Is it normal for secondary to have negative pressure?

I have a high gravity Bock that clocks in at about 9.5% ABV.

I left this one in primary for 3 weeks and then moved it to secondary to condition for a couple of months.

Now, after 2 weeks in secondary it has lost positive pressure and is sucking air back in.

Is this normal?

Are you sure you are getting suck-back and not evaporation?

If you are getting suck-back, it's probably due to a temperature change.

Here is what I am going by...

This secondary is sitting right next to the negative pressure secondary.

I just moved it to secondary yesterday. It still has a positive pressure bubble every once and a while.


This is the negative pressure secondary, which sucked a negative bubble back right after taking this.


Like I said, they are all sitting together.

Looks like the temp is probably falling and the wort/beer is cooling from the fermentation stage. So the liquid volume and CO2 volume is decresing with the temp reduction.

FxdGrMind said:

Looks like the temp is probably falling and the wort/beer is cooling from the fermentation stage. So the liquid volume and CO2 volume is decresing with the temp reduction.

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Yep, exactly what I was thinking. You were just a little more articulate than I was.

In short, impatient (you are certainly living up to that name! ), there's nothing amiss here. You may want to fill that airlock with cheap vodka, especially since you are leaving it for several months.

I think I know the answer to this q, but why the cheap Vodka?

Cheap vodka will remain antiseptic enough to help make sure your secondary stays sanitary if any gets sucked in. Bourbon works too.

FWIW, I've had many airlocks go dry during extended aging, with no problems.

Vodka won't let any nasties grow in it, plus if you get enough suckback that the liquid gets into the beer, you've just upped your ABV with zero chance of contamination. water won't do that for yah.

flyangler18 said:

You may want to fill that airlock with cheap vodka, especially since you are leaving it for several months.

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It is suppose to be my day off, but, I had to run off to work and reboot a server.

I have StarSan solution in the airlock. That should be good right.

impatient said:

I have StarSan solution in the airlock. That should be good right.

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Should be fine! I'd still recommend cheap vodka for really lengthy secondaries. As an example, I have a Berliner Weisse that'll likely be in secondary for another 3 months.

As long as the airlock is not filled past the lines you can't get any liquid suckback, just an air bubble or two maybe.

ifishsum said:

As long as the airlock is not filled past the lines you can't get any liquid suckback, just an air bubble or two maybe.

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I've gotten suck back when the al is filled below the line several times. I think the line is more for the inner part hitting the lid.

strider said:

I've gotten suck back when the al is filled below the line several times. I think the line is more for the inner part hitting the lid.

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You lost me...

I think he's talking about a 3 piece airlock...and yes I have too on those types. I was speaking to the S-shaped one that Impatient is using.