The main concern with diastaticus yeasts is a lower than expected terminal gravity. Diastaticus yeasts are capable of producing amyloglucosidase which can break down the unfermentable sugars that contribute to final gravity in beer. Since mead and cider (and other fruit wines) are mainly fully fermentable sugars to begin with, diastaticus yeasts aren't really a concern.

[–] [email protected] 2 points 1 year ago* (last edited 1 year ago)

Diastaticus is more of a concern for breweries if it gets into batches where it wasn't planned for and continues to lower the final gravity due to the introduction of glucoamylase. If the product is packaged to soon it will lead to very bad outcomes with bottle/cans blowing up.This has even caught some very large breweries (Left Hand vs. White Labs comes to mind) but has more often happened at smaller breweries in the last couple of years. Not a fun experience - I know from first hand experience.