I’ve brewed an American Lager and its finished out at 1.010 SG. I was thinking of adding some amylase enzyme to see if I could get the gravity down a little more. I worry about adding potentially contaminated material to by beer and causing a bacterial infection. Could I mix the amylase enzyme with 100% grain alcohol to sterilize it or will doing so deactivate the enzyme?
If you mix it with 100% ethanol it will disrupt the hydrogen bonds and denature the protein. It is possible it is a reversible process and the protein will reform the proper fold when you add it to the beer, but it will more likely coagulate the whole thing and it won’t work the way it’s supposed to when you add it to the beer.
You’re in a similar situation with an acid sanitizer, it will denature the enzyme - that’s one of the ways it works to sanitize. Heat denatures proteins too.
I wouldn’t worry about contamination so much, but I don’t think you should add any amylase either. I don’t know where it started, but 1.010 is pretty good and amylase is not a controlled way to dry out a beer - it’s not like you can add 1/2 tsp per gallon to drop it 2 points, it doesn’t work that way. Make a recipe adjustment for next time, and jack up the carb for this batch to increase the perception of dryness.
If you’re going to go ahead and add it though, just add it straight.
Thanks Tom for the reply. The OG was 1.051 and the recipe target FG was 1.008 so 1.010 too bad of a miss, especially considering it was my first attempt with this recipe. My interest in adding amylase is just curiosity and my desire to brew something my wife might actually drink (lighter beer). I bew 10 gal batches and split the batch between carboys, so my thought was to add it to half the batch and see what happens. I guess the risk is potentially turning a nice 5.3% alcohol american lager into 7% alcohol jet fuel (that my wife won’t drink either). I guess the question is, is it worth potentially ruining 5 gal of good beer to learn something.
Jason
You can always do it in 1-gallon 
I added amylase once according to the directions and then didn’t get back to the beer for a few weeks, maybe more. It took it from 1.02+ down to 1.001. I had to add maltodextrine to add body back to it. It turned out to be a great beer, but it was kind of a pain. I would do it again maybe, but not for dropping something .002
Since you’re looking for such a small drop in SG use less than directed, you need to have yeast in there, and watch it really closely. If you decide to do it that is.
The Tubercle suggest leaving well enough alone.
At least in this case ;D
Next time throw some crushed up Beano tablets in the mash tun. Might want to spit in it a couple of times - saw that one on the History Channel.
Sound advice but fixing what isn’t broken is kind of my SOP… I think I’ll just take a gallon and experiment on it to see.
I have one more question about amylase though, what kind of shelf life does it have? I have some unopened bottles of it I bought for a Miller Lite clone I attemped about 6 years ago. From what I’ve been able to find on the web, I think there may be a shelf life of about 1 year. BTW, the Miller Lite brew turned out pretty good in terms of hitting the target. FG was 0.9998 and it tasted like beer tainted carbonated water. My wife actually liked it.
My God, man. The Humanity, the Humanity of it all. Why?!!?
yeah, yeah, I know, all of my beer friends said the same thing. From a brewing challenge point of view though, light larger beers don’t have any actual flavors in them to hide brewer errors. I figure the effort will improve my overall process and make my real beers better. At least that is my story and I’m sticken to it! Plus, as I said, making something that my wife will drink is good too.
Amylase Enzyme is a great way to very quickly ruin a beer, if that’s what you are after, go for it! 
Even in the cases where I tried to “fix” a stuck fermentation with AE, I ended up dumping the beer anyway. In your case, I would leave well enough alone. Doesn’t even seem like you have anything here that needs fixin’.
I hear you. What actually happened when you tried to use it to fix a stuck fermentation that ruined the batch?
Quick, give me my nitroglycerin ampule… :o :o :o
Once it dried out to rocket fuel, the other time it picked up a really weird off flavor I never could get my head around - almost like tequila - some sort of infection I suppose.
In your case though, I just don;t see what you are concerned about. 1.010 should be plenty dry enough. Even if you could shave another 2 points I doubt you would notice much flavor change.
What about thinning it out with water? It would be controlled and has precedent.
We were going to do this with a “wife demanded clone” of Michelob Ultra Tuscan Grapefruit. We overshot the gravity by 25% (new mill) and it finished at 1.010 but could add a gallon of water should she not like the body. Turned out that we beat that citrus bomb in the uncarbonated/warm taste test at bottling. Still carbed it high for her.
And it’s not my wife. She doesn’t drink beer at all.
So, I’m confused. If that’s the case you’d think she’d drink Michelobe Ultra…
I’m pretty sure that she’d say that it tasted too much like beer. I still haven’t figured out what that means. All beer, some ciders and a few wines, dry whites, mostly, evoke that comment.
It’s my friend’s wife. I actually have no idea what this Mic tasted like. Something like watered down grapefruit juice, I think. And I hit the nail on the head, just a tad heavy handed.