These are things that commercial brewers worry about more than home brewers but home brewers should be cognizant of them. My goal in home brewing is to make beers better than the ones I can buy. In order to do that I try to arrange things so that I don't experience the negative effects of autolysis (and I tasted plenty of home brew that suffers from it) or shear. Now I do use pumps - there really isn't much alternative but I try to use them as little as possible (which isn't nearly as little as I'd like).
As the DePiro article says, this is of particular concern to RIMS brewers because the wort is in constant motion and thus subject to lots more shear than in a conventional stirred mash. This would tend to cause me not to chose the RIMS approach.
OK, I know this is an old conversation, but I'm going through these considerations, so I was hoping to get a bit of fresh thinking on this.
First I'd like to say, I feel as AJ expresses here. We all do, I know - but for me, if there's the tiniest detail possible to improve, on the homebrewing level, I want to do it. Mostly that revolves around treating materials at every process juncture as gently as possible.
Two, on my previous system, I had no pumps. I manually vorlaufed by collecting in a huge ladle, laid it back over the grain bed. I manually transferred via the same ladle, to the BK.
I manually whirlpooled by gathering speed with my mash paddle. Once at a "good clip," (no, no way of knowing speed), I believe the total time from knockout to pulling the paddle was less than 5 minutes. Typically, I'd allow the whirlpool to settle 20-30 minutes. I might have steeped some hops prior to whirlpooling, but not always.
3. I used a 50' DIY copper IC. I don't recall how long it took, but it was acceptable. Obvious issues with coolant water and getting the final degrees to fermentation temp were always difficult. I am considering a closed loop now, whatever system I decide upon.
4. Finally, I obtained a tight cone and always got really clear wort into the fermentor; a point as rigorously important to me as a crystalline vorlauf.
So:
-concerned about hot break shear with a Chugger-driven WC. So, the need for a WP port is itself being questioned in my mind.
-somewhat concerned about cold-break taking place in a CFC or PC, and passing on to the fermentor. This is avoided with the IC.
-I will be able to jump up some in brewlength with this 20 gallon system. I don't know if an IC can cut it, though I know many here have no problems, and this Mr. Malty article on
chilling discusses exactly that. If it works, and can get 15 gallons down to 62, I'm in. Cheaper, easier to clean, allays some concerns over cold break in the chiller, gentle on the bitter wort.
Appreciate your thoughts, AJ and all.