I Have Too Much Headspace In The Secondary Fermenter

Headspace in Secondary FermenterI am very new to wine making and have questions about the secondary fermenter and handling the headspace in the fermenter… I am sure it’s never good to let get oxygen in there with the wine but it never seems to work out for me. Can you please shed more light on this process and what’s the best way to deal with too much headspace in secondary fermenter. Use water? etc? And after racking secondary from 5 gal. and get lets say 4 1/4 gal? What you would use?

Name: Eric
State: La.
Hello Eric,

First of all, thanks for the great question. I’m sure there are others that have the same question about what to do when they have too much headspace in their secondary fermenter, so hopefully by sharing this we can help other home winemakers as well.

First we have to ask, why is having headspace even an issue? The reason is because oxygen is one of wine’s biggest enemies. Not only does it promote the oxidation of the wine, it promotes spoilage of the wine. Mold spores and bacteria thrive on oxygen. Either of these manifestations can be disastrous to a wine.

I am going to assume that the wine is in a carboy at this point. Topping up a wine that is in a bucket fermenter is not very practical since the ultimate goal is to reduce the surface contact area, not necessarily eliminate headspace. Regardless of how much you top up a bucket fermenter, the surface contact area essentially remains the same. If the wine is in a carboy, topping up will eventually get you into the neck of the carboy where there is little surface contact with the air.

I am also going to assume that the fermentation has completed. This is because during a fermentation having too much head-space is not an issue. While there is a fermentation occurring, the headspace is not filled with damaging air, but rather, CO2 gas from the fermentation. In other words, the headspace is harmless in this situation – as long as you keep the airlock in place.

Shop Wine Ingredient KitsThe last assumption I am going to make is that the wine is going to be in the secondary carboy for more than a week or two. If you are using a wine ingredient kit that can be bottled in 4 or 6 weeks from start to finish, then topping up is not something you need to be worried about. The wine is not still for a long enough period to be affected by oxidation.

Okay, so your fermentation has completed and you have it in a secondary fermenter, such as a carboy. You are waiting for it to clear, and you plan on this taking a few weeks if not longer.

Fortunately, there are several things you can do when you have too much headspace in a secondary fermenter. Which method you choose depends on the severity of the situation. Here is a list of what you can do to eliminate headspace in a secondary fermenter, starting with eliminating a minor headspace and ending with eliminating a major headspace:

  • Add Water: If the secondary fermenter is only short a cup or two, then adding water is perfectly okay. This small amount is not enough to alter the flavor or character of the wine to any noticeable degree. You will want to use distilled water for two reasons. First, all the free oxygen as been removed. This is a good thing. You do not want to add oxygen to the wine at this stage. Secondly, distilled water is free of chlorine and other chemicals you might find in tap water.
  • Buy CarboysAdd Water/Vodka Mix: If the headspace in your secondary fermenter is closer to a quart, you have to start considering the dilution of the alcohol when adding a water. For this reason you may want to use a distilled water/vodka mix. Choose a cheap vodka. It will be more flavorless than a brand name vodka. Grain alcohol can also be used for this purpose if it is available in your area. Assuming the vodka is 80 proof, use 1 cup (8 fl. oz.) for every half gallon of distilled water.
  • Add Similar Wine: If the headspace in the secondary fermenter is over a quart, then not only is the dilution of the alcohol an issue, but also acidity, body and flavor. For this reason you may want to top up the headspace with a similar wine. This could be a commercially made wine, but more economically, you could use some homemade wine that you have already bottled.
  • Add Glass Marbles: If the headspace is more like a half gallon, then displacement of the head-space with glass marbles my be the most practical solution. The marbles will need to be sanitized before putting them into the wine. Add them slowly to the carboy 2 or 3 at a time. Pouring them in rapidly could actually crack the bottom of the carboy. You would prefer smaller size marbles for this reason. Also, make sure they are player marbles and not decorative or aquarium marbles. These tend to chip easily.
  • Move Wine To Gallon Jugs: For situations where you have way too much headspace in the secondary fermenter, the only sensible way to handle it my be to move the wine into gallon jugs. You normally don’t like to be in such a position, but sometimes it can’t be avoided. The biggest problem with this is that the remainder to the gallons will be lost.
  • A Combination Of The Above: You may want to try more than one method for topping up the same wine. For example, if your wine is 4-1/4 gallons in a 5 gallon carboy. You could add some water/vodka mix, some wine and some glass marbles to make up the difference. This would be an option as opposed to breaking up the batch into gallon jugs.Shop Wine Making Kits

Having too much headspace in the secondary fermenter can be a problem. Fortunately, there are solutions. Doing any of these would be a better option than letting the wine sit still for weeks and months.

Happy Winemaking,
Ed Kraus
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.

