But, after reading a comment from Denny the other day who said he heats his sparge water up to 185F (or something along those lines) I was confused. So I looked into Denny's batch sparging tutorial. It makes reference to doing a mash out, but also makes reference to getting the grain bed to 165F to 168F during the sparging process, but doesn't really explain why. I understand a mash out is to stop enzymatic activity. But once that has been done, what is the benefit of raising the grain bed temp to 165F to 168F during *edit* sparging? I'm sorry for the very long winded question, but I want to understand as much as possible.
I'll try to clarify things a bit....I used to believe in a mashout for 2 reasons. One was to stop the enzymatic activity and "fix" the fermentability of the wort. The other was that it would reduce the viscosity of the wort and improve the runoff. I've since found that in order to denature enzymes you need to hold 170F for 20 min. I've never done that, and I suspect not many homebrewers do, either. In addition, I realized that you're bringing the wort to a boil very quickly with batch sparging, so you don't even really need to worry about denaturing enzymes (the boil obviously does that To the second point, I realized that even if raising the temp really did reduce viscosity (and I question the extent to which that really happens), you got no benefits from it. I tried sparging with cooler water and didn't really see any change in efficiency or fermentability. In reality, even if I added 190F water, the grain bed still rarely reached 170. These days, I don't worry about a mashout step per se, but sparge with water that's at least 190F. That in effect gives me a beta/alpha step mash, which I think does increase my efficiency a bit by promoting fuller conversion in the mash.
And while it may or may not matter in this instance, keep in mind that John is almost always speaking of fly sparging, not batch sparging.
Thank you! That clarified a lot for me in one post. It sounds like adding sparge water that is heated to 190F is the most efficient thing in terms of actual benefit based on the options. Thanks again.