Ok, let me back up. I'm looking at the pros and cons of a mashout. My system is pretty much dialed in and very consistent on OG/FG and hitting targets. One my last batch I opted to
not do a mashout in order to gain additional volume for the mash to help control pH. That being said, I was commenting that the #'s didn't really change for me, comparing the readings from prior batches where I
did do a mashout. While the whole mash-out/no mash-out question seems to be a matter of personal choice as my #'s didn't change, what I
did learn was that the lag time in getting the boil off could change the beers profile as the enzymes continue to break down starches well after the mash was done and the best way to stop that was the mash-out. To "lock" in the profile.
The whole mash/no mash (for me) will depend on the pH I need to control (esp with alot of crystal malts), that being said, and turning focus on the runoff, I currently allow the kettle to fill 100% before I light the burners for the boil. The only reason for this was for me to get a pre-boil gravity reading. If I change my process, to start heating the runoff before the sparge is complete, there is a chance the runoff will be at or very near boiling temp as the fly sparge takes about an hour.
Now to bring in my above mentioned question, since the runoff will already be at or near boiling temp once the sparge is done and I go to take my "pre-boil" gravity reading, how will the fact that I'm at or near boiling change those readings
compared to a batch thats been sitting there cooling down while the sparge finishes.
I'm not concerned with the fact its boiling, I have a ATC Refract so its fine. I'm just curious will there be a difference?
Keep in mind though that the rate of enzymatic activity in wort decays quite substantially as time goes on. The difference between, say, 90 minutes at mash temps and 120 minutes at mash temps isn't going to be dramatic. It's something, and thus perhaps worth doing if you're really trying to rein in your process, but it's not as though you'll be looking at completely different beers.
As a completely new question, what time frames would the changes be noticeable to the final outcome of the beer?