Do I need to restart an "old" yeast starter?

Tried to get some brewing done these past two weeks but either the excessive heat or other issues have put off my brew days. Thus, I have been building yeast starters in the anticpation of brewing only to have my brew day postponed. I have then placed the starters in the fridge and would like to know should I make a very small starter to help these larger starters "wake up" prior to pitching or just pitch the 1-2 week old starter yeast?

I've pitched starters that'd sat in the fridge for a ~week or so without any issues. You could always decant the starter and add fresh wort to be sure, but I'd say you're fine pitching the starter you have.

Looking closer at my stock I have a few jars of starter that have been decanted, store in a jar and refrigerated for 3 weeks now. I was thinking of just using 500 ml of fresh wort to help wake these starters up the night prior to pitching.

Thanks for your reply.

That'd work too. Refrigerated yeast has a decent shelf life, IME. Whenever I'm in doubt about it's viability, I make a starter, but a week or two shouldn't affect viability too much.

You could always run a Mr Malty check on it. I think refrigerated slurry is still at least like 85% viable after a week so I honestly can't see you having problems with it if you pitch it in the next few days.