Water Bath temp vs. Wort Temp

I have trouble getting my wort down to pitching temperature lower that the high 70's even when pre-chilling my wort chiller with another wort chiller in an ice bath. I thought no big deal as I always keep my water bath temps at about 65.

However, the other day I filled an extra keg with sanitizer and dropped it into the water bath cooler where I keep my other two plastic fermenting buckets. The temp of the sanitizer was 80*. So I though after a day or two it would be near the temp of the water bath (65*). But the sanitizer temp has gotten no lower that 78*.

Could my wort in the plastic buckets also still be this high? If so, my beer has had terrible temperature control during fermentation. Most likely around 75*. I would of thought the metal on the keg to be a better conductor of temperature but maybe I've been going about this the wrong way.

I'm in Florida so I understand your pain with not being able to cool very effectively using tap water through an immersion chiller... I too tried the pre-chiller in ice method to no avail... I've had much greater success using a pond-pump to recirculate ice water through the chiller. You can get one for around $50 at HD or Lowes. I use regular tap water until it drops to around 100 then switch over to the pond pump... With this method I was able to get down to about 65F in around 40 minutes when I brewed last weekend.

As far as the main question of your post, I too find it hard to believe that your keg of sanitizer didn't equilibrate with cooler water. I have no logical explanation for that one.

That's a great idea, I have a pump recirculating water from my kegorator though my wort chiller (which is placed in my water bath). So I could easily use that same idea to pump cold water though my wort chiller near the end.

I think it would depend on what material your fermentor is made of, as well as the thickness. It would seem to me that a plastic bucket would have some insulating properties compared to stainless steel. That is another reason I ferment in Sanke's. I know that the water bath temp will match the wort temp so I just have to make sure the water bath is at the desired temp.

What I did for my last 2 brews was use my wort chiller and got it down as cool as I could, usually takes 15-20 mins then transfer to my bucket and put in my kegerator until it gets down to pitching temp