Fermenter for aging/conditioning on oak chips

[nakeda]

For this year's Russian Imperial Stout I'm keen to have a go at ageing on whisky and rum oak chips. I would be looking to do a 15L batch split 3 ways - 5L on whisky chips, 5L on rum chips, and 5L without any chips. The one without any chips I'll just bottle directly and bottle age, but for the others I would like to age in a vessel and draw off a sample now and then to check the progress, so I can decide when to bottle. (I realise 5L is quite small, but with 3 of them at 10% abv it's enough for me So I think to do this I need vessels that:

1. Have low oxygen permeation.
2. Minimal headspace on a 5L batch (again to avoid oxygenation).
3. Allow a sample to be drawn off without introducing oxygen.

Basically I think I need small vessels made of PET or glass, with a tap. Any recommendations/suggestions?

[jaroporter]

got mine in polypins. they collapse to push out all the air and have a tap. i've read that they can keep beer fine for a year or so, but mine's not got there yet. i've not used woodchips, how long do you think it'll be before bottling?

[nakeda]

Thanks, hadn't considered polypins and I haven't used them before. Are they really good for long term ageing? From various sources the ageing time for oak cubes would be minimum of 4-5 months, possibly 12 months+ depending on how the flavour develops. One recommendation I just read was to use small glass demijohns and a wine thief to take samples - apparently should cause minimal disturbance if not taken too often.