Grommet vs runner bung

[Newbrewer1]

Hi all
So a made the classic rookie mistake of pushing my airlock down too hard and the grommet fell into the wort!!!
Left it in rather than trying to fish it out. Hopefully will be fine and I’m going to get a replacement lid anyway but made me wonder…..
Why do plastic fermentor use grommets? Is there any reason I cannot expand the hole and use a rubber bung and air lock? I think this would be easier
And my existing hole/grommet is not in the centre of the lid but to the side. Looking online a lot are like this, but why?
Could the hole/airlock not be centre? (This is for a basic 32l plastic bucket)

I know airlock is not essential but I like to watch the bubbles!

Thanks in advance

 

[YeastFace]

A grommet "seals" on both sides of the lid. A bung doesn't and there is potential for it to get ejected by the pressure. Whether that happens under fermentation pressure with an airlock I don't know.

Where are you? I have a few grommets (I think) left over from my plastic bucket days you're welcome to.

 

[Newbrewer1]

I’m in Yorkshire
Thanks
I do have spare grommets
I see what you mean by seal
I guess as it is not a hard plastic lid, as pressure builds it will flex and leak with a rubber bung
Guessing that also why keep the hole off centre, as the centre will have the greatest pressure

 

[MashBag]

I see what you mean by seal

I don't.

The seal is the same else the airlock would not bubble. Sorry confused.

 

[Chippy_Tea]

I used to use 5 litre spring water bottles with a hole drilled in the lid to take a rubber bung and airlock i never had any issues with the bung pushing out but that's probably because the bottle top is much smaller in diameter and a lot stiffer compared to a thin FV lid, i would use another grommet rather than drill the lid.

 

[MashBag]

i would use another grommet rather than drill the lid.

 

[Newbrewer1]

Thanks all
I will get a new lid
But going to stick with a off-centre grommet
Just in future remember to add the airlock to the lid before putting the lid on the fermentor

 

[tondy79]

I have lids with off-centre holes and with central holes, and haven't had a problem with either (though they have plenty of headspace to work with)

I tend to prefer the lids with holes in the centre

 

[tutshiveandspile]

I use this type it holds the shaft of the air lock steady. And is substantial.
Had my two for years. Also the off center hole is best.As the lid is less flexible near the rim.

 

[ricardo]

Twist the airlock back & forth as you insert it or remove it.