Degassing your wine is a key step in the final stages of the wine making process. Simply put it’s the process of removing suspended carbon dioxide left over from fermentation.

Before we talk about how to degas your wine let’s take a minute to talk about why it’s so important to get it done right.

Why Degassing is Important

It doesn’t seem like it should make a big difference, but leaving carbon dioxide in your wine can have three negative effects on your wine.

If you degas your wine you'll avoid quite a few problems later on.1. It leaves what should be a still wine carbonated.

While white wines often have a bit of fizz to them reds generally shouldn’t. Fizzy Zinfandel is not cool.

2. Suspended carbon dioxide prevents wine from properly clearing.

White wines are especially sensitive to the amount of suspended carbon dioxide. An improperly degassed white wine can have a haze to it that won’t clear through fining.

3. Carbon dioxide increases the sensation of acidity in wine. While the acid isn’t really there it tastes like it is.

Despite all these reasons to remove the carbon dioxide you don’t want to remove absolutely all of it. This can leave a wine tasting flabby and boring. For the amateur winemaker, however, this is rarely a problem.

Even sparkling wine is first made as a still wine and must be free of carbon dioxide prior to making a sparkling wine.

Usually not being able to remove enough carbon dioxide to avoid the three negative effects listed above is what gets us in trouble. So, let’s look at the best ways to degas your wine.

How to Degas Wine

Carbon dioxide can be removed from wine through three main methods: agitation, creating a vacuum, and time. Let’s look at each of these in turn.

Degassing Through Agitation

wine degassing toolUsually this is done with a type of stirring rod that attaches to a power drill. One of the more common degassing tools is the Fermtech Wine Whip (affiliate link).

Run the drill in one direction for 20-30 seconds and then abruptly reverse the direction of the drill so that you’re agitating in the other direction. Switch directions every 20-30 seconds

Be careful not to agitate the surface of the wine too much. Doing this can expose your wine to too much oxygen.

Most kits recommend a total of about 2-6 minutes of degassing when using a power drill agitator. However, it has been my experience (and that of many winemakers I know) that it can take up to 30 or 40 minutes of agitating to completely degas a wine.

To see a wine whip in action click here.

Create a Vacuum

A vacuum can be created by sealing off the top of your carboy and removing the air that is in there. This creates the vacuum.

When there’s negative pressure in the carboy the carbon dioxide will come out of suspension (form bubbles) and float to the top of the carboy. Thus you’ll have to have a way to maintain a vacuum so that all the carbon dioxide is removed.

I degassed a single bottle of wine using this method. I took my Vacuvin wine preserver vacuum, affixed the rubber top and proceeded to pump. It took quite a while to remove all the carbon dioxide. It’s hard to say how long it actually took because the wine wasn’t quite done fermenting when I had to put it in the bottle. Thus there was still CO2 being produce while I was using the vacuum.

One thing you should be wary of is how strong of a vacuum you create. Most wine preservation systems won’t allow you to create too strong of a vacuum. However, there are tools available that can.

The risk of having a vacuum that is too strong is that the carboy could implode. I’m not sure just how much negative pressure it can take so I can’t give you a har and fast number to go by. Just be careful. Glass, as you know, breaks but doesn’t bend so you won’t get any warnings.

Time

The easiest way to degas a wine is through patience. Given enough time all the carbon dioxide will come out of suspension and leave your wine.

This is the method employed by most wineries. Since they usually age their wine for months or years degassing is a lot less of a problem for them.

If you choose this method be sure that you’re not storing your wine on the lees. Rack off of all sediment and let the CO2 escape slowly. Should more sediment accumulate you’ll have to consider racking again to avoid off flavors from the decomposing yeast.

How to Know When You’re Done Degassing

There are two easy ways to determine if you’ve completely degassed your wine. The most commonly recommended method is by shaking a sample of the wine.

Take your test jar and fill it half way with a sample. Then put your hand or a bung plug over the opening and shake for thirty seconds or so. Open the test jar.

If you hear a burst of gas leaving the test jar you’re not done. If you hear nothing then you’ve completely degassed your wine.

The problem with this method is that you can still create that burst of pressure even if you’ve completely degassed because of the shaking. thus this isn’t the best method to use.

My preferred method is to taste the wine. If you taste bubbles it’s not degassed. No bubbles, no more gas.

Sometimes an acidic white wine can give the impression of carbonation so be careful. Also, the less carbon dioxide that is suspended in the wine the smaller the bubbles get. This makes them harder to detect.

