Bad fermentation smells

[Ben Matthews]

Hey peeps. I started a new batch of Belgium blonde a couple weeks back. It's basically
3kg pilsner malt
100g wheat
100g munich
350g sugar
25g hallertau at 60 mins.
5g saaz at 5 mins

Used a new yeast WY yeast 3522 Belgian Ardennes and for the first time some wy yeast nutrient blend.

All has gone well hit target og of 1.067

Fermentation took off. Yeast went bonkers and nearly blew the lid off. Managed to contain it with a few blow off tube changes. Smelled amazing yeasty and fruity as you'd expect. Then as the Krause dropped down a bit the smell changes. I couldn't put my finger on it but it was a little peanut buttery. This increased and near the week and a half to two week mark it started smelling like peanut butter mixed with urea. Quite weird and rank. I assumed it had got infected so took a sample. The sample smelled and tasted as normal. Quite darn nice and my gravity was at 1.017 so nearly there but going to leave another week and see if it goes lower. Lids been back on and a small amount of airlock activity since and more of the smell.

I'm sure it'll all turn out fine but just wondered if anyone had experienced this with this yeast or that nutrient blend. Is it gonna be safe to drink?

Fermentation started at 18 degrees and was increased up to 20 over first week and 22 by end of second week.

Thanks peeps.

 

[QED]

I've used that yeast before and i think it's pretty common, both the massive initial blow off and the smell. I didn't have the smell however i (accidentally but maybe luckily) started my fermentation at about 16c and slowly increased. I think the commonality in people who experience the smell is the fermentation temperature being too high. Just my guess though!

 

[An Ankoù]

Thanks. I'll avoid that yeast. There are plenty of "wholesome" smelling yeasts knocking around. Used Danstar ESB in a mild and it stank of drains. Nearly threw it away, but the taint is subsiding as it conditions.

 

[Ben Matthews]

It's meant to be a really tasty yeast. If la chouffe where it comes from is anything to go by it should be good. The sample tasted great. It may have even been 17 degrees I started at so I'm sure it's not temperature. I held it cool until after high Krause to help contain the beast. I've heard the wyeast nutrient may have urea in so wondered if it might be coming from that?

 

[QED]

Just had a google, reports of some people racking it for a week or so which got rid of the smell and others saying it disappeared after conditioning...ans some saying it stayed!

https://www.homebrewtalk.com/threads/peanut-off-flavor-why.446115/https://www.homebrewtalk.com/threads/sulfur-smell-with-wyeast-3522.249907/

 

[Ben Matthews]

Ah top googling there bud. I couldn't find anything on that.

 

[Ben Matthews]

Definitely has a urea smell to it but just out the airlock. The hydrometer trial jar sample.smelled normal. Hopefully with another week conditioning it'll be good to bottle.

 

[strange-steve]

Wy3522 is a fantastic yeast, I love it in a Belgian pale. I don't recall any unusual smells, but then my fermentation fridge is in the shed and I don't really check on it often. There are often wierd and funky fermentation smells from various yeasts, doesn't necessarily transfer to the finished product though. Give it time in the FV and it should clean up.

 

[johncrobinson]

Just had a taste of urea as an experiment (The chemical nothing kinky)
I think steve-strange is correct allow time for the yeast to clean up after itself.

 

[QED]

Just had a taste of urea as an experiment

Did you just drink AdBlue??

 

[Ben Matthews]

Wow good effort there. Where did you get urea the chemical? Yea I think just leaving it will be all is needed. Patience is the key.

I did see in my notes I may have underpitched as my two consequetive starters both went nuts and I lost a fair bit of yeast through blow off so it could all be due to that.

 

[CD]

The worst smelling fermentation I've had is when I tried 'Nottingham' yeast (which comes from Denmark I think), rotten egg smell. Strangely the beer was fine, and the smell went after a while. Never used it since.

 

[Edison]

Hi Ben,

Did you make a starter up for the yeast or just pitch the pack straight in? Any oxygen added? Did you add the nutrient to the boil or in the FV?

Im currently drinking a Belgian Blonde made using this yeast and it tasted great. Nice peppery spice and slight bubblegum/banana but nothing ‘in your face’, very enjoyable. Have the yeast stored for reusing again later, it’s good stuff!

If everything was kept super clean it shouldn’t be an infection so should fade as the yeast cleans up after itself post fermentation. Your temperatures look fine to me.

 

[Ben Matthews]

Hi Ben,

Did you make a starter up for the yeast or just pitch the pack straight in? Any oxygen added? Did you add the nutrient to the boil or in the FV?

Im currently drinking a Belgian Blonde made using this yeast and it tasted great. Nice peppery spice and slight bubblegum/banana but nothing ‘in your face’, very enjoyable. Have the yeast stored for reusing again later, it’s good stuff!

If everything was kept super clean it shouldn’t be an infection so should fade as the yeast cleans up after itself post fermentation. Your temperatures look fine to me.

Hi Edison. Yes I made a starter. 2 steps but may have lost a fair bit of yeast as they went nuts and blew off a lot. Wyeast nutrient was added 10 mind from end of boil. Aerated it well but not pure oxygen. Weird? Like I say the sample tasted and smelled fine. Seems to be just gas from the yeast that smells? I'm hoping this batch turns out good and am hopeful it still will be. The wort was the best ive made and the fermentation temp control was really good and my target og bang on so hoping it'll be my best batch yet. I'll keep it updated. I've kept some of the starter back for future use. I make a lot of Belgian blonde. Found wlp500 was good but a bit too fruity for my blondes. Tasted like it would be better in a dubbel.

 

[Edison]

Everything sounds pretty much spot on then, I’m sure it will come out great. Some yeast strains produce some odd smells during fermentation, some lager yeasts smell foul of rotten eggs, it as long as they’re given enough time to finish off in the FV after hitting FG the off smell completely goes.

I followed this recipe almost exactly (apart from the temperature overrunning a bit high initially):

https://beerandbrewing.com/make-your-best-belgian-blond-ale/
Thinking I may try this yeast in a strong dubbel/dark trippel e.g. Gulden Draak.

 

[Ben Matthews]

I read that recipe actually and added the saaz at 5 mins as that's all I had on hand and some Munich. Sounds really good. What's it like with the Marris otter. I didn't have any at the time but would like to have a go with that grist in the future if it's good. Also didn't have any victory. My recipe is loosely based on Jamils.

 

[Edison]

MO is my go-to pale base for pretty much everything, other than lager or something more specialised. I‘ve used MO extra pale for anything I want really low colour or light bodied.

 

[Ben Matthews]

Just found a couple things on urea production in yeast and is a slightly worrying read. Am starting to think I might have to just dump it and start over?

https://academic.oup.com/femsyr/article/17/7/fox072/4411803
https://en.wikipedia.org/wiki/Ethyl_carbamate

 

[Edison]

I wouldn’t like to say, I’ve not experienced those smells myself. My gut would say stick with it, have patience, make a decision when it’s had time to fully condition, don’t do anything rash!

Hopefully someone with more experience than me will chime in.

 

[Ben Matthews]

Yea there's no harm in hanging on while i decide. Still a little airlock activity so I'll check it again at the weekend and maybe pull another sample.