Degradation of Hop Oils

[ncbrewer]

For several years I've been using hops that weren't vacuum sealed or nitrogen flushed by the supplier, but were stored refregerated - with generally good results. Even my APAs, with a hop stand for aroma and flavor, come out good. But the last three of my ESBs (with Willamette or Fuggle for aroma) were bad. With some of these, hops were straight out of a sealed foil bag in the freezer. There was no hop flavor or aroma - just an off smell and taste. And this isn't from aroma fading with age - there was no aroma even in the fermenter sample after just 15 days in the fermenter. The closest I can describe is stale. I don't get what I'd call a cheesy smell.

My understanding is that the oils are more susceptible to staling than the alpha acids. My theory is that the speed of degradation varies greatly depending on which oils are present. Simcoe and Mosaic (used in my APAs) keep pretty well, but Willamette and Fuggle (used in my ESBs) don't keep well. Based in this idea, I'm planning to use only vacuum sealed or nitrogen flushed hops for ESBs, but remain flexible with the other hops.

Any opinions about my hop storage theory?

 

[cswis86]

What supplier are you getting them from? I've never seen hops packaged that weren't flushed or vacuum sealed. I do know that the aromas of Willamette and Fuggles are pretty subtle compared to Simcoe and Mosaic so depending on how much you used it could be hard to detect much aroma.

 

[Weezy]

Well it looks like you're comparing high alpha/ low cohimulone hops to low alpha/ high cihimulone varietals. The harsher, resiny, dank character that you get out of the former i could see being perceived as surviving aging better than the later but I'm guessing that it's just perception. Test it. Preserve simcoe and Willamette vacuum packed in the freezer and some much less carefully and dry hop with each only. Put one pellet of each in a bottle of pale bet with little boil hops.

 

[mredge73]

Alpha degrading is different than staling.
You should try this method if you are getting stale hops:
https://www.homebrewtalk.com/cheap-and-easy-hop-storage.html

I buy hops by the lb and have some still in the freezer from 2010. Once I open the flushed bag, I then put them in glass mason jars and vacuum out as much air as possible before putting them back in the freezer.

 

[ncbrewer]

What supplier are you getting them from? I've never seen hops packaged that weren't flushed or vacuum sealed. I do know that the aromas of Willamette and Fuggles are pretty subtle compared to Simcoe and Mosaic so depending on how much you used it could be hard to detect much aroma.

I've been getting the hops from Williams Brewing. They have just started getting some hops available that are nitrogen flushed, but only a few varieties, and not what I would like for an ESB.

Yes, Willamette and Fuggle have a subtle aroma, but this is more than low aroma - it's unpleasant. Maybe like a sweaty shoe.

 

[IslandLizard]

...But the last three of my ESBs (with Willamette or Fuggle for aroma) were bad. With some of these, hops were straight out of a sealed foil bag in the freezer. There was no hop flavor or aroma - just an off smell and taste. And this isn't from aroma fading with age - there was no aroma even in the fermenter sample after just 15 days in the fermenter. The closest I can describe is stale. I don't get what I'd call a cheesy smell...

[In red above]
Did you get those hops packaged like that? I'd take that up with Williams. If they had no aroma, something happened. Maybe they were from an old batch.

Many LHBS type outfits don't freeze their hops, they're in a display fridge. A year in a fridge will have degraded them. Hop Storage Index (HSI) of a hop is dependent on the variety, and IIRC, the index is based on refrigerated storage, not frozen. AA degradation seems to be the main issue, flavor and aroma far less. Here's a short thesis on hop stability.

Maybe try another supplier? YakimaValleyHops or HopsDirect. That's where I've been getting the majority of my hops from, with no issues at all. The former sells smaller quantities than whole pounds as well as other HB supplies.

 

[ncbrewer]

To answer some questions:
> Weezy: See my description of a sweaty shoe - not just loss of aroma.
> Mredge73: I like the storage system - might try it.
> IslandLizard: I haven't had any problem with bitterness - just the flavor and aroma, and just with Willamette and Fuggle. A Beersmith newsletter stated “aromatic hop oils are the most susceptible to aging”, and some other info I have (a little dated) says that little research has been done on rates of aromatic oil loss on various varieties.

I feel that the fix for this is straightforward. The non vacuum sealed and non nitrogen flushed hops aren't best practice. Since I've seen an intermittent problem, I'll try using hops that are vacuum sealed or flushed (maybe Yakima Valley Hops). But my selective hop degradation theory is a little shaky, at best. Still, nobody has come right out and said I'm completely crazy. I'll see how it works out. Thanks much for the responses.