Mash temp too high - help!

Somehow when I wasn't looking my mash temp jumped from 155 up to about 175. It was probably at this temp for no more than 10 mins near the start of the mash. I quickly turned off the heat and added a little room temperature water to bring it back down under 160.

Will this be a problem for starch conversion, or should I be ok now that I corrected? Is there anything I can do to make up for it, like extending mash time by an extra 10-15 minutes overall?

Thanks!

Do an iodine test to see if you have conversion.

Well my OG was right around where it should be, so hopefully that's a good sign. Maybe I had enough starch conversion before this happened.

What do folks generally do if they denature / destroy a major chunk of their enzymes if the temp creeps too high? If you hit say 162, all the beta amylase should be mostly destroyed, right? Can you mash for an extra hour or so to try and knock the remaining starch down, or does that run the risk of pulling out tannins?