Something else I haven't seen mentioned yet - you suspect diastaticus as the culprit, but most STA1+ yeasts that I'm familiar with are POF+ as well. Any off flavors of note on these gushers?
Other random musings:
Beer stone may provide nucleation points that could trigger gushing
Possibly the yeast went into dormancy before it hit its max attentuation somehow? Maybe the process of racking and priming woke them back up? What temp are these being stored at? If its cold enough maybe the yeast is going dormant.
with a considerable further attenuation the flavour changes and i get some esters and i believe diacetyl increased and it does throw off the flavours i noted at bottling.
thinking hard about it today, im thinking it is simply incomplete fermentations for whatever reason with some yeasts. i was attributing this to hop creep several months ago, not sure if i mentioned it here.
thanks, i will just try to fix this from a few potential angles
I've tried to make hop creep happen several times so I could study it, but I couldn't get it. I recently brewed a batch with over 12 oz of dry hops per 5 gal and still couldn't get it. I don't believe it's as common as many think.
not sure what to say, but it may be a matter of my, others, and/or your process.
you dryhop at ~34F, right? do you run the beer through a plate chiller after? if after that point you store the beer at 40-50F temps ie. fridge temps while it carbonates in a keg you might just have whatever ale yeast kept cold enough that it inhibits any further fermentation.
not sure if this is what you do or if this would even in fact inhibit the "hop creep", but perhaps?