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Is Degassing Mead Necessary? Is it Really Important!

Is degassing mead necessary?

Mead is one of the oldest alcoholic beverages known, and is thought by many to actually be the first. There are references in Ancient Greek texts to a honey-based beverage drunk to honour Aphrodite, the goddess of love, and the Vikings were huge fans of a horn of mead post-battle.

It’s even been posited that ancient African tribes would drink a sort of naturally occurring mead that collected where bees had left honey in hollowed-out tree trunks. 

Naturally, then, you’d think it’d be pretty easy to make your own mead. But much like any home-brewing there are a few wrinkles to consider, and there is more than one step that can make or break a good batch of mead. 

One of the most contentious of these steps is whether or not degassing – i.e. removing the built-up carbon dioxide – is necessary. Some people claim that it’s an absolute necessary, as the fermentation process may be negatively affected by the build-up of carbon dioxide (which is, after all, a waste product of fermentation).

Others insist that degassing is completely unnecessary and that the CO2 levels have nothing to do with the quality of mead. With so many differing opinions out there, it can be pretty bewildering figuring out the best option. 

What does Degassing Mead involve? 

In order to figure out if degassing mead is necessary, it’s probably a good idea that we’re clear on what, exactly, we mean by “degassing”.

Degassing is the process of removing carbon dioxide (CO2) from your mead, but it does not refer to any one method of removing said gas. It could be as simple as stirring the mixture, or as complex as using a vacuum pump to thoroughly remove the CO2. Which method you use (or if you use any degassing method at all) is entirely up to you, but we will be focussing on the former throughout this article. 

Does Degassing stop fermentation

Does Degassing stop fermentation?

Simply put: no. COis a waste product of the fermentation process, as mentioned, and removing it will not prevent the yeast in your must (the unfermented honey-water mix prior to fermentation) from continuing to prevent, nor will it cause oxidisation in your primary fermentation. 

It can in fact be argued that degassing mead is beneficial to the primary fermentation process; because mead must is very thick and viscous, it can be difficult for COto escape the mixture during primary, which can inhibit yeast activity. Simply giving the must a stir gets rid of the CO2 and, therefore, leaves the yeast to get on with fermentation. 

Which leads us to our next question: 

Should I stir my Mead while fermenting? 

Whilst this is a contentious topic within the brewing community, the consensus leans overall to frequent stirring during primary fermentation. When initially fermenting, yeast is aerobic, which means that it requires oxygen to do its thing and expels carbon dioxide as a waste gas.

Stirring the must at this point achieves two things: it releases the waste CO2 and it reintroduces oxygen to the mix. Both of these are beneficial to your yeast and will keep fermentation ticking over. 

For best results, you should stir 2-3 times a day. Stir slowly at first, lest you cause the mixture to foam up too much and overflow, then gradually stir more quickly (but not too quickly!). Your mead will generally stop foaming within 60-90 seconds, at which point you can stop. Be sure to use a sanitised, stainless-steel stirrer in order to avoid introducing contaminants into the mixture. 

as mead

What are the best ways to degas mead? 

We’ve already touched on stirring your mead 2-3 times a day, but are there any other ways to degas it? There certainly are: 

Give it a gentle shake 

The most sure-fire way to avoid introducing contaminants, a gentle (gentle!) shake/swirl of your carboy (or whatever container you’re using) can free the built-up CO2 and introduce a bit of oxygen into the mix. We must emphasise doing this gently – if you get carried away you’re going to end up cleaning the aftermath of a meadsplosion off your garage walls. 

Use an agitator rod 

An agitator rod is an attachment for a power drill with foldable blades – perfect for a more thorough degassing of your mead, but one that can easily cross the line from degassing to aeration if you’re overzealous! Use sparingly or, if you’re not confident with using this method, not at all. 

Use a vacuum pump

Whether using as simple as a wine saver or an automated vacuum pump, this is probably the most efficient way of degassing your mead, since it completely eliminates the chance of introducing oxygen into the mix.

That said, you want some oxygen in the mix in primary fermentation, so if you’re going to use a vacuum pump you’re probably best doing it during or at the end of secondary fermentation. 

five carboys of fermenting meads


‘Racking’ refers to the process of transferring your mead (or wine/beer/etc.) to another container. Typically done at the conclusion of primary fermentation, racking helps to eliminate the sediment from your mixture and provides a fresh environment for the remaining fermentation process in secondary. 

It also eliminates a lot of built-up CO2, which leads many to conclude that active degassing is not actually necessary. The racking process takes care of it. 

How do you know when degassing is done? 

Typically, there’s no need to degas after primary fermentation, which will take about four weeks. When primary fermentation is finished – which is to say, when there’s a deep layer of sediment at the bottom of your mead – it’s time to rack it (transfer it to another container) and leave it to the secondary fermentation process. 

The very act of racking your mead helps with getting rid of excess CO2, so it’s not really necessary to degas during secondary. That said, some people prefer to use a vacuum pump to siphon off any excess CO2 before bottling; whilst it’s debatable if this helps, it certainly does not run the risk of aerating (oxidising) your mead. 

What does run this risk is simply stirring the mead at this point. This is to be avoided in secondary fermentation, as not only will it oxidise the mixture, it may reintroduce dead yeast and sediment (“lees”) to the mix. 

So: do I actually need to degas mead or not? 

As mentioned, it’s a topic of no small contention within the mead-brewing community, and there’s no real consensus. That said: degassing your mead doesn’t hurt as long as you avoid going too far and end up accidentally aerating the mixture.

It’s important to therefore do it properly: general degassing should only be done during primary fermentation, vacuum degassing in secondary fermentation, and overly vigorous degassing not at all.

Much like home-brewing overall it’s not an exact science, and things may go wrong even if it seems like you did everything right. 

Happy fermenting! 

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Lisa Hayden-Matthews

Lisa Hayden-Matthews

A bike rider, triathlon enthusiast, amateurish beach volleyball player and nature lover who has never lost a dare! I manage the overall Editorial section for the magazine here and occasionally chip in with my own nature photographs, when required.

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