I have read and heard the majority of starch conversion happens within the first 20 minutes or so of the mash. I am actually doing a bit of research on this. So here are my questions.
I use beer smith and have it set to were it accounts for not preheating my mash tun. I use a 48qt picnic cooler and always do 5 gallon batches. I rarley take temp readings through out the mash, always at dough in though. But yesterday I was inclined to do so, when I doughed in I was hovering at 159, I poured some cooled water in to get it down to 154 (which is were I wanted it) I checked the temp again at about 30 minutes left in the mash it was already down to about 149*. I am begining to think that it is vital for me to maintain that desired temp through out the mash.
Doing 5 gal batches does leave me with a good pit of open space in the cooler.
Do you think this is vitally effecting the flavor of my beer? My effeciency is coming in good yesterday it was 86%