thanks for the response. Good to know I can reuse the yeast. I didn't know if the enzymes that reduce the gluten would stick around.
I actually emailed White Labs about this. It is an enzyme that is not denatured by fermentation. But they also said "As for secondary use, it is very likely you will not get the same results from Clarity-ferm in that the gluten reduction would be less than the first use."
I have reused an entire yeast cake from a beer that I used Clarity Ferm (CF) in. The second beer was 3 gallons of a lower-OG beer, with positive results (i.e., without lab testing as proof, it seems to have worked).
The amount of gluten is proportional to the amount of malt used. Wheat has a higher concentration than Barley. Adjuncts like corn, oats, sugars of any kind, have none. So if your first beer is a wheat beer, I wouldn't trust it to work twice. If you are "washing" yeast and/or only saving a portion of it, there won't be enough of the enzyme around to work again. If you reuse the entire yeast cake from the first beer the CF was pitched in, and that was a non-wheat beer of standard gravity (and/or used gluten-free adjuncts), and your second beer is a lower gravity beer and/or uses gluten-free adjuncts, then I am confident you will get gluten reduction in the second beer. I probably wouldn't go more than 2 beers. But planning things out right, you get the savings of a yeast pack and a CF pack in 2 beers!
More info... CF is an enzyme that is a proline-specific protease, and since gluten protein is proline-rich, it reduces it by essentially breaking it up into constituent parts. It was developed initially/ primarily for haze reduction and I'm guessing the effect on gluten was a very nice coincidence, and gluten sensitive people are just lucky! Side note, White Labs doesn't actually make it, they are certified by DSM to distribute a diluted version of Brewers Clarex, which they market as Clarity Ferm. Furthermore, the homebrew vial is actually a diluted form. Actually CF only requires 2mL per 5 gallons of standard gravity all-barley beer.
