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.
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
Usually 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.
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.