While neither method is fool proof they will get you “close enough” to completely degassing your wine.

One word of caution. When you degas a kit wine they often have you complete the degassing process after adding a clarifier. Most clarifiers are not made of things that are nice to drink. While they may not taste bad or be bad for you the thought of drinking fish guts (isinglass) is just not pleasant. Degas before fining and be sure to stir it well after adding it.

Photo of sparkling wine by tristanf.

  • brycek

    When in the process should you do this? like three weeks, 2 months?

    • Great question brycek!

      Typically degassing in kit wines is done after fermentation has completed. At that point a clarifier is added and you run the degassing tool to both degas the wine and ensure that your clarifier is thoroughly mixed in.

      If you’re not working with a kit you can certainly follow the same process or you could wait until the wine is clear, rack it off the sediment and then fire up the degassing tool. Alternatively you could let your wine degas naturally. This takes three to six months though which is a long time, especially if this is one of your first wines.

      Let me know if there’s anything else I can do to help!

      -Matt Williams

      • brycek

        Thank you very much

        • john law

          i have added the clarifier but still have co2….will the co2 go over time…it is bottled and i have loosened the scew tops to allow gas to escape……thanks john

          • Hi John, yes the carbon dioxide will leave over time. Be careful with your screw tops loosened as you don’t want to get into trouble with oxidation and spoilage micro organisms. They do make drilled plugs that will fit a wine bottle so you could put an airlock on the bottle. This may or may not be feasible depending upon how many bottles you have.

            I would suggest holding off on bottling next time until the wine is completely clear and degassed. In general what goes into the bottle stays in the bottle until you pour a glass.

            I hope this helps John! Cheers!
            -Matt

  • Andre

    I am a newbie when it comes to making wine. I am in the process of making my first kit. I was thinking about the degassing problem. My instructions tell me to rack the wine into my primary fermenter (a 5 gal pail) then stir it for 10 min. each time over a 2 to 3 day period. This seems laborious to me. I was thinking about purchasing a long spoon (they are very cheap) cutting the small end off and using it in my drill. Any thoughts about doing that. If I let the wine degass naturally over a period of 6 months can I bottle it and hope the degassing process will take place in the bottle?

    • Hi Andre, degassing is a challenge and it can certainly be laborious. The trick to it though is making sure your wine is in the 72-75F temperature range. Any cooler and your wine will really hang on to that suspended carbon dioxide. In warmer temperatures it readily lets it go.

      Using a spoon or an actual drill attachment (like this one: http://winemakersacademy.com/wine-whip) is a great way to speed up the process. I get the best results by reversing the drill direction every 30 seconds. Let the drill stop spinning but not the wine before reversing. This ensures maximum agitation in the wine but without burning out your drill motor. Also, keep the agitation below the free surface of the wine to avoid taking on oxygen.

      Lastly, I’ve always found that whatever goes into the bottle stays in the bottle. So if you bottle a wine with sediment or carbon dioxide in it you’ll find that it’s still there even after a couple years in the bottle. I have a shiraz that I didn’t degas all the way and to date it is still bubbly and doesn’t taste all that great.

      Your wine can degas naturally over time, however, the storage temperature makes a big big difference. I hope this helps Andre!

      -Matt

  • NIck DeNora

    Hi

    My Riesling White wine is amber and
    carbonated? A little off tasting? Is it bad? I let it go 6 months before 2nd
    racking… I racked it a month ago and put in isinglass and I just racked it now,
    put a little potassium metabisulfate in there…

    And while I was
    transferring,, it foamed like crazy… its just a bit dark?

    Please advise?

    Thanks, Nick

    • Hi Nick, I’m sorry to hear that things are tasting a bit off. If the wine sat in a carboy for six months that isn’t necessarily bad, however, you may have picked up off flavors from decaying yeast if it threw any sediment while in the carboy.

      Another possibility is that it could have come into contact with some sort of spoilage micro-organism. Was there any hint of sulfur (burnt match or bad eggs)? Did you pick up any vinegar flavors or something akin to bad fruit?

      The foaming and carbonation after that amount of time is what’s concerning me. Spoilage micro-organisms do a fermentation of sorts and will produce carbon dioxide so when a still wine starts bubbling again something may indeed be off.

      You might find some answers by taking a small sample to a local winemaking supply shop to see if they can identify any off odors.

      Let me know what you think is going on.

      -Matt