peebee
Out of Control
Not "scientifically proven" you say, but a very good illustration of what's goin' on (or at least confirm my opinions ... I'm not "scientifically proven" either).When the kids were littler and I had less time I used to overnight mash so I could get everything done quicker in the morning. I had much better efficiency than a normal 60 min mash. I wouldn't say I had higher fermentability as my beers generally stop at 1010 whatever I do. I think they possibly had more body to them, but wouldn't say that was scientific ly proven.
Many plant enzymes just act faster and faster with more heat. Up until the point the heat destroys them. So, the optimum temperature is the one that the job can be done the fastest before the enzyme expires. For beta-amylase that is relatively cool, alpha-amylase is much more resilient. So when overnight mashing, most beta-amylase (which is creating maltose) is destroyed before you go to bed, whereas alpha-amylase ("randomly" chopping up starch and longer chain dextrin into shorter chain dextrin) goes on, finding the hard-to-reach starches and thereby increasing efficiency, but not necessarily fermentability (producing more dextrin, although most - not all - brewery yeasts these days can ferment short-chain dextrin, or "malt-triose").
I was mentioning "Chavallier" barley malt earlier. Mashing longer to give, what appears to be, lower beta-amylase amounts time to act. I should have added I keep the temperature lower too (62-64C) to also give the beta-amylase more chance to do its job.