the CO2 tank enters the keg, and the beer deliciously arrives in your glass. Voila!

We have explained how CO2 tanks work. Next, let us answer some of the most pressing questions you have about these tanks. 

1. What sizes are CO2 tanks?

Given the versatility of beer enthusiasts’ homebrewing needs, CO2 tanks come in a wide range of sizes in today’s market. This cuts across very portable CO2 tanks, medium-size and really gigantic ones that virtually can’t be manually lifted.

An investigation of what is obtainable in the market reveals that today’s most prevalent CO2 tank sizes include the 2½-pound cylinder, 5-pound cylinder, 10-pound cylinder, 15-pound cylinder, and the 20-pound cylinder.

The 2½-pound cylinder, which is the smallest we saw, comes at dimensions of 3½’’W x 18¼’’H. The 20-pound cylinder, which is the biggest, comes at dimensions of 8’’W x 27½’’H.

2. How can you determine the set CO2 tank pressure?

The draft beer regulator shows you the pressure your CO2 tank is set at in PSI (pounds per square inch). The regulator links the air hose and the tank.

There are commonly two types of regulators. These are the single gauge and the double gauge regulators. 

Single gauge regulators solely read the prevalent CO2 tank pressure. If you have a dual gauge regulator (same as the double gauge), the gauge reading the regulated pressure typically ranges from 0-60 PSI. This gauge can be adjusted by hand.

Examine the arrow this gauge is pointing to. The number it points to indicates the amount of pressure that keg receives from the CO2 tank or the beer’s pouring pressure.

3. Is there an ideal pressure my tank should be set at?

This is quite flexible as people have different pressures they prefer their beer being poured at. 

That said, American breweries conventionally recommend that your CO2 pressure shouldn’t be lower than 12 PSI and shouldn’t be higher than 14 PSI. 

This is, however, not definitive given the variety in kegerator designs. To be on a safer side, specifically, ask the distributor you got your keg from (or the brewery as the case may be) what pressure should be delivered from the tank to your keg.

Setting your CO2 pressure correctly is important because there could be under-carbonation in your beer if it is too low. In such scenarios, the beer tastes a bit too flat. 

On the other hand, if the pressure is too high, it can result in over carbonation. This is demonstrated in the beer being too foamy.

4. How can you ascertain the amount of remaining CO2 in your tank?

If you want to determine the volume of CO2 left in your tank, you will need a double gauge regulator instead of its single gauge counterpart. 

Remember, as we previously established, the single gauge draft beer regulator can only read the regulated pressure. The double gauge can read both the regulated pressure and the high pressure.

The high pressure here reflects the remaining CO2 quantity in the cylinder. This high-pressure gauge has a pressure range of 0-3,000PSI. 

5. What duration can a CO2 cartridge last for a keg serving?

The duration a CO2 cartridge lasts is one common question we get all the time. A lot of the period a cartridge lasts relies on the keg size.

Let us assume you have 7.75 gallons of draft beer (the same quantity derivable from a quarter barrel). Dispensing it would require at least ½ CO2 pounds.

Now, considering that most homebrewers we have come across prefer the Corny kegs (with a standard capacity of 5 gallons), you can expect at least a keg size of 44kg to dispense such CO2 tank size.

Let us move the conversation to portable cartridges. Considering the duration a CO2 cartridge can hold relating to the keg, you can expect a single 16-gram CO2 cartridge to handle 1/3 of a 5-gallon keg. 

If you have a bigger cartridge, say one running into 68grams, it could last you as many as four kegs. 

This is particularly when the ambient temperature is cooler. If it is hot, you could get around two kegs.

6. Where can you refill a CO2 tank?

Traditionally, your CO2 tank can be refilled at any store around you where fire extinguishers are sold. 

Alternatively, a welding supply shop around your neighborhood should be able to refill your aluminum gas tank. 

If these two options can’t refill your tank, you will have to look for the nearest dedicated draft beer shop around you.

7. Should the CO2 tank be kept inside or outside your kegerator?

Admittedly, this question divides opinion. Some homebrewers believe where you place your CO2 tank (inside or outside your kegerator) is inconsequential. 

We have also come across the school of thought who says keeping your CO2 tank in the fridge reduces the pressure. 

With these divergent opinions established, most CO2 tanks are kept outside to maximize the kegerator’s refrigeration compartment space. This is typical when you need larger space to store more kegs or bigger kegs.

We have seen that the dispensing experience may not be critically affected by the distance between your keg and the tank, provided your air hose is good enough. 

Make sure your tank sits uprightly. Certainly, you need the tank reasonably spaced from any heat source.

8. How can you determine if your tank is leaking?

CO2 leaks from your tank can be hazardous, especially if you have flammable things around. While not all CO2 leaks can be readily detected from the conventional hissing sound (of escaping gas), there are other ways you can identify and promptly remedy gas leaks.

One way is checking your PSI level in the morning and measuring it against where it was the previous night. If you notice a dramatic drop in the level, chances are CO2 is leaking.

You can ascertain this from the soapy water test. This is essentially testing the tank with a solution of dish soap and water concentrate. Just a few drops of the soap would do.

Before you get into the testing proper, it is advised to disconnect your beer keg. Consequently, set the pressure to zero all the time, ensuring the tank is in the ON position.

Now bring your soapy water on and spray it across your kegerator, keenly checking out for bubbles. If you notice bubbles, it is either because your kegerator connection is not secure or your tank is leaking. 

If you don’t want that spray approach, you can disassemble the system and dip each part in the solution. If any starts rapidly bubbling, there you have your culprit!

9. How can you determine if a CO2 tank has expired?

What many homebrewers appear unaware of is that CO2 tanks expire. You can determine the expiry date of a CO2 tank from the information usually displayed on the tank’s top.

First, check for the tank’s manufacture date. It is conventionally stipulated in the third row in a month/year (mm/yy) format. Some manufacturers state theirs as the “Born On” date.

From this date, The US Department of Transportation mandates that your CO2 tank be certified every five years and affirmed with their official markings.

This means your CO2 tank must be periodically hydro-tested in five-year intervals after the tank’s manufacture date.

Resources

Home Brewing Keg Tips

Kegerator Basics – What You Need To Know About CO2

6 Common CO2 Questions Answered

All You Need to Know About CO2 Tanks for Beer Carbonation

8 Answers to Frequently Asked Draft Beer CO2 Questions

CO2: The Gas Source For Dispensing Keg Beer

How Kegerators Work