Blowoff hose to airlock

Hi All,

A quick question. I started a batch on Saturday with an airlock on a 6 gallon carboy. The fermentation was so vigorous that the foam started invading the airlock Sunday evening, so I switched to a blowoff tube, which was still bubbling this morning. My question is, should I switch back to the airlock once the fermentation calms down a little? And if so, when? Too soon, and I'll have to switch back, too late and I guess I could oxidize the beer if it's not producing enough CO2 to force out any air that gets in there during the switch. It would be easier to move with the airlock, though I'm not planning on moving it until bottling day so I guess that's not much of an issue. I'm sure this question has been asked before but I'm not sure how to search past forum posts.

You can leave the blow-off tube on there as long as you want. There is no worry about oxidation because there is still a layer of CO2 covering the beer. It really is your choice if you want to change back to a regualr airlock, but not necessary.

Once the krausen starts to subside, feel free to switch. As the fermentation occurs, CO2 is released which fills the headspace. Once that occurs, you could remove the airlock altogether and leave it off for quite a while with no issue. The CO2 isn't going anywhere very fast. No issue with oxidation if the airlock is off for less than 5 minutes.

That being said, for contamination risks, there is no reason to have the airlock off more than about 30 seconds.

Switch whenever you want. There is little risk.