Beer Forum

I understand that different enzymes are activated at different temperatures, but I'd like to know more about the role time plays in denaturing one set while activating another, more then simply: If I mash @ 145 for 60 minutes, and then raise the temp to 155 and hold for 15 minutes, I get an extremely fermentable wort, without big residual sugar character that you'd get if you spent an hour @ 155. Does it have something to do with a finite amount of starch in the grain that if it spends most of its time converting at a lower temp, then the sugar profile is more or less set, and raising the temp just activates new enzymes that finish out whatever unconverted starch is left, rather then changing the entire sugar profile of the mash?

Kazi the Younger wrote:Does it have something to do with a finite amount of starch in the grain that if it spends most of its time converting at a lower temp, then the sugar profile is more or less set, and raising the temp just activates new enzymes that finish out whatever unconverted starch is left, rather then changing the entire sugar profile of the mash?

Yes. That and the fact that most conversion is done in the first 15 minutes.

thanks for the reply. So if most of conversion is done in the first 15 mins, what would happen if you mashed @ 145 for 15 minutes, and then ramped up to 155 for 60 minutes. Would the majority of your fermentation profile still be mostly defined by the 15 minutes spent @ 145, or by the 60 mins spend @ 155?

Kazi the Younger wrote: Would the majority of your fermentation profile still be mostly defined by the 15 minutes spent @ 145,

That's my understanding. Noonan claims "A variation of two or three degrees for even five minutes will dramatically alter the maltose/dextrin ratio of the extract" (p. 140, [it]New Brewing Lager Beer[/it]).

interesting. I'll have to give that book a read.

Yes, it is that there is a given amount of starch present and that the enzymes active during the initial part will be the first ones to take a crack at it. If you hold it at a lower mash temp for a certain amount of time, and ~ 70% of the starch gets converted to maltose, then raise it up, the ~30 % left will convert to dextrins (with some overlap). On the other hand, if you start out hot, the starches will get chopped into dextrins, leaving a not very fermentable wort. The high temperatures may denature some of the maltose producing enzymes, so allowing the temperature to drop may not result in a more fermentable wort, even if it is kept in the lower range for a longer period of time if those enzymes are no longer functional.

That´s a good post for "something of value", spiderwrangler