At the very center of wine making is the process of fermentation. Fermentation occurs because the yeast want to consume the sugars in a wine must. As a result, the sugars are converted into both alcohol and CO2 gas by the fermentation. Normally as winemakers, we are concerned about the alcohol, but in this post we are going to change directions and talk a little about the gas.
Almost all of the CO2 produced during a fermentation dissipates into the air and goes away very quickly, but not all of it. Any liquid – wine included – has the ability to hold some CO2 gas for a period of time. It stays saturated in the wine. This CO2 gas is the same stuff that puts the fizzy in soda pop, beer and even the sparkle in sparkling wines, but when it comes to still wines we don’t want CO2 gas to do anything but be gone.
A Little Degassing Background
When I first started making wine, degassing was not even a word in the winemaker’s vocabulary. Finished homemade wines always sat around long enough in bulk glass jugs clearing and aging and whatnot, that they degassed themselves naturally with time. Wines back then needed extra time, and along with this time the wine was able to release all the CO2 gas it contained.
But things changed when 28 day and 6 week wine kits came onto the scene. These kits allowed the home winemaker to bottle their wines in a relatively short amount of time. This is not enough time for the CO2 gas to escape on its own. Because of this, the wine kit producers added the extra step of degassing in their directions they included in the kit.
How Do You Degas A Wine?
A portion of the CO2 gas can stay saturated in a wine indefinitely because the gas molecules will lightly bond with the wine, but by agitating the wine with something as simple as a stirring spoon, the gas molecules will start to release and float to the surface and dissipate. If you stir the wine long enough, all but an untraceable amount of the CO2 gas will be released. The amount of time it takes to degas a homemade wine the with a stirring spoon can vary greatly. It could take a few minutes or a few hours depending on how much CO2 is still in the wine at this point.
One way to speed up the process is to use a degassing/mixing paddle. The paddle attaches to a hand drill just like a drill bit would. This significantly reduces the amount of labor and time needed to degas a wine.
Another way of degassing a homemade wine it by putting the wine under a vacuum. This can be done with a wine preserving vacuum pump, like our Vacuvin Wine Saver or any other hand-held wine preservation system to degas the wine. By putting the vacuum pump directly over the air-lock hole of a rubber stopper, you can literally suck the CO2 gas out of a glass jug.
Ed Kraus is a 3rd generation home brewer/winemaker and has been an owner of E. C. Kraus since 1999. He has been helping individuals make better wine and beer for over 25 years.
I’ve been stirring my wine for 4 days now, 4 to 5 times a day for about a minute and I still have foam or bubbles. Do I just keep this process up until there are no bubbles or did I screw up somewhere?
There is not reason to wait between degassing periods. Just keep stirring until no more bubbles are releasing. It is important to understand that if you splash the wine while stirring, you will saturate some air into the wine. This will cause bubbling/foaming as well. So I would look closely to see if this is now the cause of the bubbles. Something else that is not mentioned in the above article is that the colder the liquid the tighter the bond between the CO2 and the wine. If your wine is very cold the could be the reason that your wine is reluctantly giving up the CO2. Temporarily warm the wine up ito 70F if this is the case.
Hi there, my im making a strawberry wine, my original gravity was 1.114 and final is 1.002 which adds up to make 14.7 abv its veeery strong and i will backsweeten, have i done anything wrong, are my readings odd?
how would you recommend warming it up? Ours it taking hours..and I’m pretty sure its because the temp of the wine is much lower than when we started. I dont know any room in our house that is 72 or higher.
I use a small hallogen spot light . think its 75 or 100 watts. when on it burns hot so I set it about 1 foot away to start and pull it away as temperature rises, simple and easy to control. once the fermentation is racing I turn the light off and let mother nature do the rest
Please don’t misunderstand our previous comment about temperature. You do not want the wine warm or hot. You just don’t want it cold.
Does it help to pour the wine from one container to another to degas it?Thnxx
Tom, this is a great question. You could pour the wine back and forth and it would release the CO2 from the wine, but it would also introduce excessive oxygen into the wine. This will cause the wine to eventually oxidize. If you have done this already, I would recommend adding a dose of metabisulfite to the wine to help drive out some of the oxygen. The goal with degassing is to agitate the wine without splashing. It is the splashing that allows air to saturate into the wine.
