Beta-amylase vs alpha-amylase

[amarks6]

Probably a naive question, but.....

Does the time spent mashing in the beta-amylase territory (60 - 64 degrees) limit the amount of time you can spend in the alpha-amylase territory (68 - 72 degrees)? In other words, is there a finite amount or starch to be converted and if you convert it all at lower temperatures you're going to get a very fermentable beer?

 

[Blind Dog]

This explains it better than I can: http://braukaiser.com/wiki/index.php?title=The_Theory_of_Mashing

 

[Rocker1986]

Well there has to be a finite amount of starch, otherwise the mash would go on indefinitely and you wouldn't have to use different weights of grain to achieve different OGs.

I think basically the more time spent in beta territory, the more fermentable the wort ends up being.

In my pilsners I use rests in both territories. Usually 40 mins at 63, then 30 mins at 71. Still end up with FG's below 1.010, but do get very good head retention, and the body of the beer doesn't seem at all thin either.

 

[amarks6]

Wow! That's fantastic! Thanks guys.

 

[Lyrebird_Cycles]

Yes, but it takes a surprisingly long time: I make a beer that starts at about 16 oP* and I'm trying to get it to finish below 0oP. A six hour continuously rising mash (50 oC to 70 oC in 2 degree steps over the six hours) got me to 0.7 oP, I'm going to try running an overnight mash next time.


* It's not all malt, there's some help from glucose and fructose.