The goal of degassing wine is to remove the carbon dioxide from it. If you’re using a home winemaking kit, especially one that allows you to create batches in a short time frame, there’s almost certainly a specific step for degassing and possibly some tools to complete the job. But where did that unwanted carbon dioxide come from? Why is it important to degas wine and is it strictly necessary? We’ll answer these and other questions related to this important step in winemaking and describe specific methods for degassing wine.
Where Did the Carbon Dioxide Come From?
During the fermentation process, yeast converts the grape sugars into alcohol. This reaction also produces carbon dioxide, which is the same gas that gives soda its fizz. The must, which includes the crushed grapes, seeds, stems, and juices, will bubble as these gases are created during fermentation.
As all those bubbles pop at the surface, they’re releasing a portion of that carbon dioxide, of course. Some of the carbon dioxide will remain suspended in solution in the wine, as well. It’s this suspended gas that you’ll get rid of through the degassing steps.
Is Degassing Homemade Wine Necessary?
Well… no. Strictly speaking, it’s not completely necessary to do a manual degassing step for your homemade wine. In fact, home winemakers who have been producing wines for decades say that the old kits didn’t even mention doing such a thing. Instead, they just allowed their wines to naturally degas over time just like most commercial wineries do.
Commercial wineries make so much wine at once that it’s more efficient to just wait and let the carbon dioxide naturally escape the wine on its own. Bulk aging the wine this way spares them the expense and the mess of manually degassing each batch.
You can skip the degassing step, as well, but only if you’re willing to wait. If you’ve grabbed a kit that promises you drinkable wine in 4-6 weeks, however, you’re going to have to do a degassing step if you want to be enjoying that first glass in the promised time frame. Certainly any manipulation of the wine, like transferring it from container to container, racking, etc, will all release some portion of trapped carbon dioxide. The gas will also slowly release if you’re planning to mature the wine in a barrel for a long time.
If you want to drink your new wine soon, however, the answer is yes. You’ll need to do a degassing step.
Why it’s Important to Degas Your Wine (and What Happens if You Don’t)
If you don’t degas your wine, it’s definitely not going to look or taste its best. Without degassing:
1. Your wine won’t clear properly during the fining step.
Right after fermentation, your wine will be very cloudy. A lot of this haze is yeast and sediment that will sink if given enough time. Most kits also include fining agents to help clarify the wine, so you can more easily rack the wine off the sediment.
If the wine hasn’t been degassed, the carbonation will interfere with these processes. Think about how there are bubbles constantly rising to the top of a glass of soda, for example. A similar thing happens in wine loaded with carbon dioxide. Those bubbles would constantly stir up the sediment as you’re waiting for the haze to settle out.
2. Your wine will be carbonated.
This is not ideal. Sometimes white wines have a little bit of a fizzy, tongue-tingling texture to them, but they are always degassed. (So are sparkling wines, which we’ll discuss in the next section.) Red wines shouldn’t give any sense of carbonation at all when you drink them. So, you must degas to get rid of all that dissolved carbon dioxide.
3. Your wine may taste too acidic.
Not properly degassing a wine can leave it tasting overly acidic. This is because of the way dissolved carbon dioxide impacts the wine chemistry. Carbon dioxide reduces the pH of solutions it’s dissolved in, which means it becomes more acidic. This isn’t the same acidity as the fresh, tart, and sour flavors that come from the wine grapes.
Are Sparkling Wines Degassed?
Yes, they are! There are several different methods of creating sparkling wines, but in the traditional method, there is a second fermentation step that adds the carbonation. The first fermentation yields a ‘still wine,’ which has been degassed. Then the second fermentation adds the carbon dioxide that creates the bubbliness we all associate with sparkling wines.
When is it Time to Degas?
You should plan to degas your wine once you’re certain that fermentation is complete. If fermentation is still happening, the yeast will still be releasing carbon dioxide into the wine. So, if you do it too early, you’re simply going to have to do it again. Besides, if fermentation is incomplete when you go to bottle your wine, you’re going to have corks popping everywhere. To determine whether your wine is totally done fermenting:
1. Look for visual cues.
Do you see bubbling? If you’re using an airlock like the one below and can see bubbles moving through it, then the answer is definitely no. It’s not time to degas yet, because fermentation is still happening.
Don’t see bubbles? That is a good sign, but there could be fermentation happening. It may just be that it’s not enough to see bubbles, so you’ll need to investigate further.
2. Measure the specific gravity.
This is the surest way to determine whether fermentation is complete. You can use a hydrometer like the one below to measure the specific gravity of your wine, which measures how its density compares to that of water.
Why does the specific gravity matter? Grape juice is denser than water, so at the beginning of the fermentation process, the specific gravity will be greater than 1.0. As fermentation takes place and the sugars are converted to water and alcohol, the density will decrease.
You should take specific gravity readings once every several days (or once a week) until you get 2-3 readings that are the same. You’ll want to see a final specific gravity around .992 and .996.
Important note: some winemaking kits say to degas your wine after the clearing/fining agent step. Don’t do this — you should definitely degas first, then do the fining agent steps second. This is in part because you may want to taste the wine to see if it’s fully degassed. If it contains the fining agent, it’s going to taste gross.
Methods of Degassing Wine
Once you’re confident that fermentation is complete, you’re ready to get rid of all that pesky carbon dioxide. There are three common methods for degassing wine. Note that these should also be done while the wine is held at a temperature of or above 70°F. If the wine is too cold, the carbon dioxide is going to be more likely to stay in solution. Note, you don’t want the wine to be hot! Aim for a temperature of about 75°F.
Agitation (aka The Whip)
The carbon dioxide that remains dissolved in the wine after all the bubbling has stopped is only lightly bound in solution. Even gentle agitation of the wine, like stirring it with a spoon, will help get the gas molecules to the surface where they can be released.
