I did my first brew (all grain), some things were complicated to achieve and finished at 4 o'clock in the morning because I decided to start at 10 pm (big mistake).

At the end of it all, after I sanitize equipment and put the wort in the fermenter bucket, I sealed and placed the arilock.

Only to realize that I did not put water in the airlock after only seven days of fermentation!

What can I do now? A second fermentation? Set everything out and redo my beer?

The airlock ("S" type) that I use is this: http://ebrew.com/Products_A/airlock_s-type.jpg

  • I've forgot to put liquid in the airlock two times, and one of those times the wort became infected. Oct 5, 2014 at 21:16
  • I read all the comments and very fruitful information. First of all thanks for your time. I have an additional separate question. I did the same thing and forgot to put water in the airlock. After 2 weeks later I added some sanitized water and decided to keep the beer one more week. And this weekend it will be the third week in the bucket. Is it a good decision? Do you have any special recommendation for the bottling? May 24, 2019 at 8:49

4 Answers 4


Seal the beer off from oxygen as soon as possible. If you decide to use the airlock, use sanitized water only.

If you have access to CO2, put a layer of the gas over your beer as soon as possible (then close it off). If you've achieved your desired final gravity and you don't need to let it sit in the fermenter any longer, you could also bottle it or keg it right away.

If you're lucky, you shouldn't need to do anything. Because CO2 is heavier than oxygen, and CO2 is a byproduct of fermentation, during fermentation, and for some time after fermentation, there will be a layer of CO2 protecting your beer from oxygen, as long as you don't mess with it too much.

To decide whether your ruined your beer or not, John Palmer's site may be helpful (http://www.howtobrew.com/section4/chapter21.html)

  • 5
    You don't have to use "sanitized water only" in an airlock. AAMOF, I never do and I've never had a problem.
    – Denny Conn
    Oct 4, 2014 at 16:01
  • @DennyConn, you may not have had an issue, but using sanitized water or StarSan or vodka doesn't hurt. I know that I have had suckback from my airlock (temperature rapidly changed, creating suction), and I would hate to get an infection just because I didn't use StarSan in my airlock. The same goes with krausen from rapid fermentation in the airlock; you just never know. My mantra is, "if it can or will come in contact with the beer, make sure it's sanitized." edit: To clarify, I use StarSan in my airlock. If a little gets sucked in, it's just yeast food! Oct 6, 2014 at 15:30
  • No, it doesn't hurt, but if your water is clean it doesn't help either.
    – Denny Conn
    Oct 6, 2014 at 15:39
  • I put vodka in my airlock. Oct 7, 2014 at 7:49
  • @derek.cormier: If you get suckback from an airlock, you've filled it too high. You won't get suckback from a properly-filled airlock.
    – Jeff Roe
    May 28, 2019 at 5:57

RDWHAHB. Your beer is probably fine. Gases generally flow out during primary fermentation, not draw in. If you want to leave the beer in primary for a while, put some water in the airlock. If you want to rack to secondary, rack. Now actually might be a good time to take a hydrometer sample. Taste the sample to convince yourself that your beer is OK.


Your beer is almost certainly fine, and you don't need to do anything except fill the airlock with water, and attach it to the fermenter. The release of CO2 in the fermenting beer creates positive pressure within the fermenter, which will help keep out oxygen and spoilage organisms. After fermentation is complete, it's possible for gas and bugs to enter through the airlock, but they'd have to get around the s-curve, so it's unlikely that there was any significant contamination.

A lot of traditional breweries ferment in open containers, and still manage to make excellent beer. Google "open fermentation" and take a look a the images.


@derek.cormier and @bughunter are generally correct. You have a very good chance of everything being fine. Besides oxidation though, you also should consider possible infection of the brew by unwanted wild yeast or bacteria. A lot depends on how fast your ferment got started, and the presence of fruit flies and the like which spread wild yeast from rotting fruit in the area.

If your ferment got off to a good start, then the intended yeast will have bred up quickly, so as well as helping avoid oxidation, you'll be less vulnerable to wild yeast and bacteria infecting your brew.

It's probably a good idea to drop a crushed campden tablet into your brew. Commercial yeast is bred to survive the sulphur dioxide that this releases into your brew, while it will kill most wild yeast and bacteria. The SO2 bubbles off so will have little effect on the final brew, although there are a few people out there who react badly to it even in very small quantities (they know who they are, and have problems with almost all commercially produced wine).

  • After seven days of fermentation, there's nothing left for the yeast to consume. Adding sulphite to knock back wild yeast activity will have no effect, because the yeast are finished. Oct 4, 2014 at 15:57
  • Seems reasonable. My brewing is mostly not beer, and I measure fermentation times in weeks and months.
    – mc0e
    Oct 4, 2014 at 21:25
  • What if the infection is bacterial?
    – mc0e
    Oct 4, 2014 at 21:53

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