Cider/Wine airlock bubbling backwards

[Accidic]

This post may better fit in the yeast forum but for now this one seems the best fit.

Given a limited crop of muscadines (that I didn't have to brawl with bees for anyway) and a really really old asian/english pear hybrid I decided what the hell and made a pear cider supplemented with muscadines and sugar.

After a couple days of billowing clouds of pulp it apparently didn't appreciate and a few more days of bubbling it has had an identity crisis and now is bubbling backwards into the sealed fermentation vessel. Has anyone seen anything like that (or alternatively are my search skills that pathetic?)?

I don't worry about lack of airlock activity typically and the smell when it was very pleasant so the wife will likely not give me grief even leaving it for as long as it takes but should I be concerned about reverse airlock activity?

Am using Lalvin 71B-1122 and pectic enzyme as well if it matters.

 

[krisabsinthe]

If your airlock is working in reverse there are only two ways this could happen
1) your must was above the current temp when you fit the airlock and science has taken hold creating a "vacuum effect" in the same way we can fruits and veggies.
2) the atmospheric pressure has increased since you fitted the airlock and air is being forced into the carboy as the pressure is less inside.

With that being said reverse airlock activity is pretty rare and fairly short lived when it does occur. Also I would like to say that if your using the "S trap" type airlock change it to the 3 piece guy, they are easier to wash and I think function better. Also if your airlock is working in reverse you should have had to refil it several times, either that or the laws of physics have begun to break down, which knowing how some of us HB guys are is not totally impossible

Edit : the solution to either one is to remove the airlock and replace it

 

[Insomniac]

Why would you have to replace the liquid in an s type airlock? It bubbles just as well in both directions...

 

[Accidic]

Thanks. Not sure why the temp inside would have changed as the outside bottle temp shows the same but that has to be it I guess. The only thing I could think of was the pear pulp breaking down was compressing it's size slightly creating a vacuum but even that seemed a bit unlikely.

Edit: Oh, and I'm out of 3 piece airlocks atm (multiple other batches using them) and was down to s-type for this batch. Will post a pic or two depending on whether they're too big for hbt or not. Can't remember the size restrictions... Just please excuse the mess as we're changing around one of the rooms for the newborn and the kitchen has become a temporary landing zone.

 

[Accidic]

The batch from a couple days ago starting to eat the initially rejected pear pulp...

(Will video the reverse airlock thing and post if it's not too big.)

 

[superslomo]

with a 3-piece, you can have the liquid in the airlock pulled into the chamber (not good, unless you are using starsan or something similar).

 

[krisabsinthe]

Why would you have to replace the liquid in an s type airlock? It bubbles just as well in both directions...

I was my aware they worked in reverse without pulling liquid in, interesting