Brewing with additional apha amylase - how much to use?

[frankvw]

Hi everyone,

I'm experimenting with alpha amylase to increase the fermentability of malt extracts by breaking down some of the complex sugars and other hard-to-ferment components. So far I've managed to get a DME that otherwise won't go below 1.014 all the way down to 1.006 over the course of about 3 days at room temperature.

Note: the amylase powder I have is cut with dextrose (4% amylase to 96% dextrose) and intended to saccharify starches at 70C / 158F overnight.

Before I go any further, I'm wondering what the general consensus is on how much amylase enzyme to use on, say, a 5 gallon batch. I add the amylase along with the yeast. As I understand it, the enzyme works as a catalyst and is not consumed during the breakdown of complex sugars and starches, so, given time, a small amount should do the trick, even at ale fermentation temperatures.

Your opinions?

// FvW

 

[brewingupastorm]

A tbsp according to many sites, but i'm not sure how much gravity it will gain you.

 

[bracconiere]

i use gluco, i get bone dry with 1 gram a gallon, most of the time......sometimes it takes 2 grams a gallon...

 

[frankvw]

A tbsp according to many sites, but i'm not sure how much gravity it will gain you.

It depends on wort composition. Dry malt extract can be high in oligosaccharides and dextrins, but I have a feeling (note how I phrase it) that the enzyme I have works better on the oligosaccharides than on the dextrins in the DME I have. Still experimenting, though. So far I've seen attenuations from 1.047 to 1.014 without and from 1.047 to 1.006 with alpha amylase on a DME-only test wort, and I'm testing to find the minimum amount of amylase blend (4% amylase on 96% dextrose) that I can get away with.