Sweaty/onion Aroma - No Chill Ipa

[big78sam]

Something I have noticed in some of my No chilled IPAa is that the hop aroma and flavour is great for the first 2 months but then I start to get a sweaty/onion aroma, and to a lesser extent flavour, coming through. I would have expected the hop aroma/flavour to dissipate somewhat in the bottle but the sweaty/onion character is something different. I notice it and in the last Vicbrew a couple of the judges pointed it out as well. The beer if definitely drinkable still but I'd just like to eliminate this if I can.

I tend to notice it in some bottles more than others but this could be a serving temperature thing. I starsan the bottles pretty thoroughly and I've never had bottle infection troubles Has anyone else noticed something similar? Can anyone point to possible reasons behind this?

Here is a bit more info to my processes

Normal grain bill is base + 15 to 20% each of munich and Rye + a small amount of a light crystal. I have started to notice it since I began using Rye although this could be a coincidence.
Typical hop additions are American hops at 10 min, 5 min, flameout, cube hop and then sometimes a hop tea and/or dry hop
I haven't been using calcium sulphate but have just purchased some this week so will now do so in hoppier beers. I usually just use a bit of calcium chloride to get my calcium levels to the minimum acceptable level
I BIAB in an urn and no chill
I typically use WY1272 and ferment at around 18 degrees.

 

[Thirsty Boy]

Ipas are at their best inside that period anyway, i would expect them to drop away, have the more delicate and floral aromas dissapate and for the other aromas to come through more.

Certain hops have in various amounts, onion/garlic type characteristics that might be coming out once the more pleasant flavours drop off with time. Simcoe and summit are two that i have seen talked about.

Does it have anything to do with no chill?? Who knows, it might, so the only way to tell is to re-brew the same recipes, in the same way and age them for the same amount of time... But having chilled the wort rapidly.

I suspect that the best answer is to simply drink your IPAs faster when they are at their best anyhow.

 

[glaab]

GDay Sam, I've noticed some batches of Amarillo seem to have a funky smell so it might just be that if you've been using it. The first thing that came to mind though was a brett infection which smells to me like gorgonzola but "sweaty/ onion" is probly a good description. Pretty sure I had it in a keg once, it only appeared after about 6 weeks. If youre reusing the same yeast maybe try a new pack, maybe you need a new cube. Cheers

 

[sam]

Certain hops have in various amounts, onion/garlic type characteristics that might be coming out once the more pleasant flavours drop off with time. Simcoe and summit are two that i have seen talked about.

CTZ (Columbus, Tomahawk & Zeus) also have that onion/garlic thing going on. Echoing Thistys' thoughts - drink em quick.