Questions about hard cider production (off smell and color)

Hi,

My cider just spent about 3 weeks fermenting and now it smells bad and looks very yellow... How do I get both this smell and color to dissipate?

Before fermenting the must/juice I treated it with Potassium Metabisulfite (at the dosage recommended on the package). Could this have caused the smell? I also used a dry wine yeast.

I thought maybe something else was causing the smell so I added some more metabisulfite to the now fermented cider to cease any active processes and racked it into an oak barrel.

Should I put in the wooden bung or should I put in the airlock to let the smelly gases escape? How long should I let it age out these undesirable traits?

Thanks for any advice/input!!

One characteristic of cider fermentation is SO2 being given off. Smells like farts. It is OK, and the cider will be fine.

Not sure what the added metabisulfite has done. Put an airlock on it. If it is still active, you need to somehow let the air escape.