Stuck/Slow Fermentation query

[Dr Horrible]

Hi All,
Not a big cider expert (only done one previous batch) so looking for some advice.  My sister asked me to provide some brews for her wedding this summer so cider was definitely one for the list. However, I'm a bit wary of providing a standard strength 6% cider for an average wedding crew and all my sisters are big fans of Stonewells Tobairin so my intention was to ferment out the cider, add some metabisulphite/Campden tablets to deactivate the yeast, and then dilute the batch back to 3-4% with apple juice.
So, kicked off the batch - used 20L of Bramley/Liberty blend from Geterbrewed (great value in fairness for a lovely juice and a very handy 5gallon container!), boiled a few teabags and raisins together with some yeast nutrient, hydrated some Nottingham yeast(had used a cider yeast previously but a few guys I'd talked to had used Notty so decided to give it a shot) and added it them all in together.  Fermented at a temp of 18degC and the batch bubbled away, and gradually increased the fermentation temp to 22deg C over the course of the fermentation.  Two weeks later, the krausen had dropped and I thought the batch was done.  Measured the FG and it was 1.020 (OG was 1.046).  Five days later I've measured it again and it hasn't moved.  So I'm looking at a 3.5% cider which doesn't seem to be moving anywhere.  Seeing as this is pretty much exactly where I wanted to be in the first place I am very tempted to keg up the batch (using minikegs for ease of use and transportation purposes) and call it quits but I wanted to check with some more knowledgeable people here - if I keg up the batch as is and leave it sit for a few months (until August) will it slowly continue to ferment?  I'm not intending to prime this, I think still cider will be fine, but I'm a bit worried about too much CO2 generation over a long period of time.  I am thinking of adding Campden tablets before I keg off to be sure but will this stop any beneficial flavour development as well?  How much adding Campden tablets affect the taste? And any ideas as to why the batch didn't finish out?

[Will_D]

Re. the slowly fermentingness: Yes it probably will continue to referment particularly if it warms up to 22 to 25C (ie Summer!). It will probably be a malo-lactic fermentation which is great for an over acid cider but if yours tastes just right the you don't want it.

Rather than add sulphite (which can give drinkers headaches) why not pasteurise it?

Dead simple: Heat to 65C (or 70C to be sure) Hold at temp for 15 mins and then cool quickly (imersion chiller or pate)) if possible and keg it.

If not possible to cool quickly then let cool on stove with lid on till about 40C then keg it.

Previously flush the keg with CO2.

Add CO2 to prevent keg imploding as the air inside cools down.

[Dr Horrible]

Thanks for that, I was a bit worried about adding the sulphites, I'll give the pasteurising a shot instead. 
Cheers!

[Will_D]

Thanks for that, I was a bit worried about adding the sulphites, I'll give the pasteurising a shot instead. 
Cheers!

Excellent descision!

When Ciderhead and myself first pasturised cider we were both amazed to find:

1. It didn't end up tasting like stewed apples
2. Any hints of H2S (Hydrogen Sulphide) were removed
3. Any haze tended to drop out when chilled
4. It "rounded" the flavour nicely

And the beauty is you can then add any natural (pasturised) sweetners:

Berries/AJ/Honey/Herbs

ANd the guests won't get funny flavours/feelings/stomachs from the artificial sweetners/preservers (sulphites/sorbates)

[Dr Horrible]

That's very interesting information on the pasteurising, I didn't know that at all. Garry also mentioned last night that he'd pasteurised a batch before so it definitely looks like the way to go. I'm very tempted by your idea of using berries or herbs for sweetening but I reckon I'd better keep it simple for the wedding.  However I think I'll try replicating this batch again for myself to see if I can get the same thing to happen (Id prefer a 3-4percent cider to a 6percent) and then I could try a couple of different things in different mini kegs- now I have them, I might also well put them to use.