Grain steeped to hot?

I just cracked open a bottle of porter that is about 2 weeks in the bottle. The flavor is progressing nicely. It's malty sweet with a pronounced bitterness. Much improved over last week's sample!

The recipe I used called for 1 lb of crystal (I used 80L) and 1/4 lb each of black patent malt and roasted barley to be steeped at 150-160 deg for 30 min. The temperature shot up to 175, it was between 160-175 for about 3 minutes. I got the temps down pretty quickly.

I know that overheating grains can cause off flavors. One website said that this can cause astringency, something I can't detect in this batch. Although I try to be very careful to hold steeping temps, is this less of a problem with extract brewers who steep fairly small quantities of grain than with partial mash and AG? I'm figuring I would have tasted a problem by now...

I've hear alot of people talk about steeping and putting the bag in and taking it out when it reaches a boil... I do what the LHBS told me which is to get the water boiling then cut the heat and move the pot off the heat and steep for 3 minutes... He's experienced so i trusted him...

i would say all the kits and recipes i would get the water up to 150 or 155 turn off the heat and then seep my grains. i also have a thermomitor handy so i can watch the temp. i know some kits call for a temp to he held while seeping the grains. and yes the temp is a factor becuase you are extracting enzymes and other yummy products from the grains

I doubt you harmed your brew much. There aren't many fermentables to be gained from properly mashing the grains you used, so overshooting the temperature won't be too detrimental in terms of enzyme action. Temps above 180 are where you'll begin to see tannin extraction and astringency. I think your beer will be just fine. RDWHAHB!

Astringency is one of the off-flavors that is easily avoided. I've never gotten it with steeping specialty grains. I've had it by fly sparging at too high a temperature without buffering the sparge water. But, pH 5.2 and batch sparging solved that.