I've got a package of Clarity Ferm with 2 dates stamped in ink on the back of the package:

NOV 11 2016    JUL 22 2017

I bought it from an online retailer about 4 months ago (March 2017).

Does anyone know what to think about the dates? Should I use it by JUL 22?

1 Answer 1


Clarity ferm is an enzyme to help reduce chill haze.

The dates are production date and use by date.

Because it's an enzyme it may not be stable and breaks down or denatures over time.

Using it past the use by date won't harm the beer. But it may not work if there's no enzyme left.

  • Okay, so that's slightly more than an 8-month shelf life. Thanks.
    – Jeff Roe
    Jul 9, 2017 at 1:39
  • 2
    I agree with this answer but might add that enzyme life depends a lot on storage conditions - temperature being one of the more important variables. Generally the shelf life is given as the optimal use time. it is rare that a packet of enzyme becomes totally non-functional on the "use by date". That date is usually set some time in advance of any real deterioration of the product. So using by the "use by" date often implies that (say) 90% of the enzyme is still active (hence USE by). IMHO, one can be much more suspicious of packets that are 50% beyond their "use by" period. Jul 9, 2017 at 9:04
  • @barking.pete the enzyme is Aspergillus niger prolyl endoprotease AN-PEP, most effective at 98.6°F and 5.5ph. When applied as a gluten cleaver, brewers chill wort post mash and pre-boil to 98.6 and whirlpool until gluten is degraded. Lacking other tech info on AN-PEP we can safely assume that it denatures in most mash temps maybe as low as 120°F. So it's best kept cold, the shelf life may just be a labeling requirement for food stuffs or for marketing to get people to repurchase if it's "old". Jul 9, 2017 at 13:26

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