Lengthy tertiary fermentation

[WelshPaul]

I'm planning on making a beer soon that calls for a tertiary fermentation period of 3 months. Can the beer be left in a normal FV with an airlock in place for this long or would a glass carboy be better?
If it is going to be a carboy approach, should the beer be sealed with a stopper once airlock activity has ceased in order to protect the beer or will the layer of CO2 on top do this for the 3 month period?

 

[rpt]

I'd want to do this in a sealed glass or stainless steel container with airlock. It sounds like a long time to leave beer in plastic or without a secure seal. But I have no experience to support this.

 

[Asalpaws]

Apparently glass is much better than plastic buckets at keeping out oxygen. I would use an airlock though, avoids risk of carbonating the beer early or the whole thing blowing up!

You could always throw some sugar in the beer after racking into glass. The small amount of fermentation should purge the head space. T