Until this past weekend, I’ve never harvested yeast as it’s just not a part of brewing that interests me enough to alot the time, equipment or cooling/storage. This past weekend I pitched a Wyeast 1272 that I had created from a snack pack the week before, but we ended up not brewing that weekend.
I initially used the yeast starter calculator on this site as it always produced good results for me, and probably would have done the same had I brewed last weekend. Fast forward one week... the yeast was now a week old and per the calculator on this site, was now a bit short on yeast count due to a week’s yeast loss. (The first yeast starter was barely over what the calculator called for). I re ran the numbers in the calculator and found that I needed a 0.1 quart yeast starter. With it only being slightly under the pitch volume for yeast, I went ahead and pitched it and it is fermenting away now.
I say all of this as there looks like a lot of potential variability that could effect your results. The jars appear to have way more yeast than you need, even though they are a month old. You don’t want to dramatically under under or over pitch your yeast as it can bring on less than desirable outcomes (I’ve only read this as I have not over/under pitched in dramatic fashion (yet)). So unless you can determine within reason, how much yeast you have, I would get a fresh yeast (dry or liquid). But this is my opinion, and remember, I don’t harvest yeast. Nevertheless, no point in ruining a good wort and brewday with a bad yeast decision.