Mash Times?

As I sit here watching my mash mash a thought about the times come to mind.
Most agree that a low temp long time results in a good yield of fermentable sugars. Conversely a higher temp and shorter time results in a sweeter less fermentable wort.
So wouldn't the sparging time and sparge water temp influence the fermentables?
I'm trying to achieve a sweet wort and the recipe is calling for 159F at 45mins.
So if I fly sparge for an hour whats the point of achieving 159 for 45 mins, because the temp is going to drop in that time?

when you sparge you should do so with much higher temperatures, say 170 which will denature the enzymes and stop conversion. Your 159 will probably denature the beta amylase in 45mins anyways.

read this (section 4.3.4): http://books.google.com/books?id=zV...nd+practice&ei=4r-pSf_RC6TCMZvgwO8I#PPA104,M1
and actually the whole book is a good read.

btw, nice bike, I'm looking at sucking the orange kool-aid soon, but might go with a husky.

Most of the enzymatic reactions with modern malted grains occur quickly. The enzymes are denaturing as soon as the water is added - especially the beta amylase as it prefers lower temperatures. The sparge water temperature is usually higher - trying to achieve a temperature in your mash tun of 165-170F. This will rapidly denature whatever enzymes are left and "lock in" the fermentability of your wort. Also adding the sparge water dilutes the enzymes and substrates which will further slow the reactions down.

The take home in all this is to have a consistent process and tweak the mash in temperature as needed to get the fermentability you want.

GT

Thanks guys appreciate the input.

Also a 170 deg sparge extracts more sugars, leading to higher efficiency. (Don't go higher in temp as that leads to tannin extraction).

As for mash.. long times at higher temps wills till do about the same thing as a shorter time.

Todays malts often can covert in 30 minutes. Some on this forum don't do a mash longer than 30 min. I tend to do 60 min mashes regardless of temp because I'm anal and like to make sure it's all converted plus I end up doing something else during the mash (like remember I need more propane) and need that hour. lol.