Hops can break down starches

[Veets]

Hops can break down starches to give more fermentables. Cool summary here.
https://www.scientificamerican.com/podcast/episode/beer-fermentation-hops-along/
If this has been reported before then I missed it.
Now the question I have is whether the pellet-making process denatures those enzymes, so you'll only get the effect with whole hops.

 

[day_trippr]

It's been noted, mostly wrt kegging too soon after dry hopping and ending up with diacetyl from the unexpected additional fermentation.

I'd be surprised if pelletizing would significantly affect anything in the hops - all hops are lightly kilned to dry them to a safe level, then some are sold as is, some are pressed into plugs (much less popular than when I got started) and the rest get smushed into pellets...

Cheers!

 

[Northern_Brewer]

I assume this article is based on the paper that came out back in June or so - it was discussed quite a bit at the time, although it's not a new effect. Ron Pattinson has found studies going back to the 1890s! But it's never been a particular issue until people started such massive dry hops, and varieties like Mosaic seem particularly prone to it.

Given that the enzymes survive the dry process, I doubt the pelleting process will have much effect on them.

 

[Veets]

Thanks!
As for pellet hops, I wonder if it's such a straightforward situation.
I've read that hops kilning is done around 150F, and amylase denatures around that temp. BYO article says that beta amylase can be completely destroyed in 5 minutes at 149F. https://byo.com/article/understanding-enzymes-homebrew-science/
Read elsewhere that alpha amylase starts to denature at 153.

 

[Smellyglove]

Thanks!
As for pellet hops, I wonder if it's such a straightforward situation.
I've read that hops kilning is done around 150F, and amylase denatures around that temp. BYO article says that beta amylase can be completely destroyed in 5 minutes at 149F. https://byo.com/article/understanding-enzymes-homebrew-science/
Read elsewhere that alpha amylase starts to denature at 153.

I'd take those 5 minutes with a pinch of salt. I have a feeling we would all end up with way less attenuable wort if that was correct.

 

[Miraculix]

Thanks!
As for pellet hops, I wonder if it's such a straightforward situation.
I've read that hops kilning is done around 150F, and amylase denatures around that temp. BYO article says that beta amylase can be completely destroyed in 5 minutes at 149F. https://byo.com/article/understanding-enzymes-homebrew-science/
Read elsewhere that alpha amylase starts to denature at 153.

You have to differentiate between enzymes in solution and enzymes in a dry environment. The latter can survive much higher temperatures (see the kilning process of malt).

 

[day_trippr]

I think 150 is high. Iirc one of the professionals that visits the Hop Growing forum kilns at 130 to better preserve essential oils and reduce oxidation...

Cheers!

 

[specharka]

The conversion of residual dextrins to fermentable sugars by dry hopping, like mashing, is also highly temperature dependent. A great deal of commercial breweries “soft crash” their beers prior to dry hopping to arrest hop creep and avoid diacetyl production.

 

[isomerization]

“The refermentation of beer driven by dry-hopping was attributed to the low but persistent activities of several starch degrading enzymes present in Cascade hops including amyloglucosidase, α-amylase, β-amylase, and limit dextrinase.”

https://pubs.acs.org/doi/abs/10.1021/acs.jafc.8b03563

I don’t know about the temp stability, but it’s not just a single enzyme at play.