I kinda had this discussion with my LHBS as well. And didn't get any more convinced either way than i was before I went in the store. He gives me his beer judge opinion, and I let him think that I take it as gospel. We maintain a pleasant relationship that way and avoid argument. Did I mention I am an engineer and agnostic? Show me. His opinion is that fly sparging is the epitome of aeration but delivers the best efficiency. I.E., a tradeoff of HSA for better grain efficiency. I have to agree that dripping small jets of wort back into the bed couldn't be much worse for aeration. The splashing doesn't have to be the magnitude of a toilet flushing to be a bad thing. Little splashes that last a long time are just as bad. Then, he tells me that if I'm not boiling vigorously enough, I'm not going to get the best protein break-down. Wait a minute. Seems like a contradiction in terms to me. If HSA is going to be the root of cloudiness or otherwise bad beer, and I can't vigorously boil without HSA, how the heck am I EVER going to make a clear beer without finings? (I know it can be done, so I keep trying). I'm starting to think there's no such thing as a clear beer without finings or expensive ceramic filters. I've done a gentle rolling boil and one that wanted to continuously run over, and point blank, absolutely no difference in the outcome (other than nearly scorching the latter). None I could detect, anyway. I'm that guy, that when driving down the road and I see the driver's arm extended out the window, I do not take it to mean they are turning or stopping. I take it to mean the window is open. That is the only truth I can discern from seeing the arm.
So, just to add a new wrinkle to the discussion, what about doing hot transfers with vacuum? I can't think of a better way to remove air and keep it out of the wort. That certainly takes some more sophisticated equipment though, and much higher quality seals on hoses and fittings.
Everything I've read is about pressure transfers being the safest way to handle the wort because the CO2 will eliminate the effects of splashing in air. Ok, I can see that keeping baddies out of the tank. But riddle me this: If the wort already has air dissolved in it from fly sparging, transferring, boiling, and transferring again, how is a positive pressure on the vessel going to get that aeration OUT? It cannot and will indeed keep it in there longer doing exactly the opposite of the intent. Putting it under vacuum for at least a short time would indeed help devoid the wort of dissolved air. Contradictory, though, the yeast needs the air/O2 to propagate and do what we want done. It's a bit of a conundrum. How do we keep the bad air out and still leave the yeast something to live on?
I say the jury's still out on this one. I may one day be swayed and will maintain an open mind about it until then. For now, it looks like the purest way to give the yeast what it needs and achieve ZERO aeration issues would to be to pull a vacuum on the fermenter first, then start injecting pure O2 in to aerate with the right stuff at the right time, and then finally inject the yeast into the purest wort possible. Cut off the O2, and seal it up for fermentation. This just sounds expensive and quite possibly unachievable, or at least a lot more costly and troublesome than I'm willing to invest on a hobby. But, I'm willing to invest in things that will make a real tangible difference. Then, finally, what if the yeast quits (high alcohol level, etc) before all the O2 is used up? Uh oh. Now I've done it.
One thing I'm learning about the whole process is that the closest I will ever be to becoming a brewing purist is if I can at least learn enough about hops, malts, and yeasts to keep a 'style' of beer at least something similar to the country from whence it originated. But I'm also learning that stuff from different places makes purty good beer. Guess I'll just be a brewing mutt.
