On this blog, we’ve answered multiple questions about carbonation already. Today, we’re going to look at a question that occupies the minds of many beer drinkers and new homebrewers. Let’s start with a quick answer:

Beer is carbonated because the creation of carbonation is a natural part of the brewing process. When yeast turns the sugars in the wort into alcohol, it also creates CO2 which is responsible for the carbonation. However, carbonation is also added artificially by many brewers because it gives the beer more flavor and a more interesting mouthfeel.

However, that certainly doesn’t answer the question entirely. Below, we’ll first look at if beer needs to be carbonated at all and why brewers add carbonation. We’ll explain the different ways to add carbonation to a beer and the advantages and disadvantages for consumers and homebrewers for each method. Read on!

Does Beer Have To Be Carbonated?

Beer absolutely doesn’t have to be carbonated to become beer (we’ll explain that in a moment). However, beer is carbonated because consumers generally enjoy it the most. Drinking a beer without carbonation means you’ll be drinking a beer without any form of foam.

Furthermore, it will also taste very flat because the bubbles aren’t there to create an enjoyable mouthfeel. Finally, carbonation also allows the flavors of the beer to come forward, and without it, you would just be drinking slightly bitter alcohol-water.

What Types Of Carbonation Are There?

First of all, it’s good to know that there are two different carbonation forms: natural and forced. Each of these types happens in different ways, at different brewers, and in different circumstances. Let us explain why each method is used.

Natural Carbonation

Natural carbonation, as the name suggests, is carbonation that happens naturally within the beer when the beer is brewed. Before beer has any form of alcohol or carbonation, it’s just sugary water we call ‘wort’. In the case of regular lagers such as Budweiser and Heineken, Wort consists of water, barley, hops, and sometimes rice or corn.

Both the barley, corn, and rice contain natural sugars. However, these sugars don’t turn into alcohol themselves. For this to happen, we need to add yeast. Yeast is a microorganism that turns the sugar in the barley, corn, and rice into alcohol.

When this process takes place, the yeast produces a by-product called CO2. When the tank in which the beer is brewed is closed, the CO2 has no way to escape into the atmosphere. This means it turns into a liquid form of CO2 called carbonic acid. This carbonic acid is what we refer to as carbonation, and, in its most natural form, it’s an entirely normal part of the beer-making process.

Forced Carbonation

In some cases, and depending on the type of beer that you’re brewing, natural carbonation is not a possibility. Therefore, homebrewers and industrial brewers rely on the process of forced carbonation to achieve carbonation when it’s not possible otherwise.

Forced carbonation is done by directly infusing CO2 into the beer by using a gas cylinder and a keg that’s made for CO2 carbonation (typically, a corny keg is perfect for this) and a tank of carbon dioxide with a regulator.

Then, there are two types of ways to force carbonate beer. The first method connects everything and then adjusts the regulator to 20 PSI. After this, you let it sit for 7 – 10 days, and you’ll have a perfectly carbonated beer.

The other method involves more effort but is faster. It consists in turning the regulator up to 30 PSI and shaking the keg for the first 20 – 30 minutes. After this, you dial down the regulator to 20 PSI and let it sit for another 2 – 3 days.

Furthermore, it’s essential to know that the PSI levels also depend on the temperature at which the beer is carbonated. The PSIs mentioned above are general guidelines, but colder beers will carbonate much more quickly than carbonated beer at higher temperatures.

What Type Of Carbonation Is Best And Are There Differences?

This may have you wondering what type of carbonation is best and if there are distinct advantages or disadvantages for consumers and homebrewers.

Natural Carbonation

Natural carbonation is claimed by many to create better results. For example, it’s supposed to make a thicker foam head with more delicate bubbles. Also, it creates more lacing (the rings left on the glass after the foam head dissipates, which is a good thing). Furthermore, it requires less equipment than forced carbonation, and it is the natural way to brew beer making it more traditional.

One of the disadvantages is that it takes a very long time compared to forced carbonation. Natural carbonation needs 2 – 4 weeks to develop fully. Furthermore, there’s room for error. If too much sugar is added, the beer can become over-carbonated, or the bottle can explode because of the pressure. Finally, the yeast will settle at the bottom of the bottle, which doesn’t look appealing.

Natural carbonation best fits brewers with ample time and creates a traditional product with a thicker foam head.

Forced Carbonation

On the other hand, forced carbonation is a much quicker process and can be done in 3 – 10 days, depending on the method used. Furthermore, it’s easier to make since you set the CO2 regulator to a specific setting that is calculated quickly. This is different than natural carbonation since adding the right amount of sugar requires some guesswork.

Finally, forced carbonation creates a more transparent product that doesn’t have leftover yeast lying around on the bottom of the keg or bottle.

However, there are also drawbacks. Forced carbonation requires you to buy expensive equipment; this is the biggest negative of this method. Furthermore, the foam head of the beer will be less prominent and most likely dissipate faster. Finally, forced carbonation is not a traditional method.

When Does Fermentation Take Place?

As explained, fermentation (for both natural and forced processes) starts when yeast is added to the wort. However, this is not the fermentation that you’ll end up tasting in your beer. This is because the first round of fermentation is ‘let go off’ by the brewers.

This is because the first round of fermentation only happens. After all, brewers want to turn the sugars in the barley, corn, and rice into alcohol. The CO2 generated during this first round escapes the tanks it’s brewed in.

The carbonation that you end up tasting in your beer happens after the sugars have turned into alcohol. This is when brewers either add extra sugar and a small amount of yeast in the tanks or in the bottles in which the beer is eventually sold, or they force carbonate it.

When brewers decide to let this second fermentation happen naturally, they either seal the tanks in which the beer is brewed or pour it into kegs or bottles and let these sit for 2 – 4 weeks before selling. If they decide to bottle it already, then you’ll end up with a bit of leftover yeast on the bottom of your bottle.

Do Different Types Of Beer Have Different Carbonation Levels?

Different types of beers certainly have different levels of carbonation. This is measured by the volume of CO2 (one volume of CO2 is equivalent to two grams of CO2 per liter). Homebrewers and commercial brewers typically aim for the volumes that are displayed below.

For example, we see that European lagers (such as Heineken and Stella Artois) have a slightly lower amount of carbonation compared to American lagers such as Budweiser. This is normal because European lagers tend to be more bitter, and there’s less carbonation required to give the beer an exciting taste and mouthfeel.

On the other hand, British ales have long struggled in the United States because they were deemed warm and flat. When we look at the amount of carbonation, we can see that there’s indeed a lot less carbonation in these types of beers compared to American lagers, and it explains the consumer sentiment.

StyleVolume of CO2
American ales2.2–3.0
British ales1.5–2.2
German weizens2.8–5.1
Belgian ales2.0–4.5
European lagers2.4–2.6
American lagers2.5–2.8