I don't get it?
91% is only 91% of the 80-82% extraction the lab got for analysis purposes. Why would your wort quality deminish? As long as your ph doesn't rise ove 5.8-9 and your gravity doesn't go under 1.008 you shouldn't have any problems.
Every lot of malt has an analysis tag or paperwork from the lab giving their extraction plus/minus crush specs and figures are included.
Some malts are up around 39 points, were others may be 33 points. This is all done using highly accurate scales and weighing everything. They do not use volumes.
When you are figuring your efficiency, are you using certified scales and using scaled weight on all componets, or are you using a combo of volumes and weights? Do you use a generic number when calculating your efficiency, or are you using the analysis specs for that/those specific malting(s?
why do you think you need to back off?
To my knowlege, if your pH is high, the gravity wont really matter. Maybe I am wrong.
I do have the specific malt analysis for the malts that I use. This # has been calculated over a series of brews, where my brewhouse has also matched the 83% eff. that I have achieved for the past year on my HERMS. I also have a digital pH meter so that I can verify my pH.
I want to sparge less. Doesnt make sense to me that brewers sparge with more water, the smaller thier grain bill gets. That seems, counter intuitive.
My system has been very well dialed in, so much so that volumes and gravity readings never waver from 82-83% brewhouse eff. and 5.5 gallons post boil volume. In fact, I drain both my MLT and HLT dry to reach my pre-boil gravity.
This being said, I personally want to strike a balance between grain bill size and sparge water volume. This is why I have begun to predicate my sparge water volume on the grain bill size. The larger the grain bill, the more I sparge, the smaller the grain bill, the less I sparge. Exactly opposite of what is conventionally done.
But, this thread isnt about efficiency people, it is about malt conditioning. Just saying, we can start another thread if you like.
Malt conditioning rocks, that is all. And malt conditioning doesnt affect eff. in any way... soooo