37 thoughts on “I Have Too Much Headspace In The Secondary Fermenter

  1. Ed,
    I’m glad I read this. I thought that if I was going to condition my wine in my carboy for a few extra weeks or even a few months it would be possible to put an oxygen blanket in the head space and cap the carboy. For some reason I remember reading that CO2 was bad for wine like O2 is bad for beer.

    Also, any ideas on where to get marbles nowadays?


    • Old post, but thought I’d share anyway.
      At craft stores you can get those decorative glass “gems” that people put in vases for cheap

  2. Thanks for the tip on the marbles Ed. Can I put a blanket of CO2 in the headspace if I’m looking to buy some time? If for instance I need to leave it in the carboy for a month?

  3. Erik, purging the headspace with CO2 is never a bad thing and probably will be sufficient for a months time, however we have discovered that, unless the purge is almost perfect, it will not be as effective as removing the headspace.

  4. I am a home brewer but have had the same issue of head space. My solution is to brew a slightly larger batch and use a 6 gallon carboy for the primary fermentation and rack into a 5 gallon carboy. The 6 gallon carboy will have quite a bit of head space but that isn’t an issue during the primary fermentation due to the CO2. The 5 gallon carboy will have almost too little head space but you don’t have to worry about "boil over" during the secondary fermentation. This allows for the less and still gives you 5 gallons of final product.

  5. Wally, you will find malt called for from time to time in country-style recipes. The purpose for adding it is to increase the body of the wine. While the malt has non-complex sugars that will break down and ferment into alcohol, it also as complex sugars that the yeast will have a hard time with. These will remain in the finished wine and contribute to the body, and to a much lesser extent, the sweetness of the wine.

  6. Great information. Seems like your questios and answers are of more use to me now than a couple of years ago. Im fnally getting all my problems answered. Thanks

  7. Ed, argon gas works well for purging the air out of any headspace. Nitrogen will work too. However, do not you carbon dioxide. Unlike the other two gases it will saturate into the wine.

  8. Try florists for marbles! In my experience, they’re cheaper than playing marbles, though they’re maybe not quite as pretty. 🙂

  9. On the matter of excessive headspace after fermentation is complete. I allow my wine to clarify for 4 to 5 months after secondary (carboy ) fermentation is complete. I can’t count on residual co2 at this point due to numerous rackings. I’ve solved the problem of oxidation by injecting argon gas into the carboy…Argon is a very heavy gas and will quickly settle to the surface of the liquid thus providing a protective blanket. Hope this helps.


  10. I have used a large, food grade, sanitized zip-lock (or double zip-lock) bag filled with air and zipped tight to fill the head space. Makes the carboy custom fit to the contents and keeps oxygen out of contact with the wine.

  11. Emily, we do not recommend florist marbles. While they are cheap and will work, they are very brittle and break very easily. The chips of glass can be left behind with careful rackings, however we feel this posses a danger that the home winemaker should not be subjected to.

  12. I’ve heard for years that adding marbles is a great way to take up head space.

    But I’ve also heard that most marbles, which are mostly glass, available in the U.S. come from Mexico and that Mexican glass can contain high amounts of lead, which your CERTAINLY don’t want to put in your must or primary or secondary fermenter.

    How safe are marbles and are there alternatives like JUST PLAIN ROCKS from the creek in your back yard?

  13. JKV, lead should always be a concern, and one never knows for sure where it will be found. Here’s a quote I found from a thread on winemakingtalk.com at the following link:


    "This discussion about lead had me thinking bad thoughts. The glass beads I had were all made in China and marked non toxic. I did not believe the label so I went out and purchased lead test kits and tested samples of bags of the glass I was using. The unused glass all tested no lead as did the used glass."

    I did not know that lead testing kits were so easily available, but found one in seconds at this link:


    It might be worth it to pulverize a marble you intend to use and test it before doing so.

  14. What do you do when you have racked brandy into a carboy after fermentation and there is about 2 gallons of head space? thanks

  15. If going the route of using 1 gallon bottles for secondary process, you do NOT have to lose the remainder of the last gallon! Use 750 ml splits, or other sized wine bottles to complete final fermentation of an incomplete gallon, or do the marble, water, water + vodka, or wine tricks to complete the last gallon jug.

    Make notes of your recipe (measure VERY CAREFULLY) and how much volume of liquid goes from primary must (6.5 gallon bucket, or 7.8 gallon bucket) into secondary (6 gallon or 5 gallon carboy). Keep track of the temperature, the time, number of rackings, and of course, which yeast and how much of it was used. As you gain experience & your notebook grows, you should be able to make up just a little bit more juice than your carboy will hold, the extra useful for checking specific gravity, then taste testing.

    Those fancy gasses are expensive. I make CO2 using baking soda and vinegar in a bottle fitted with a drilled plug and a hose to fill the headspace ( i also use this for storing dried fruits, food in a Seal-a-Meal, etc.)

  16. Jill, the situation is really the same as if it were wine. The effects of oxidation on brandy will be slower than if it were wine because the alcohol level is higher, but eventually oxidation and spoilage will take hold of your brandy. You need to figure out a way to eliminate the head space.

