when using a 5 gal igloo cooler for the mash tun, Should you stir the mash after first adding the grain? If Yes how often?
Yes. Otherwise you’ll end up with hot spots or dough balls. I add water, grain, stir. Add more water, the rest of the grain, stir. Then I add the remaining water, stir and then take the temperature and adjust accordingly ( hot water if too low, cold water if too high ). I find with my setup ( 70 qt rect. Coleman cooler ) it takes a good 5 minutes or so for the temperature to stabilize.
Yes, definitely stir when you add grain. Keep stirring until you get a consistent temp reading at any location or depth in your cooler. This make take 3-5 minutes. After that, there’s no need to stir further. Just close up the cooler and let it sit until the end of the mash time.
+1
…except that I give the mash a stir halfway through the mash to mitigate any localized gelatinization of sugars. YMMV
I always forget to do this…gotta stop drinking before I brew 
Have you experienced problems by not doing this?
Up to a 5% drop in efficiency.
Not trying to hassle ya, just to get additional info…are you sure it was directly related to not stirring halfway through? Did you do identical repeat batches stirring and not stirring? I’m curious because when I tried stirring halfway through, I didn’t see any differences. I’m just trying to rule out other influences in your case.
No problem Denny…I attribute the small drop in efficiency to stirring as that being the only variable that was changed in back to back batches of an APA recipe I have also found this to be the case on other repeat recipes this year. I am finding that I consistently get in the 75% +/-3% with my current single infusion mash process with APA/IPA range recipes which equates on average to about a 5% increase prior to stirring.
My grain mill is set at .040 (factory setting) and has remained unchanged. My water is Poland Spring water which I believe to be fairly consistent in that it is filtered and tested routinely.
Thanks for the info, Ron.
Your quite welcome.
Mash comes from the german for mix (measc in Irish). At one time, someone stirred the “mash” for the entire 1-2 hour period.
In my experience a thorough mixing at the beginning of the mash works great.
Thanks for the info…I have only been brewing a few months and had some beginners luck on my first brews…My last few have had very little body…I was trying to check what I had done different. Stiring the mash was one thing I did change
Did you start stirring the mash and after that noticed that your beers had less body? If so, did you recheck your mash temp after stirring halfway through? If it dropped significantly due to stirring you might have ended up with a more fermentable wort than you were getting in previous batches.
Which is the big reason I don’t stir. Unlike Ron, I didn’t find any increase in efficiency by stirring half way through. All that really happened was that I lost heat from the mash.
I stir . . . well, the motors at least, stir the mash the entire time. No temp stratification either!
;D
Every time I see that picture my jaw drops…
Obviously, you don’t have to open your cooler to stir, so you don’t have the issues we mere mortals do!
That is true!
But don’t count yerself as a mere mortal, Sir. My cooler is blue as well! 
It’s a picture of beauty!
just curious, how many rpm do your impellers turn? I’m piecing together a mash stirring system and am curious.