Lambic style in a barrel. Airlock taking oxygen in.

[bbarclay]

Has anyone had an issue where oxygen is being taken into a barrel via the airlock, rather than spitting CO2 out? Backstory: I had a 5 gallon barrel filled with a 65% Belgian Two Row 35% Torrified wheat mash/wort that, last fall (35° night), I put in the window overnight and got some really great spontaneous fermentation. Fast forward 7-8 months. About 2 gallons of beer has evaporated so I brewed an identical batch of wort, chilled it, then topped up the barrel - sort of solera style. I figured I would have some fermentation started by now (topped up on Saturday). Instead, I have the airlock taking oxygen in. Temperature in the house is roughly 69° and the liquid in the barrel is 68.5°.

 

[dantheman13]

Suck back due to a vacuum, caused by slight temperature changes. It's more common than people realize.

https://www.youtube.com/watch?annot...=iv&src_vid=boLqmFIzUZ0&v=aSgp0E96HCU#t=1m45s

 

[bbarclay]

Thanks! I did take a temp reading and the liquid in the barrel was 1.5° cooler. I put a heating pad on the barrel for a couple hours and the the levels started equalize.