3 piece fermentation lock

[Hose]

Today is my first brew. All seems to have gone well....so far. One simple question. I'm using a 3 piece fermentation lock. This will sound stupid but here goes, after filling 1/2 with water, then putting the small cup (upside down) in the lock, do I put the top cap on or leave it off?
Thanks

 

[downinit]

Put it on.

 

[earwig]

Put the airlock on, put in the middle cap, fill it and lastly put the top cap on.

 

[Hose]

Thanks !

 

[BeerBDrew]

I would say no. The water (or other liquid) in the airlock allows gases (Co2, sulfer, etc) to escape the container, but traps airborne contaminants, thereby creating a safe harbor for your beer. The lid is extraneous and is probably intended to give you the warm fuzzies, but does nothing that the water can't do 1000X better.


*edit* That said, I put the lid on when I use a 3-piece, and I prefer a 3-piece because of the glorious airlock sniffing opportunities it affords.

 

[TheBroonery]

I use grain alcohol in my airlocks. I know it's overkill but nothing harmful can grow in it.

 

[devilishprune]

Star-san (or another no-rinse) works too, and you probably have that sitting around. I put the lid on because: why not? It helps keep big bugs out of your water and it doesn't hurt anything.

 

[SumnerH]

Star-san (or another no-rinse) works too, and you probably have that sitting around. I put the lid on because: why not? It helps keep big bugs out of your water and it doesn't hurt anything.

+1 on this. Star-san works well, and for long-aging beers it doesn't evaporate nearly as quickly as vodka/grain alcohol.