Starsan in double bubble airlock keeps getting sucked into fermenter - why and how to prevent?

Question

Starsan in double bubble airlock keeps getting sucked into fermenter - why and how to prevent?

Rich Prag

2019年4月8日 07:39

I did a brew on Saturday and cooled, got in the fermenting bucket and added yeast, added starsan to the chamber in the double bubble airlock and got it under the stairs. Ever since then, the starsan gets sucked into the fermenter, fairly quickly as well (after I replace it). I've heard this is due to temperature change creating a vacuum. I've also heard that that shouldn't happen with this type of airlock. Its not happened before to this extent (i.e. I've never had to replace the starsan).

Any ideas why this is happening? And is there a way I can prevent it? I'm not too concerned right now as the yeast is still working and producing carbon dioxide but when it finishes I still plan to leave it (three weeks in total) so I don't want the possibility of oxygen getting in.

Topic airlock techniques yeast fermentation beer homebrew

Category Mac

user7268 · Accepted Answer · 2017年11月15日 11:46

1

user7268 answered at 2017年11月15日 11:46

I use vodka in my airlocks, you know, just in case it gets sucked in.

Jeff Roe · Accepted Answer · 2017年11月15日 03:36

You're putting too much liquid in the bubbles of the airlock. If each side is only filled about one-third, none of the liquid will either be sucked out or blown out.

The fluid in a properly-filled airlock will not get sucked out. As you can see in the picture of the properly-filled airlock below, there is not enough fluid to overflow the bubble chambers in either direction.

Also, as barking pete has answered, you might as well just fill the airlock with water.

EDIT:

In the comments below Wyrmwood says:

The pressure in a fermentation chamber with a good seal after moving from ale temps to a fridge to cold crash is plenty to empty a standard airlock or to suck a half-filled quart jar dry with a blow off tube.

My reply is that sure, it could suck fluid out of a blow-off container through a blow-off tube, but no, it won't suck the fluid out of properly-filled airlock such as the one pictured here. It will suck air through the fluid, but the fluid will be left behind.

barking.pete · Accepted Answer · 2017年11月1日 13:59

1

barking.pete answered at 2017年11月1日 13:59

One sensible suggestion is don't put starsan in the bubble trap - just put water in there. There is no need to use an antiseptic in the air lock.

Evil Zymurgist · Accepted Answer · 2017年10月24日 12:23

This is caused by a drop in temp before co2 is being produced. Just cap the fermenter in sanitized foil until you're past the lag phase, or cooled to fermentaion temp. Though a little bit of starsan won't hurt much, foil is better than an open airlock IMO.

I don't put air locks on until the wort is at fermentaion temp. I also remove the airlock then foil cap when cold crashing to prevent the same issue.

Starsan in double bubble airlock keeps getting sucked into fermenter - why and how to prevent?

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