Brewer's Ed

Bottle and Keg Conditioning: The Basics of When and Why

The first in a short series about package-finished beer

By Nik Allen

Aug 10, 2022


Carbonation is essential to the flavor profile of any beer. Without bubbles, most beer recipes fall flat (editor’s note: pun definitely intended). This article will take you through a few methods of carbonating your beer in both bottles and kegs, starting with a quick overview of how we talk about and measure carbonation in beer. 

Why Bottle Condition?

For homebrewers, bottle conditioning tends to be the simplest and most accessible way to finish your beer, with a smaller footprint and upfront cost than kegging. Both new and used kegging equipment is widely available, but can be a pricey way to start. I’ll refrain from comparing complexity and labor, since I’ve seen brewers argue well for the ease of either practice.

For commercial brewers, bottle conditioning is a matter of preference and patience. Force carbonating in brite tanks can be more consistent than package conditioning, depending on how you are performing this task. Dosing priming media in a brite tank or mixing tank can potentially result in inconsistent blending if done incorrectly. In-line dosing is an industry standard that can be reliable but comes with additional capital and maintenance costs, not to mention warehouse footprint. While a homebrewer might be able to squirrel away batch after batch in their closet or basement, it’s a greater feat to dedicate temperature-regulated storage to bottle conditioning. That’s not to say this is a niche endeavor — some breweries rely on bottle conditioning to give their beer the ideal character they desire.

Bottle-conditioning can serve to stabilize packaged beer from certain forms of staling. Packaging inevitably introduces oxygen through atmospheric exposure and agitation, and beverage-grade carbon dioxide is not pure. A healthy re-fermentation through bottle conditioning can scrub oxygen before it can degrade the quality of the beer. Bottle conditioning can also assure higher levels of carbonation that may be difficult to maintain throughout traditional packaging methods. As temperatures fluctuate during storage, the ability to maintain a level of higher dissolved CO2 is also challenging. By re-fermenting and carbonating in a closed system, higher CO2 levels are attainable.

Volumes of CO2

Many people might consider a beverage to be either carbonated or not carbonated, without a lot of nuance. When brewers talk about carbonation, the qualitative terms most used are flat,” medium,” and spritzy.” However, quantitatively we can be much more specific. In the US, the standard unit to measure beer carbonation is volumes of CO2,” which equates to the physical space that an amount of carbon dioxide would take up at 32°F (0°C) and 1 atmosphere of pressure (~15 PSI). It’s easiest to conceptualize it as the amount of bubbles in a pint: the higher the number of volumes, the more bubbles in your beer.

2 5pints

Concept: a pint of beer with 2.5 volumes of CO2 would mean that if you removed the CO2 from the beer, it would physically take up the space of 2.5 pint glasses. 

Beers typically range in carbonation from 1 – 4.5 volumes of CO2. Saisons and hefeweizens demand a refreshing spritz while an aged barleywine will often be quite petillant (sparkling). It’s easy to think of cask beer or traditional lambic as having no carbonation, but these beers do still have bubbles, albeit very few. This is often the result of lingering CO2 from the initial fermentation and not necessarily secondary conditioning.

Common beers by volumes of CO2

StyleVolumes of CO2
Cask beer0.5–1.5
High-alcohol/barrel-aged beers1.0–2.5
Most American beer styles2.2–2.8
German hefeweizens3.0–4.0
Most Belgian beer styles3.0–4.5

What's Next?

This was just a short overview of conditioning and carbonation. In future installments we’ll discuss priming media, other ways to condition beer, and when to add yeast for a secondary fermentation. Stay tuned for more, and let us know what your carbonation and conditioning questions are. 

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