Blow off tube..or blow off tube, then airlock?

This is my first time using a blow off tube; as well as a yeast starter and aeration (hence the need for the blow off tube!).

After the about 15 hours the airlock had foam and “stuff” coming out the top, so I replaced it with a blow off tube. Man did it bubble like crazy!

Now (about 40 hours after pitching) the bubbling has slowed significantly.

Should I put the airlock back on? Or just leave the tube in until I rack to secondary (or bottle)? I know that theoretically there is a risk of contamination for the few seconds it takes to yank out the tube and put the airlock in.

Thanks in advance!

No chance of infection exchanging the blowoff for an airlock - there will be a plenty of positive pressure from the CO2 in the fermenter to keep anything from falling into the beer. But you can leave the blowoff in place until fermentation is complete, won’t hurt anything.

The main reasons I replace with an airlock is to use on another beer, and they’re easier to clean when they (blow-off tubes) haven’t sat for a few weeks. A blow-off tube is an airlock. :cheers: