Airlock blowout !!!

This is the story of beer coming out of my airlock.
For most batches I use water container as a fermenter. 
But for this precious batch of IPA, I chose to use the carboy.
I didn't want to risk any infection on this batch.
I also wanted it to look cool and see the airlock bubbling, so I stuck in an airlock on the carboy too.
Now I come back from office the next day and open the fridge to see check on the beer.

The beer had come out of the airlock and was all over my carboy.
A picture will show how bad it was.

The airlock is full of krausen. I am still struggling to clean it.
I was cursing myself for using the airlock :(

Blow Off Tube - 

I quickly cleaned up the beer on the outside of the carboy and the lid with Sanitizer, and stuck a blow off tube into the hole in the lid.


How to fit a blowoff tube - 
  1. Take a silicon tube or any other soft pipe.
  2. Drill a hole in the lid of the carboy. The hole should be smaller than the outer diameter of the tube.
  3. Sanitize the tube with some sanitizer. Inside and outside.
  4. Push one end of the tube in the hole in the carboy lid. Since the hole is smaller than the tube, the tube should fit snug and tight. So there is no air leak.
  5. Now take a glass of sanitizer and keep the other end of the tube in the glass.
TIP : Pointed out by a fellow homebrewer - Use a thick pipe, so its easier to clean. The pipe I have used will be as difficult to clean as the airlock.

You will see the bubbles coming out in the glass.
The video below will show you that.

Conclusion - 

Always use a blowoff tube instead of an airlock.

Advantages of the blow off tube - 

  1. Easy to make, airlocks cannot be bought easily in India.
  2. If there is a small blowoff, it will stay in the Sanitizer and the container.
  3. Tubes are easy to clean as compared to the Airlock. ( Only if the tube is thick enough )
  4. Airlock takes a lot more space on the top in a fridge as compared to the blow off tube.
Please post your comments to let me know what you think.


  1. Hi Sapan! I did my piece of research on this topic and my suggestion is that you should try using the 3-piece airlock. The S-shaped ones are ridiculously hard to clean. And yes, when krausen enters the blow off tubes, they are equally hard to clean. I have had to throw out 3-4 tubes since you JUST CAN'T REACH the middle section of the tube where the krausen is stuck. The 3-piece airlock can be completely dismantled. I faced the exact problem during my last batch of IPA (the one where I used T-58). I removed the airlock, cleaned it off yeast, sanitized it and put it back on the fermenter in under 5 minutes. Of course, to each his own, but my suggestion would be to get a 3-piece airlock.

  2. Hey Partha,

    I agree with you on the 3 piece airlock being better than the S-shaped one.
    But even with that we will have beer all over the carboy which is a mess to clean.

    Also the blow off tube that I used is very small, and as you say it could get clogged.
    I think a better solution would be to use a thick blowoff tube. Like 2 cm diameter, so its easy to clean.

    John Palmer suggest using a 1 inch diameter hose -

    1. Yeah I agree. I'm not saying the 3-piece airlock prevents krausen :P. It still would create a mess while the blow off tube won't because it simply would 'siphon' the krausen into the container. A thicker blow off tube would work best, yeah. I read that high gravity beers will form more krausen. So whenever I'm gonna make a high gravity one, I'm gonna use blow off tubes. Otherwise the airlock :)

  3. Hey Sapan, Interesting fermenter there! Do you know any place where i can buy this, online or in bangalore?

    1. Its a Polylab branded 10 liters aspirator bottle.
      So if you can find a Polylab / Tarson dealer in Bangalore, he can supply it.

      Otherwise just get it online at -

      Tolexo service is very poor, but they eventually deliver.
      They also have other options. Search for "carboy" or "aspirator"


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