Yeast Harvesting after using Amylase Enzyme

I would like to make a series of low gravity beers similar to these popular HBT recipes,

https://www.homebrewtalk.com/showthread.php?t=123937
https://www.homebrewtalk.com/showthread.php?t=66503

Skip to the end of this paragraph if you just want to the question and don’t want to read the explanation. I plan to do one low OG beer every third batch or so for a few reasons. I’d like to have a refreshing sessionable beer on tap, especially on hot summer brew days. Mainly, this is cheap practice and experimentation, without yeast (repitched) and with bulk ingredients I can crank out a beer similar to the BMC clone for around $15.00 per ten gallon batch. These types of beers are good for identifying problems in my process because there’s not much flavor to hide behind. For the same reason, they also allow me to try new ingredients to get a better idea of what kind of flavors and qualities they produce. Lastly, this seems like an ideal way to produce healthy active yeast to repitch into my normal and high gravity beers. I’d like to add amylase enzyme after primary fermentation to dry out and get the most out of the low OG beers. The process I would like to use is, add the enzymes (1 tsp per 5 gal) to the fermenter after primary fermentation, cold crash once target FG is reached, rack the beer off the yeast cake into kegs then rinse and store the yeast cold or repitch directly into new batch. I’m concerned that without denaturing the enzyme in some way, enough will make it into my repitched yeast slurry to alter the FG of my next beer.

Additional information: I do my primary fermentation in carboys in a hold/cold temperature controlled freezer. When I rack of the yeast cake I leave behind less than a quarter inch of visible beer. I rinse with 1.5 quarts of boiled and canned room temperature water and then decant twice to collect a pint of the best cross section of yeast.

I can't answer your question about repitching the enzyme, but I'm really curious to why you think you need it in the first place. You shouldn't have any problems drying any of those recipes out with normal practices - mash techniques, pitch rates, fermentation schedule etc. I'd be worried that the beer would be over-attenuated and thin, especially since these are low OG recipes, and not excactly the fullest of beers to begin with.

I would suggest that the enzyme will indeed carry over. I have no basis other than I simply think it will.
Personally, I would harvest the yeast at starter time. It's better practice anyway than harvesting from the fermenter. This would eliminate any chance of introducing amalayze to future brews

Amylase enzyme helps convert starch to sugar, it is best used in the Mash. You are better off crushing in a Beano tab for what you are doing, cheaper than wasting pure Amylase.

amylase will indeed help break down some of the starches left unfermentable. It will do it painfully slow at ferment temps though. Mashing makes use of amylase (and others) but it is denatured during the boil

Thanks for the replies. I think I'll still try using the amylase enzyme once just for the experience, but keep it far away from any yeast that I plan to repitch as you've suggested. The reason I wanted to use it in the first place was that it was seemed to be important in the first recipe I linked to.

the reason the other guys were warding you off the amylase is because it really will be close to useless to you. Low OG beers spend very little time in the fermenter, at least they should. The enzyme has an optimum temp range of 155-167F, thats when it does its best work. At fermenting temp, it is still working but incredibly slow. It would take weeks to see any appreciable difference. (on a much bigger than 1.030 beer)
The suggested Beano which is a different enzyme all together may be the better choice if I were to suggest any at all.....which I wouldn't. The recipes you posted require no further breakdown unless you want weak water. They are 1.030 beers to begin with. Any thinner and you aren't actually making beer anymore

just for interest, the claim that the amylase caused explosive fermentation in secondary can't be anything but false. I believe what the poster saw was co2 coming out of solution. Amylase doesn't work that way