Hello, I use your kits however am in no hurry to bottle preferring at least six months of age time. After initial fermentation in a six gallon plastic bucket, I transfer to glass carbouys. I then pour into a fresh carbouy at about a month to get the wine off the sediment. How can I transfer off the sediment again at three months and degas without adding oxygen? And why is oxygen so bad? What are the effects to the wine? My prefernece is not to add sulfites. Please advise. Thank you.
Ray, the reason oxygen is so bad is because it oxidizes the wine. Like an apple that’s been bit will turn brown, a wine will turn brown as well. I would suggest getting a degassing/mixing paddle. This will allow you to degas without getting too much air into the wine. I understand that you do not want to use sulfites in your wine. Please realize that not doing so will shorten the life of your wine. You might want to take a look at the article "Controlling Oxidation When Making Wine" that is listed on this blog: http://blog.eckraus.com/wine-making-tricks-and-tips/controlling-oxidation-making-wine
I have made wine from fresh grapes about 500lb,this past spring (california grapes),and now I am at the scond fermantations .for some reason in one of the 5gal, bottle there is a white residue on the top of the wine. can you tell me what could it be? thank you, Matty.
Matty, it’s hard to know for sure without seeing it, but most likely it is a bacterial infection of some kind. This can easily be stopped by a dosing of sulfites. If you have not add sulfites to your other vessels, I would recommend that as well.
As you said the process of degassing is not necessary in "normal" wine making. Can this step be avoided by using another yeast?
I found that even after 9 months the CO2 is still in the wine so I am wondering what is causing this.
Hans, regardless of the wine yeast you use the CO2 given off will be just about identical. The variation is only 2% or 3% with these yeast.
Perhaps I should rephrase my question. I do not understand why the CO2 does not leave the wine by itself even after a long time. Is that related to the concentrated juice or is it related to the yeast?
I am hoping that by using a different yeast the CO2 will leave the wine as in normal wine making. I do not need a yeast that can ferment 5 gallons in 6 days. I can wait a bit longer.
Hans, the CO2 that remains in your wine has nothing to do with which yeast you use or concentrate verses fresh juice. Not all CO2 wants to leave wine naturally. Some of it will stay if left alone. ‘How much’ depends on temperature of the liquid. The cooler your wine is the more CO2 gas will want to stay in the wine. This is true of any liquid.
In the middle of October I started twenty-five gallons of concord wine from juice. The only thing I added was one pound of sugar per gal. and 1 tsp. of nutrient per gal. Two months later it still looks like it’s going through its secondary, (natural) fermentation. My question is, should I now end the MLF by sulfiting and racking the wine or should I just wait it out?
If the wine is sitting on any sediment I would rack it off of it into a clean fermenter, but other than that your best off to leave the wine be.
I have been making wine off and on for 30 years and have never degassed . I just let my wine age in the carboy 4 to 6 months before bottling . Also , the only additive in the kit I use is the yeast , and sometimes the sulpate if I intend to keep the wine more than a year or two. All the other stuff is unnecessary if you age your wine properly.
I find the wine has a sweeter,purer taste without the sulphate.
Thanks Ed. Probably just what I needed to know. Very informative. I have a beery wine that wont stop "gasing". have stired it several times with is drill and wisk and use a Vaccum pump in the mean time but the gas just keep producing. Temp has perhaps been a bit cold, about 19-20 C and I will ad a pinch Metabisulphite. Any other suggestions will be greatly appreciated. //tj
It’s still fermenting that is why your wine is still “gassing ” It’s self
Tom, before adding the sulfite, I would check the wine with a hydrometer to see if the fermentation ever finished with the sugars. You could have a lingering fermentation. If this is not the case, it is possible that the case is the result of a bacterial infection. In which case the addition of sulfites will remedy very easily and quickly.
Thanks. I actually had done what you suggested and found the fermentation slowly restarting. A small decreace in the sp.gr. I also added a heating pad and some sulphite. It is still gasing, perhaps a bit less. Bacterial infection, i suppose it will eventually kill the batch..
It is a 23 l batch, how much sulphite do you suggest I should add?
Tom, we recommend 1/16 teaspoon to each U.S. Gallon, That comes out to three 1/8th teaspoons to 23 liters.
Thanks again Ed. I think that should be 3/8’s tsp. 23l = 6 US gall. which is about what I added.
I racked it again before adding the sulphite but it is still gassing pretty good. I dont want to loose this batch, it’s nice hand picked Saskatoon’s. You may call them bearberries, Juneberries??
