[KellerBrauer]

Kellerbrauer, I have a difficult time believing that mash thickness would have an effect on efficiency. Efficiency is the extraction of fermentable content from the grain solids into the water. As long as the starches and sugars can get out of the kernel material, it seems that the amount of water they dissolve in should have little effect. However, I can believe that the activity of enzymes could be affected by mash thickness.

Thank you  Martin, I appreciate the help. I think I’m going to go back and reevaluate my process and my numbers from my recent brew.  Now you’ve got me thinking....

[denny]

Martin, can you comment on the fact that a lot of malsters and other sources say that most of the conversion takes place in the first 10 minutes of the mash?  Although I agree that mash pH tends to rise throughout the mash,  I have always been a bit of a stickler to assure that I within the 5.2-5.6 range (at room temperature) early on because the enzymes are happier during the time period where the bulk of the conversion takes place.

That comes from commercial brewers.  As you well know, mashing in can take an hour or more and lautering even more than that.  All the while you're in conversion range.  So they may only rest for 10 min., but they're actually mashing for much longer.

[Robert]

Martin, can you comment on the fact that a lot of malsters and other sources say that most of the conversion takes place in the first 10 minutes of the mash?  Although I agree that mash pH tends to rise throughout the mash,  I have always been a bit of a stickler to assure that I within the 5.2-5.6 range (at room temperature) early on because the enzymes are happier during the time period where the bulk of the conversion takes place.

That comes from commercial brewers.  As you well know, mashing in can take an hour or more and lautering even more than that.  All the while you're in conversion range.  So they may only rest for 10 min., but they're actually mashing for much longer.

Yep.  When you read commercially-oriented manuals, you find they use terminology differently than we do.  (This can be troublesome when trying to decipher old records and recipes.)  Commercially,  "mashing" is the period of mixing, of mechanically stirring the grain evenly into the water.  This can take well over an hour.  Then "resting" is the period when the mixing apparatus is shut off.  This may only require a short time to allow the grain bed to settle for runoff in an old-style combined MLT, or to ensure complete conversion before mashing off and pumping over to the lauter  tun.   So they're in conversion range for a longer time than we are in many cases, especially in a temperature programmed mash where lengthy mashing and short resting are repeated as each temperature is achieved evenly throughout the grain bed.