"I've used the alpha and gluco from Brewhaus (BA-100 and GA-100). I've also used SEBstar-HTL (alpha) I get from Enzymash. I plan on using SEBamyl-GL (first time) on Wednesday for one of my rice mashes (instead of the GA-100). So those are the only commercial enzymes I've used to date.
Basically, the alpha is used for liquefaction and the gluco is used for saccharification -- that's the high-level differences between them. Alpha-amylase is an endoenzyme and alpha-glucosidase (sometimes called glucoamylase or gamma-amylase) is and exoenzyme. The prefix "endo" is from the Greek "endon" meaning "within." Therefore, endoenzymes can randomly attack bonds "within" a chain. The prefix "exo" is also from Greek but means "outside." So exoenzymes can only attack certain bonds on the outer edges of a chain.
Endoenzymes, due to their ability to attack points at random, are typically used to lower the viscosity of the starch substrate. When the chains are long, the potential targets are many. So, an endoenzyme (the alpha) tends to act quickly, breaking long starch chains into smaller ones ultimately producing a less viscous and more manageable substrate (liquefaction). In the process of chopping up long starch chains into smaller ones, endoenzymes leave behind many starch molecules that have not been completely broken down. But this also exposes many more outside ""edges,"" leaving them vulnerable to a more effective attack by an exoenzyme (e.g. gluco). After liquefaction, the slower acting exoenzymes have many more targets, so they can happily remain busy lopping off one glucose or maltose molecule at a time (saccharification). Basically, alpha-amylase is the chainsaw and glucoamylase is the wood chipper.
Anyway, you can add some alpha to your mash if you're using a base malt to help out with the liquefaction ... and when things cool down a tad, drop in some gluco to help out with the saccharification ... especially if you're doing a single infusion as the gluco can potentially break down some of the limit dextrins left behind by the alpha. You can also add some gluco to your AG wash during fermentation to help convert some of the limit dextrins. BTW: glucoamylase can work on the a(1,6) bonds as well as the a(1,4) bonds (they can attack the branch points that the alpha can't get to).
You could also use just the commercial enzymes without any malt. The pH and temps of the BA-100/GA-100 overlap, so you could potentially adjust your pH and temp in the overlap region and apply them together, but I never tried that (I do two separate applications after adjusting pH/temp for the task at hand).
As for cost, the commercial enzymes are pretty inexpensive even for hobbyists. The problem is finding a reliable source and decent documentation. Brewhaus and Enzymash, IMO, are the best sources for folks in the U.S. Brewhaus supplies the powdered enzymes (BA-100/GA-100) and Enzymash provides the liquid enzymes (SEBstar-HTL/SEBamyl-GL). The SEBstar-HTL is more temperature tolerant (up to 90 C) so if you're planning on boiling corn you might want to take a look. For rice, I actually prefer the lower temperature BA-100 (I don't boil, I steam ... then add the strike water).
As far as price per pound of grain, I think the liquid enzymes will give you better numbers but I also think the powders are easier to work with. But do your own math ... and keep in mind that shipping can be more costly than the product itself. For some rough estimates: I plan on about 1 gram/lb when using the powdered enzymes (BA-100/GA-100), and roughly 0.3 ml/lb when using the liquid enzymes (SEBstar-HTL/SEBamyl-GL). If I recall correctly, shipping included, I paid about 30 USD (total) for 4 oz each of BA-100/GA-100, and roughly the same amount for 100 mL each of the SEBstar-HTL/SEBamyl-GL.
I really didn't intend to be so long-winded, but I find the whole enzyme thing pretty damned fascinating, so I figured I'd just do a brain dump. Hope this is helpful.
Regards,
--JB"
