FWIW, those soft sided coolers never really worked for me, I think the zippers just couldn't get a good enough seal. I used one of those cheap styrofoam cooler that they ship frozen things in. The styrofoam was about 2" thick and it had a tight fitting lid. It seemed to insulate better than any other cooler I've ever used, plus it was free.
I concur. My softsided coolers don't help much at all. The hard-sided plastic cooler is a little better but the best cooler I've used was a disposable styrofoam job with tight fitting lid. Only lasted 15 years though. :-)