To Use, Or Not To Use An Air Lock On A Wine Fermentation?

3 Airlocks In SilhouetteOn many occasions we have been asked this simple question, “Should a wine making fermenter be sealed with an air-lock during the first few days of fermentation — the primary fermentation — or should it be left open, exposed to the air?”

The Conflict
This question arises because there is so much conflicting information floating around in wine making books, on the internet and in other places as to which method is correct. In fact, even our own wine making website recommends just covering the primary fermentation with a thin towel, while the instructions that come with the wine ingredient kits we sell recommend using an air-lock.

Even commercial wineries are not consistent in this area. While most wineries will put white wines under an air-lock and expose red wines to air, there are many, many wineries that will do the very opposite.

My Recomendation
The reason I recommend leaving the wine must exposed to air during the primary fermentation is because this method leads a more vigorous fermentation, one that is able to complete more thoroughly and quickly. Wine making kit producers recommend sealing up the primary fermentation with an air-lock because they are more concerned about eliminating any risk of spoilage than providing the fastest fermentation possible.

Spoilage can be of concern on those rare occasions when the fermentation does not start in a timely manner, but if the fermentation takes off quickly, spoilage is of no issue. The activity of the yeast will easily protect the must by impeding the growth of any unwanted organisms.

So, What Should You Do?
Shop Wine AirlocksWhile I recommend using a thin, clean towel to cover the fermenter during the primary fermentation and nothing more, if you are concerned about your fermentation not starting there is a compromising method you could follow:

When you first pitch the wine yeast into the must, put an air-lock on the fermenter. After a few hours, once you see that the fermentation has begun–indicated by activity or foam on the surface–you can then take the air-lock off and safely allow air to get to the must. This is, in a sense, giving you the best of both worlds–the protection and an invigorated wine making fermentation.

As A Side Note:
It is important to note that an air-lock should always be used after the must has gone into its secondary fermentation. This is in agreement with most. This usually starts around the fifth or sixth day, or when the first racking is performed. It is about this time you will notice the fermentation’s activity level starting to taper off.
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.

5 thoughts on “To Use, Or Not To Use An Air Lock On A Wine Fermentation?

  1. Hello, how bad did i mess up here.
    I boiled my water well it wasnt really boiling it was just hot
    and desolved my sugar and added the water to my plums i didnt add the yeast tell after things cooled down, using an are lock i was geting perks within a half an hour and withenan hour of adding the yeast i was getting a burp every five second and was increasing activity rather rapid. it seems to be doing it, i am new at this. is there anything i should watch out for? Do you think it will be ok? should i throw it out and start over? thank you


    • David, there is no need to discard your wine. Just because you used an airlock during the primary stage does not necessarily mean there will be issues with the fermentation. From what you have described, it sounds like the fermentation is progressing along. If you are still in the primary stage, you can still remove the lid to allow oxygen to reach the yeast.

  2. I use a 5 gallon bucket to make 5 gallons of wine. That leaves only about a 1/2 inch space at the top when the must is ready to be pinched. I never use an air lock at any time during first second or third racking’s before bottling. I only place the lid of the bucket over the bucket from start to finish. But I do not snap it down. I just let it cover the must. That leaves about 1 full inch of air space after I pinch the must. I do not stir the yeast into the must. I just sprinkle it over the top of the must and let float on its own and start on its own. I do not rack it until I get a 0.990 reading. That’s when I put in the campden tablets and rack it for the first time the next day better than twenty four hours later. After I racked it into a clean bucket. I snap the cover down tight and let it set for another three or four days and rack it again for the second time. I leave it set again for another three or four days with the cover snapped on tight. After that I rack it again for the third time into a clean bucket. Then I sulfate it and bottle it into 1 gallon jars rather I sweetened it back then or not. Because you can sweeten back a wine anytime after it is done. Even store bought bottled wines if there to dry to your liking.

  3. I would worry that during the time after the vigorous ferment and time to bottle there would be some oxidation occurring especially with the absence of sulfite. Oxidation is a fleeting thing, some people don’t mind it in their wine. Some sweet wines ie sherries, and the like are purposely oxidized for the distinctive flavor.
    For my taste I don’t want any oxidation period. Unless my wine is really high in sugar and alcohol.

  4. I just lay the cover on my primary without snapping it down until the fifth or sixth or seventh day. After racking into secondary, I seal it up with an airlock. It stays under airlock for all additional rackings up until bottling day. I have never had a problem doing it this way even when fermentation has not gotten underway for 48 hours. Red or white, there’s enough gas sitting on the must during primary fermentation that there’s really no need to seal it up as long as you get it into the secondary before fermentation slows to a crawl.

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