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When to use a blowoff tube

Sunday, September 21st, 2008

For dark beers or beers with a specific gravity greater than 1.060, in my experience, a blow off tube is need to keep from having an overflowing mess.

Here is a picture of a porter that is only 24 hours into fermentation. You can see the amount of gunk on the glass in the head space got up to the airlock. I pitched two cups of slurry from a previous batch of English Pub Bitter and the fermentation took off like a rocket. In five hours the tube was making a tapping noise every couple seconds as it bubbled. The strain is White Labs British Ale Yeast.

Blowoff tube

  1. 2 Responses to “When to use a blowoff tube”

  2. I am planning on brewing the Brewhouse Stout kit. This is going to be my first home brew batch. Do you think I should use a blow off tube? The specific gravity per the site is 1.044. I have heard from a friend that the airlock will not be sufficient for the amount of gas.


    By the way, I love the site – it is very useful!

    By Graham on Oct 25, 2010

  3. Hi Graham,
    Welcome to the fold! Yes, get a blowoff tube to be safe. That’s not a very high SG, but for a dark beer, I usually get enough head in a five gallon batch to make it to the spout of a 7 gallon carboy.

    Have fun, and don’t forget to keep good records. Check out the brew day sheets.

    By Larry on Oct 25, 2010

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