# Vacuum?



## BeeCurious (Aug 7, 2007)

Since there isn't any fermentation your airlock is simply reacting to the volume changing because of temperature fluctuations. IMO


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## Ben Brewcat (Oct 27, 2004)

Beecurious is right on.... temperature (and resultant volume) changes, barometric pressure, etc. This is one reason S-type airlocks are more popular than 3-piece.


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## BeeCurious (Aug 7, 2007)

Ben Brewcat said:


> Beecurious is right on.... temperature (and resultant volume) changes, barometric pressure, etc. This is one reason S-type airlocks are more popular than 3-piece.


Won't the S-tube suck the airlock liquid back into the carboy?

I don't see how the one would be prefered.


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## Gibbus (Apr 22, 2009)

Ahhhh.....basic physics to the rescue. 
Nice to know the last 5 months haven't been in vain.
Thanks guys!


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## Ben Brewcat (Oct 27, 2004)

BeeCurious said:


> Won't the S-tube suck the airlock liquid back into the carboy?
> 
> I don't see how the one would be prefered.


Apply pressure in each direction to it and it'll be clear. The S-style, or double-bubble, bubbles in either direction as the gas passes through the narrow and into the reservoir on each side. The three-piece (stem, cap and lid) is the one that can suck liquid back into the carboy.


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## BeeCurious (Aug 7, 2007)

My work takes me away for weeks at a time so I can't baby-sit airlocks. My three piece airlocks have a line molded into them that I mistakenly assumed was intended to indicate a "full mark". 

If filled to that level there is enough liquid in the airlock that some can be sucked into the carboy.

To avoid that, I fill the 3-piece airlocks to about 3/8" below the misleading line.

One could always over fill the 3-piece airlock with their favorite booze and then "adjust" the level...


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## Gibbus (Apr 22, 2009)

> The S-style, or double-bubble, bubbles in either direction as the gas passes through the narrow and into the reservoir on each side.


So if it (and it's almost ready to) bubbles in the opposite direction, toward the carboy, would that air "contaminate" the mead? Is this I sign I should bottle ASAP?


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## BeeCurious (Aug 7, 2007)

I am new to cider and cyser making...

What is the gravity?

It seems that it may be finished.


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## Ben Brewcat (Oct 27, 2004)

Gibbus said:


> So if it (and it's almost ready to) bubbles in the opposite direction, toward the carboy, would that air "contaminate" the mead? Is this I sign I should bottle ASAP?


Not very likely. The main worries are fruit flies, dust, etc, which would get hung up in the water. That said, using cheap vodka (or in my case, dilute Star San) will sanitize anything coming through and won't harm the bev if anything drips in.


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## Nabber86 (Apr 15, 2009)

In my ealy days of brewing, I used a blow-off tube with the end of the tube submerged in jug of water. One time I put a good splash of bleach in the jug with the water because I was expecting a lot of trub from a very heavy batch of beer and the blow-off water tends to get messy and gross after a while. The wort was also a tad bit warm when I pitched the yeast (~80 F), so I put he whole assembly in the fridge overnight to let it cool. I am sure many experienced brewers that are reading this are chuckling right about now. (For the uninitiated, when I opened the fridge the next day, all of the bleach water had mysteriously dissapeared).

I still prefer blow-off tubes to airlocks (at least in the primary stage). Only since then, I make sure the volume in the tube is less than the volume of water in the jug.


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## Ben Brewcat (Oct 27, 2004)

Use the one-inch tubing. It fits neatly in the carboy neck, and it has enough volume that if it gets negative pressure it'll burp before it inhales. And it won't plug with blow-off.


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## Nabber86 (Apr 15, 2009)

I was using standard 3/8" ID racking tube. :doh:


Anyway that was some time around 1989. Havent done it since.


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