Ok, so as it turns out, something came up and I wasn't able to brew at the weekend. I will not be able to brew for another two weeks and I've already activated my 2 smack packs (they are currently in the fridge. One swollen, one not). My stir plate situation will be up and running again before my next brew day. Can I still use these two smack packs to make my starter then or do I need to buy some fresh yeast?