Hmm. . . . very interesting. I never thought about it as a shearing issue, but that might make some sense. I am guessing that ajdelange was eluding to the fact that shearing the wort during mash can lead to a
shear thickening effect, which would explain a resultant problem lauter/sparge (if the viscosity increases sufficiently, then it will be hard to get wort to run). This makes sense to me with regards to a fluid flow problem, but I am trying to understand if it could have an impact on efficiency, fermentation issues, haze, body, head retention and last but not least, taste.
How would shear stress impact these issues?