Off-flavors From Unviable/old/under Pitched Yeast

[The Scientist]

Hi all,

I've had an earthy / herbal / dirty flavour come through in a could of my brews over the last few months and I'm not sure what is causing this.

I've considered that it is possibly from using unviable / old / under pitched yeast, but have not been able to find any info to back this up. I have been creating a starter for each brew and I taste all starters before pitching but have not picked up this flavour at this stage.

What flavours are created from a yeast which is under stress?

What can produce earthy / herbal / dirty flavours?

Any info would be good.

Cheers,

TS

 

[Adamt]

Earthy and herbal can be hop notes.. Not so much dirty though.

Could it be described as "vegemite"? That can happen when you leave the beer in primary for too long.

 

[white.grant]

Hi there TS

Stressed yeast can do a lot of things, first off if they're unviable, they won't ferment so well, so you would have seen issues during the fermentation - slow start of fermentation, higher than anticipated FG, poor flocculation and a change in the flavour profile of the particular yeast amongst other things. A weak yeast could also be out-competed by some other wild yeast hanging around in your fermentation area.

I guess it all depends, how old are the yeast? what kind are they and how have they been stored


cheers

grant

 

[Darren]

Fuggles and goldings are also known as "dirt hops" so that could be the cause

cheers

Darren

 

[therook]

Funny you should bring this topic up TS, i was telling TDA how my Occy had the same dirty earthy taste as you noted at around 1.016, i upped the temp to 18c for 2 days and it went...no idea if its related to your problems or not...

Rook

 

[Thirsty Boy]

in taste training - for ages I would be spouting stuff about earthy, musty, leaf litter ... that sort of stuff. Everyone else would be saying nutty. It took a while to learn.

A light hand with roast barley can give you nutty - which its possible to interpret as earthy/musty (for me anyway) - and that could be layered with an earthy herbal type of hop character.

Underpitching would be more likely to give you overly estery flavours, fusel alcohols and perhaps acetylaldehyde or diacetyl in combination with underattenuation

 

[The Scientist]

It's strange, cuz the brew finnished at 1.010 which is what I was aiming at and it hit final gavity within 5 days. Also there was no real long lag time in the krazen being formed, so I thought things were going well.

With regards to hops giving a dirty flavour, I used 10g of POR with 10min remaining in the boil and they are known for imparting some herbal flavour but I doubt that this is what I'm experiancing though.

The yeast was a re-cultured coopers yeast which was second generation and no more than 3 months old. The first gen turned out excelent and was such a fantastic yeast I had intended to brew with it more frequently.

I don't believe it could be a recipe issue but the brew was as follows:

Aust Pale Ale - Oct 09

A ProMash Recipe Report

Recipe Specifics
----------------

Batch Size (L): 25.00 Wort Size (L): 25.00
Total Grain (kg): 4.65
Anticipated OG: 1.044 Plato: 10.89
Anticipated SRM: 7.6
Anticipated IBU: 31.5
Brewhouse Efficiency: 75 %
Wort Boil Time: 60 Minutes

Grain/Extract/Sugar

% Amount Name Origin Potential SRM
-----------------------------------------------------------------------------
53.8 2.50 kg. Weyermann Pilsner Germany 1.038 2
21.5 1.00 kg. TF Maris Otter Pale Ale Malt UK 1.037 3
5.4 0.25 kg. Crystal 75L Great Britian 1.034 75
10.8 0.50 kg. JWM Light Munich Australia 1.038 10
8.6 0.40 kg. Wheat Malt America 1.038 2

Hops

Amount Name Form Alpha IBU Boil Time
-----------------------------------------------------------------------------
13.00 g. Warrior Pellet 15.80 24.3 First WH
15.00 g. Styrian Goldings Pellet 4.75 4.8 30 min.
10.00 g. Pride of Ringwood Whole 10.00 2.4 10 min.
10.00 g. Chinook Pellet 11.00 0.0 0 min.


Is it possible this off flavour could be from an infection? Has anyone ever had somthing like this before?

Cheers,

TS

 

[Maxt]

Stressed yeast throw esters. It's one way to get good banana in a wheat. You under aerate, and the yeast responds with more esters.
I woudn't imagine you would get earthy though. Is the flavour getting stronger?

 

[The Scientist]

Is the flavour getting stronger?

Not really, fermentation has finnished and the flavour is the same now as it was a couple of days ago. I've crash chilled it to see if that makes a difference but its still the same. It's drinkable but I wouldn't say it was pleasant

 

[The Scientist]

Ok so I dumped the dirty Aust Pale and did some major cleaning, Starsand and boiled everything.

Got a starter going with WLP500 for my Belgian Tripple, at each step up no krazen formed with the starter yet fermentation was complete. So I pitched the yeast and fermentation started within 6 hours.

I have given it a taste this arvo and that fcukin flavour is back :angry:

So where the hell is it coming from I don't detect it in my staters or my wort and my fermenter has to be clean, so WTF!!!



TS

 

[Adamt]

Where are you storing your fermenter? Is it properly sealed (airlock or otherwise)? What other products are you using to clean? Do you ever switch up your cleaning products?

 

[The Scientist]

Where are you storing your fermenter? Is it properly sealed (airlock or otherwise)? What other products are you using to clean? Do you ever switch up your cleaning products?

Hi Adamt,

I use Nappysan to scrub the larger filth out then boiling water and finnish with either Starsan or Saniclean. Always clean the fermenter out just before adding the wort. No airlock as such just a valve to vent any Co2.

I've only been using 5 star cleaners for a couple of months but used to use bleach before this.

 

[clean brewer]

Fermenter Taps/Thread>? :unsure: ????????

CB

 

[Adamt]

Hi Adamt,

I use Nappysan to scrub the larger filth out then boiling water and finnish with either Starsan or Saniclean. Always clean the fermenter out just before adding the wort. No airlock as such just a valve to vent any Co2.

I've only been using 5 star cleaners for a couple of months but used to use bleach before this.

If you are scrubbing with a scourer/something hard that scrtches the inside of your fermenter, you'll make an almost uncleanable cavity for any old bug to hide in. Also, maybe it's time to do a good bleaching, and clean your taps and threads as mentioned above.

 

[Screwtop]

A long shot, as you've been around a while I'm sure you would have used styrian goldings before, could it be them and have you used them in the tripple?????

Just a thought

Screwy

 

[Adamt]

Another morning thought... If you're in BABBS or another brew club, or know some other nearby brewers, they may be able to better identify the problem with a tasting.

 

[The Scientist]

Another morning thought... If you're in BABBS or another brew club, or know some other nearby brewers, they may be able to better identify the problem with a tasting.

Righty O,

BABBs Boys look out at the next meet for a game of name that infection :icon_vomit:

Cheers for the idea Adamt :icon_cheers:

TS

 

[Andyd]

Another morning thought... If you're in BABBS or another brew club, or know some other nearby brewers, they may be able to better identify the problem with a tasting.

+! for Adamt's advice - there's no better way to get advice than to get together with a group of fellow brewers, hopefully with a few really experienced hands. That's one of the greatest things about a brewing club.

Andy