How To Degas Wine

One of the byproducts of fermentation that we do not want in the finished wine or still mead is carbon dioxide.

Even sparkling wines first need to be degassed and this part of the process can sometimes be tricky because, after all, we cannot see carbon dioxide in the wine and have to rely on tasted samples alone.

Carbon dioxide will affect multiple things in wine or mead; clarity, flavour and mouthfeel included so it is important to make sure we get rid of any residual carbon dioxide left in solution after fermentation. Degassing the wine is the answer.

How do we go about degassing a wine or mead then?

There are a few tried and tested methods which are fortunately quite simple to do although some do take a little take time.

The Importance Of Degassing Wine

Yeast creates carbon dioxide during fermentation and although when you sample a fermented wine it may not seem fizzy there is still residual carbon dioxide in solution.

Temperature and time both affect how much residual carbon dioxide is in the wine or mead but we want to remove all of it before we finish the wine either by stabilising or bottling it.

Carbon dioxide left in the wine will have some of these effects in the end product:

Poor Clarity

You will find it difficult to achieve crystal clear wines or meads whilst there is carbon dioxide in solution.

The agitation caused will prevent yeast, proteins and other particles in solution from flocculating and settling to the bottom of the fermentation vessel.

Too Acidic

Carbon dioxide in solution creates carbonic acid. In some drinks this is fine, sparkling wines and fizzy beverages are going to have a more acidic palate because of the balance of sweetness and flavour aren’t going to be overwhelmed by the carbonic acid bite.

The majority of wines have an acidity that is right for the profile. Having too much carbon dioxide in solution could interfere with this.

Ways To Degas Wine

There are three main ways to remove carbon dioxide from wine. They range from being extremely simple and requiring no equipment to more complex and needing specialist equipment.

The main ways to degas wine or mead are:

• Time
• Agitation
• Under vacuum

Degas Wine By Giving It Time

By far the simplest method to Degas a wine or mead is to simply leave it long enough for the CO2 to disperse naturally.

This is the most common industry practice as nearly all wine sold commercially is aged at least for a year or two.

It will not take years for all the CO2 to disperse and ageing for 3 – 4 months is usually enough.

If you are ageing the wine I would recommend slightly longer than this and to be sure the wine does not sit on any sediment for too long as this will impart off flavours.

Agitation To Degas Wine

Agitation is the most common method of degassing wine for those who don’t want to wait for months for it to degas naturally.

The process is simply to stir or swirl the wine vigorously enough so the carbon dioxide fizzes out. This could be done with a brewing paddle or spoon.

There is also a number of devices available on the market to aid this. Degassing wands that attach to a drill make the job very easy.

How Much Stirring?

To properly Degas a wine or mead by agitation it can take a lot of stirring up to a few minutes at a time over the course of a week is a rough guide to the amount of agitation needed.

Creating A Vacuum To Degas The Wine

Creating a vacuum in the vessel where the wine is being stored creates negative pressure in the headspace.

The negative pressure caused by a vacuum will force the carbon dioxide out of solution and it will rise to the top of the wine.

There are not many commercial examples on a homebrew scale for degassing wine via a vacuum.

There are wine savers that attach to bottle openings that are designed to keep wine stored after opening that work via a vacuum. The problem with these is they are made to be attached to single bottles attaching them to a carboy or other vessel will need various modifications

To degas wine by creating a vacuum still takes a while, as in, a number of hours under constant vacuum.

The vacuum cannot be too strong or it will possibly damage the carboy and the vacuum needs to be kept constant so this method is really only suitable for those who make lots of wine and are needing to transfer it with some urgency.

How Do You Know When A Wine Is Degassed?

When you are degassing a wine by agitation you will notice the carbon dioxide being released and creating foam on the surface of the wine.

Agitating the wine like this is a good way to check how much CO2 is left in solution.

When the foaming during agitation starts to subside this is a good indication you have degassed the wine. I like to use the following method:

1. Take a sample of the wine in a hydrometer test jar.
2. Cover the opening with your palm and give the sample a good shake.
3. Check for visible foaming and carefully release the opening. If you hear or feel a noise like opening a fizzy drink the wine needs more degassing.

Another simpler method is to taste a sample of the wine. Hold the wine in your mouth and you should be able to detect if there is carbon dioxide.

Some crisper or more dry wines may be difficult to discern acidity and residual CO2 so it takes some practice.