Vacuum pressure in an airlock????

[pightr]

I am in the process of clearing my kit wine right now and was just checking on it the other day and it had pulled a vacuum through the airlock. Not sure how this happened but instead of having pressure pushing up on the airlock to almost bubble its the complete opposite of what it usually is. Wish I had a photo for you guys but as of right now I do not. I went to check it again tonight and it again has another vacuum pressure even after I released it last time.

My kit is a Island mist strawberry white merlot. It is in its fourth week of clearing as of right now. I just racked for the first time from the secondary to get it off all of the lees. Not sure as to how this possible could work but ya im at a loss here.

 

[buddy]

I see that as well with my carboys. It could very well be due to a change of temperature in your house. When the house is warm the wine will expand in volume, if the house becomes cooler by even a few degrees the wine will also cool. When it does it has less volume and that is how you end up with negative pressure in your airlock.
When the wine is actively fermenting you will not see this because the CO2 is constantly producing a positive pressure on your airlock.

 

[RedNeckWino]

Sounds like room temp may have came down. Like a soda bottle with the lid on in the car, collapses bottle when it cools off out side.