When is the time to de-gas wine. I have made wines from, bananas, bananas and peaches, grapes… I left them sit after racking to bulk age until I need the carboys for the next years batch. But my bottled wines are definitely carrying over too much CO2. So when in the process should I de-gas them. I have a de-gassing wipe. Kits tell me when to do it.
Ted, if you are bulk aging your wine then I would suggest that you wait to degas when you are ready to bottle the wine. Rack the wine off the sediment; degas the wine; add sulfites; and bottle. It is important to rack off the sediment first. It is also important to degas before adding any sulfites to the wine such as potassium metabisulfite.
It is interesting how degassing wasn’t always a process that you had to necessarily think about. Stirring the wine is such a simple method, but this is an imperative part of the process if you want to make quality wine. Thank you for such a detailed article on making wine and all of the factors that go into it. I will definitely be apply your tips the next time I make wine.
why is it important to degas the wine before adding sulfites to the wine?
Andrew, if you add the sulfites and then degas the wine the stirring action of degassing will cause the sulfites to dissipate and leave the wine.
Can you over degas the wine? I’m making my first batch of wine and degassed until the bubbling stopped. Then once in the carboy I used a vacuvin to get what I perceive the rest of the gas.
Michael, the only caution i would give you is that if you use the vacuvin, once all of the CO2 is removed then it will start to remove aroma.
I have racked my wine and added sulfites BEFORE degassing my wine. Should I rack again, degas and add more sulfites?
Ashley, unless there is sediment at the bottom of the fermenter, you do not need to rack again before you degas. You will need to add sulfites again when you are ready to bottle the wine.
I just finished pressing 5 lugs of grapes to give me about 10-12 gallons of meritage blend. It just completed the primary fermentation and i am about to rack it to carboys. I plan on leaving it there until secondary fermentation completes and then rack and transfer it for 1-2 months in an 10 Gallon oak barrel. When should I be degassing my wine? and should i add any isingglass? Thanks by the way your website / blogs are very helpful.
Juan, degassing of the wine normally takes place right after the fermentation completes. If you want to add more polish to the wine, then by all means go ahead and treat the wine with Isinglass. We are glad the our information has been helpful. If we can be of further assistance, please let us know.
Simply put, 4 gallons of liquid in a 6 gallon, do I HAVE to degas and/or stir? Not my first liquid rodeo, but I’ve never used such procedures or “tools” … Thanks.
Bill, before any wine is bottled it should be degassed. If the wine is bottled before the gas leaves the wine, the wine will be fizzy/sparkling and could cause the corks to pop out or worse. You do not want gas trapped int the wine when it is bottled. As the article says, if the wine sits around long enough before bottling it will degas itself naturally. If you are not making 4-6 week kits, your wine might be degassing itself.
my;my,my…all this degassing,sulfites & other steps are making wine making a major chore…been making homade wine for I’d guess going on 35-40 years…five things needed for (have never had any complaints, returns, or negative inputs about the first bottle)homade wine; good water, fruit, sugar, yeast & time…other than that, I’d give it up & spend $4-5.00 on a bottle of Boone’s farm strawberry hill…ha!, really exhausted from just reading all this stuff bout gassing…justice passed a little gas naturally; tilt, bwoop, we be thru now…lol
Why is CO2 more concentrated in kit wines and what makes it to be trapped in the wine?
John, it isn’t that there is more CO2 produced in wine kits. It is that you are bottling wine kits normally in about 4-6 weeks, so the wine does not have time to degas itself naturally. If the wine is allowed to sit around a while before bottling, most of the CO2 will leave on its own.
Hi Ed. I’m thinking of bulk aging my wine (Cellar craft18L kit ) in a carboy after racking it off the second fermentation for an extra month or two, rather than gassing it and bottling it it right away. I’ve already added the suphate packet. Will I need to add more sulfate when I bottle it in two or three months?
Mike, yes, once you are ready to bottle the wine after bulk aging you will need to add another dose of sulfites to prevent spoilage of the wine.
Adding Sulfites Before Bottling
I have been making apricot wine since 1994 – about 600 gallons over the years (have a certified organic apricot orchard) and have never sulfited – I depend upon boiling water sterilizing. I have had only 1 gallon container go bad after a family member contaminated it by drinking directly from the container. Made very good and very strong apricot vinegar. I have had a number of 750 ml bottles that have aged 15 to 20 years before cracking open, all were still excellent! In a nutshell, you CAN do without the sulfite if you are very careful!