Question about yarn dyeing

[astroflammante.livejournal.com]

I am thinking about trying to dye some yarn I was given recently. It's 100% wool, and so I want to try using KoolAid, or rather closest I can get since they don't sell it here. So, since I can't be sure the dye is acidic, I will add some vinegar just to be sure it sets. But do you think I can use "apple cider vinegar" or does it have to be regular vinegar? I'm asking since I'm short on cash and "inherited" a bottle of this when my flatmate moved out. If it can be used, this will be an inexpensive experiment...

Thanks in advance for any help!

Crossposted to knitting