  17. I use a vacuum pump to pull all of the air out of the headspace. I check it every once and a while after fermentation as co2 is released from the wine and needs to be re pumped. There are several pumps on the market but I believe the best suited for this is the allinone wine pump.

  18. The instructions for most kit wines tell you to not transfer any, any, any, sediment. Most people are paranoid about transferring any sediment. A little is OK. It settled out once and within a few days it will settle out again. If my math is correct, if you transfer 1%of the sediment the first racking and did one more racking and transferred 1% more, that would be .01% of the original amount of sediment. Not much at all. So please rack as much liquid as you can other than the last grunge. Why would you throw out good wine???????

    • I rack till the last possible clear drop and then collect all sediments in another tall narrow container/ bottle. Leave it for few days/weeks and i am again able to extract most of the wine leaving all solid deposit at bottom. The trick is in having as thin and tall bottle as possible. Why waste even a drop of your good wine!!

  19. I’ve been using food grade N2 for years to displace the air from the head space in carboys and never had a problem. For bulk aging in the carboys I just top off once a month.

  20. First time I heard using glass marbles; although, I have been doing so since the 2nd batch I’ve made. Remember that with a major head-space situation you will need a LOT of marbles because a gallon of marbles will offset just slightly more than a half gallon of wine. I have various size carboys – 6 gallon, 5 gallon, 3 gallon, 1 gallon and half gallon but have also used 1 liter wine bottles – which allows me to age the wine in appropriate size containers. Note that I always want to have at least an inch of marbles in the carboys to help capture sediment. I add water ONLY if I want to dilute a high alcohol (HOT) wine.

    • Hi Thom

      I just ordered 2 argon bottles. How much do you need to add and how often.

  21. Oh dang, I think I ruined 3 gallons! I topped off with juice 2 days ago. Is there anything I can do to save it?

    • If we are talking a few days there is no issue. If it’s been longer, it doesn’t mean the wine is automatically ruined. You will have to evaluate it. How’s the color? Smell? Etc.

  22. We are brewing a mead which called for a primary fermentation of the honey/yeast mixture in a fermentation bucket. Then you rack and add fruit for a secondary fermentation. This is in a wide mouth carboy which sits for 6 months. We have more headspace then is ideal. Fermentation has NOT stopped however. We are getting slow bubbles in the airlock. Should we be concerned about the headspace? Add marbles? Distilled water/vodka? I don’t think Argon or nitrogen gas will work as it is still fermenting.

    • JDTwig, as you know, during an active secondary fermentation, when the active fermentation is under an wine airlock, topping up is of no issue at all. This is because the fermentation creates CO2 gas that drives out the air that is in the airspace. This CO2 gas has no negative effect on the wine and is, in fact, a great protector of the wine. However, I would think after 6 months the fermentation would be complete. If you have not done so already, I would recommend taking a hydrometer reading to determine that.

  23. Hi Ed-

    I just racked my wine from the bucket fermentor to a 6 gallon carboy and I suspect there is a little over 4.5 gallons in my carboy. So I may need to use all 3 methods unless I purchase a smaller carboy for doing my next rack into. My question is you mention that it is not a problem to have headspace during fermentation. Does that mean only the yeast fermentation or does it also mean Malolactic fermentation? I am intending to start Malolactic fermentation after I rack off of my Gross Lee’s tomorrow.

    2nd question:
    I’m in Texas and the coldest we can tolerate in the house is 75*. I understand that to be too warm for MF. I have a wine fridge with a max temperature of 64*. I was thinking I would do a week of keeping the carboy chilled to 70* with cooler milk jugs insulated in external bucket just to activate the MF. Then transfer to the wine fridge for completion. Does this seem like a good strategy?

    I’m a total newbie, so any wisdom is appreciated!


    • You still have to be concerned, even with an MLF going on. There is not enough gas coming off an MLF to protect the wine.

      If you can keep the temperature at 75°, or even 76°, you should be fine. I don’t feel it would be necessary to go through them steps.

  24. This was good advice! But I did a kit wine that had about that much headspace in the carboy for secondary fermentation and the wine was terrible. I threw it out (I guess I could have tried letting it sit longer but I thought with that much surface area exposed to oxygen it was just going to make it worse. In any event, I cut my losses and am trying it again.)

    This time, I’m less worried about sediment in the wine and more concerned about getting the wine to the neck of the carboy. Even if I have a sediment problem, it will ruin 1-2 bottles if I’m careful to siphon without disturbing. If I have oxygen issues, the whole batch sucked. Other than my one misfire, this has been a fun hobby …and you get to drink wine when it’s done!

  25. I’m making 1 gallon each of lemon wine and cranberry wine. Is it okay to rack these wines into a wide mouth 1 gallon jar with an airlock in the lid for the second fermentation? Or should I stick to a 1 gallon carboy?

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