Mouldy smell

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saintmark

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