Lesser of two weevils.

I am curtious to hear, umm read, thoughts/speculations from the panel on the microscopic (enzymatic, protenatious, acidification, etc...)impact between two popular methods of mashing.

The first (derived by Conrad and Fix) employs a cold dough-in, recirculation, and direct heat to the target rest temperature. Essentially involving a drive by scenario through all the subsequent rest stages up to the target for an indeterminate amount of time (dependent on the heating efficiency of the system and the btu's applied).

The second involves Infusion of a large mass of water at temps above the threshold of denaturization with the result of heating loss in the mass of grain to the target rest temp.

No doubt there is some level of chemical reaction and enzymatic response, perhaps insignifigant in the big picture, but what is that level and what is likely occuring within the two methods?

From what I have read and learned from breweries, the first scenario is more important for poorly modified malts, and some particular beer styles. The latter (which is used by me and most brewers I have spoken with) works just fine for highly modified (modern) malts.

I doubt there is any denaturation taking place in the hot water/cold grain infusion procedure for two reasons. First, it takes some time at temperature to denature an enzyme, and the time it takes for the hot water and cold grain to equilibrate and drop the overall temp below the denaturation temp of the amylase enzymes isn't long enough to do any harm. Two, the enzymes are less susceptible to denaturation in their dry state than when they are hydrated and dissolved, so even if they experience denaturation temps when in the dry state, they are safe.