Tannins?

I did a 10lb pale 1lb cara-pils brew today, my mash temp was a bit high 71C but i figured it wasnt the end of the world so i left it. My efficiencies have been kinda low 60% ish, i know my crusher is mostly to blame but i tried a couple new things with my mash. I fly sparged as usual till i collected 3 gallons, gave it a vigorous stir and recirculated thoroughly then proceeded to collect the rest.

Another thing is i left my burner on while sparging because i always dip into the 55-60 range on my MT with my sparge water at 80 or so i figured id give it a little boost in heat to help disolve some more sugars, held 70 on the mt this time.

So the problem is after my regular boil shedule i tasted it and it had the most horrible puckery taste, which i assume to be extracted tannins, but im not sure on that one. It could also be the cara-pils im using, it is ridiculously hard to chew on and not particularly sweet like every other specialty malt iv tasted.

So im sure if the grain is to blame or my slightly hotter than usual mash.

I have not noticed that the times that I have mashed with CaraPils in the mix.

Probably not the carapils fault. 71C is too high, you know that now. Standard advice is to raise the mash to about 78C when sparging, but it doesn't sound like you did that.

The pH of the wort may have been the problem which saw excessive leaching of the tannins. Suggest you read up on sparge volumes and pH readings and see if anything in there rings true to your effort.