Mouldy smell

[saintmark]

Hi,
After my brew had been in the bucket for about a week I noticed that it had stopped fermenting as it had an initial bubbling phase and then seemed to stop. I took the lid off and gave it a stir and this seemed to get it going again but now I'm getting a mouldy smell from the bubbler. Does this mean the batch has spoiled?

 

[chewie]

Hi,
After my brew had been in the bucket for about a week I noticed that it had stopped fermenting as it had an initial bubbling phase and then seemed to stop. I took the lid off and gave it a stir and this seemed to get it going again but now I'm getting a mouldy smell from the bubbler. Does this mean the batch has spoiled?

"After my brew had been in the bucket for about a week I noticed that it had stopped fermenting as it had an initial bubbling phase and then seemed to stop"

This is when you should have first used a hydrometer to check exactly what point your brew was at, airlock activity or lack of is no guarantee of a fermentation being completed.


"I took the lid off and gave it a stir and this seemed to get it going again but now I'm getting a mouldy smell from the bubbler. Does this mean the batch has spoiled?"

When new, the first instinct everyone has is to remove the lid and take a look, whilst it isn't the worst thing you can do it is not recommended and should only be done to take a hydrometer reading, if the brew should prove to be stuck via a hydrometer then ask for advice before stirring it. As temps drop lack of heat is more likely to play a part in something failing to ferment out, failing that pitching a better yeast if this was a beer kit usually works. If the batch is spoiled you will have either something foreign growing on it or very unpalatable tastes which will worsen.

 

[saintmark]

There's nothing growing on it but I do have yellow bits floating in it. It just smells like damp. After opening the lid and re-fitting the mould smell does seem to go.

 

[Saisonator]

Damp is a smell that should not be present.

 

[crowcrow]

Have you tasted it?

 

[TiddlyWin]

A little research I found this.

Off Flavour: TCA

Chemical Name: 2,4,6-trichloroanisole

How to Identify: This one smells like mould, corked wine or a damp cellar. We all felt it was really like walking down into Franklin and Kim’s (impressive) beer cellar or sniffing the cork from a wine bottle.

What it is: TCA is a chemical created by mould which consumes chlorinated phenols and metabolises them and it can be detected by humans at extremely low levels.

How it is caused: Generally TCA is caused when beer is fermenting somewhere that is damp or where the grain has developed mould in storage but TCA is capable of migrating through most semi-porous packaging and thus cross contamination can occur across several areas of beer production, from raw materials to final packaging.


http://www.belgiansmaak.com/off-flavours-in-beer-off-flavours/

How accurate it is, is up to you.

 

[Clint]

Leave it another week.

 

[saintmark]

It's not got any worse and there's nothing growing in it. We shall see when I bottle it next week.

 

[saintmark]

Finally decided to bottle it. Noticed a very sweet smell and taste almost liable a cider vinegar. I'm pretty sure it's a bust as some of the bottles instantly grew mould and it's in them and the ones that didn't had a mist on top like an oil slick. I'll give it a couple of weeks and see how they go but I'm not hopeful.

 

[Steved53]

Finally decided to bottle it. Noticed a very sweet smell and taste almost liable a cider vinegar. I'm pretty sure it's a bust as some of the bottles instantly grew mould and it's in them and the ones that didn't had a mist on top like an oil slick. I'll give it a couple of weeks and see how they go but I'm not hopeful.

Methinks you have a deep clean session in your near future!