Amylase is an enzyme that breaks down two components of starch and complex carbohydrates to form maltose and glucose sugars. Amylase improves conversion efficiency and time by splitting barley starch molecules into partially-fermentable dextrins and maltose. Given enough time, amylase can dismantle the dextrins to maltose, glucose, and smaller dextrins. When fermentation begins, yeast will break the sucrose into glucose and fructose. It then consumes (more or less in order), the glucose, the fructose, the maltose, and finally the maltotriose. The dextrins will not be consumed. By helping to break the starches into maltose, glucose, and dextrins, Amylase makes more of the starch in the grain consumable by the yeast (resulting in a more complete fermentation and a higher alcohol content to the beer).
So, how do we use Amylase properly? I wasn't sure, so I did some digging.
Here's what I learned:
- Amylase can be added to a stuck fermentation to push it along, but it's best suited to be added during the mash.
- Enzymes in play during mashing will stop working at 168 degrees F (Fahrenheit), and this includes Amylase. Amylase works best at 147-153 degrees F.
- The recommended amount is 1/2 ounce for each 10 pounds of grain in the mash.
- If your fermentation is stuck, and/or your recipe included a lot of adjunct sugars, adding amylase to the fermenter (dissolved in sterilized and cooled water) can "unstick" it.
The recipe I'm considering brewing (a modified and smaller batch of the 21% beer above) has 8 pounds of grain in it. That's close enough to 10 pounds that I'm planning to put a half-ounce of Amylase in my mash water and use the iodine test to make sure it's all converted. I'm also going to add yeast nutrients in the boil and will oxygenate each incremental wort addition in the fermenter to keep the yeast happy. Hopefully that, combined with feeding the yeast the full batch of wort a little at time, will yield a brew in the 21% or higher ABV range.
More on that if and when I decide to brew this thing!