The amount of carbon dioxide varies from batch to batch, so it’s hard to guess how much stirring it might take to release it all. It could take minutes or hours depending on the amount and on how effective your stirring technique is.
Fortunately, some clever people came up with tools to speed this process up. By attaching a specially-designed stirring rod to a power drill, you can let electricity do all the work for you. There are several different styles of stirring rods available.
Just attach one of these paddles to your power drill, put it in the wine, and turn on the power. The manufacturer instructions for each paddle will give you a sense of how long you should do this. You should also try not to disturb the surface of the wine too much while you stir, as it will introduce oxygen.
You can also attempt to remove the residual carbon dioxide from homemade wine by using a vacuum. This will help draw the tiniest gas bubbles from the wine to the surface, where they’ll be released into the air.
You’ll need to maintain a vacuum in the container in order for this to work properly and ensure all the carbon dioxide is released from the wine. There are a few ways to do this, depending on the volume and type of container.
If you’re just dealing with a single bottle of wine, you can try using a wine preserver vacuum like this Vacuvin. Apparently this works, but can take a long time.
For larger volumes, you can try a system like this All in One Wine Pump:
This system is useful for a variety of other applications in home winemaking, as well. It allows you to filter your wines, which can stop any residual fermentation, and rack them at the same time. Since it’s a closed system, there’s less contact with oxygen. The company also offers custom accessories to fit almost every size and shape of bottle.
If DIY systems are more your style, you can also assemble your own vacuum pump system to degas your homemade wines. If you go this route, be careful. You should make sure that all your materials can withstand the amount of vacuum pressure you’re subjecting the system to. A glass carboy won’t give you much indication that it’s about to crack or implode until it actually happens. Then you’ll have an enormous mess on your hands. All your hard work up until that point, not to mention all your delicious wine, will be lost.
Time and Patience (Natural Degassing)
This is the most traditional way to degas wine, not to mention the most natural one. All you do is wait. Sure, it requires time and patience, but given enough of each, all that carbon dioxide will make its way out of the wine on its own.
As we mentioned above, this is how most wineries handle degassing. They’re aging their wines in bulk for months or years, so it’s the easiest solution. In fact, they probably don’t think much about carbon dioxide at all, since the long waits are part of their normal process of winemaking.
This is also a legitimate strategy for home winemakers. You will have to be patient, however. This is probably the best plan as you begin making wine in larger volumes.
When is Degassing Complete?
There are a few ways to test whether degassing of your homemade wine is complete, or at least close enough to produce a palatable wine. Sometimes it takes longer than the kits suggest to fully remove the carbon dioxide from the wine.
The first is to taste it your wine. If you feel bubbles on your tongue, you have more degassing to do. When wines are acidic, your tongue will sometimes tingle, but that will feel a bit different than carbonation. If you’re unsure whether it’s residual carbonation or natural acidity from the grapes, you can try tasting your wine side by side with a similar wine that you know has been perfectly degassed. Grab a commercially produced wine, for example. That may help you decide whether your wine is ready or not.
Another good test is to take a sample of your wine and swirl or shake it. Collect a small amount in a jar and give it a swirl. (This is like agitation degassing on a smaller scale.) When you stop, check the surface of the wine for bubbling which would indicate that there’s still carbon dioxide being released.
You can also put a lid on your test jar and give the wine a very vigorous shake. The shaking itself can introduce bubbles, too, of course, so you’ll need to observe carefully. If you hear a burst of gas releasing when you open the lid, that’s another good indication that there’s still more degassing needed.
Although none of these methods are perfect, they’ll get you close to the answer. When in doubt, you can always degas longer. Note that it’s unlikely that you’ll get 100% removal of carbon dioxide and that is fine. You’ll just want to get close enough that it’s not going to impact the flavor and texture of your wine.
A Final Note on Handling Degassed Wine
After degassing, your homemade wine will be vulnerable to oxidation, so it’s important to protect it. Transfer it to a carboy and add the stabilizers and clarifiers according to your kit instructions.
For More Home Winemaking Tips
Are you new to home winemaking? Whether you’re dipping into this fantastic hobby for the first time or still wondering whether you should take the plunge, we’re here to help. Check out some of these other excellent posts from I Love Wine:
- Best Guides for Making Your Own Wine. We share some of the best winemaking guides out there, covering the principles of winemaking, recipes for wine, and guides for outfitting a home winery.
- How to Stop Fermentation During Winemaking. This article explores ways to stop that fermentation step. It’s generally recommended that you let fermentation hit its natural endpoint, but if you want to try to stop it early, we explain how.
- How to Make Wine Sweeter. This topic is related to the last one. If you get a batch of wine that’s too dry after that fermentation step, we’ll guide you through the ways of sweetening it after the fact.
- The Best Wine Filters for Winemakers. We also review winemaking equipment! In this guide, we review and make recommendations on wine filters for winemakers. Even if you’re not filtering to stop fermentation, this step will remove sediment and give your homemade stunning clarity. We include setups that will filter by the glass or the barrel.
And, to further your wine education:
- Best Wine Books. Our list of best wine books that are not only educational, but a pleasure to read. All will be lovely additions to your collection and take your wine knowledge to the next level.
- Best Wine Magazines. Wine magazines are also an excellent source of knowledge and inspiration. Some of these offer fantastic wine reviews, as well, to keep you in the know as your passion for wine grows.
- Best Sommelier Courses. Ready to take on an entirely different skill set? We describe sommelier certification courses, how much they cost, and where you can take them. Even if you’re not seriously considering becoming a sommelier, you’ll greatly enhance your palate through this course of study.