RIS Extract

I recently brewed a 13.5 gal batch of extract RIS (Home Brew Club Style for AHA). I think I may have pitched to much yeast. My air-lock blew off my fermenter. Luckily I saw the cap bulging and I a blow off tube sanitized and ready. My temp didn't get to high, I didn't smell any esters coming off the blow off tube. Will over-pitching effect my beer?

I doubt that you pitched too much yeast for an RIS. That would require a very large starter done on a stir plate or several packs of dry yeast. Your RIS has a lot of fermentable sugars and the yeast just went nuts over it. Unless you had it in a fermentation chamber with temperature controller there is a good chance that the activity of the yeast raised the temperature of the beer by several degrees too which adds to the speed that the yeast consume the sugars.

Don't worry about it. Just remember with big beers you need to set up a blow off tube for increased pressure and high krausen. I've never had high krausen blowing out my tube but many others have. Colder temps will help, my Imperial Stout I just made just before the new year was fermenting around 50 degrees in my apt, but the fermentation brought it up to 62-64 degrees I think. It heats up big time.
13+ gallons sounds like its going to be a great fall and winter! Thats a lot of RIS!