A little concerned.

[Kyle_T]

As the title suggests I am a little concerned I may of messed something up with my Coopers Ale, I kegged it on Monday and today I took a small sample to see how she had turned out, the colour and taste are magnificent, but there seems to be a smell of what I can only describe as a banana scent and it seems flat, upon tasting there is certainly a fizz in the liquid but there is virtually no head on it at all. And no pressure has built up inside the barrel, any thoughts? Would be a shame to have to bin it.

 

[rpt]

You need patience. Only 3 days in the keg is no time to build up much pressure. The beer itself will also need more time to mature.

And if it tastes magnificent why would you want to even consider binning it?

 

[joe1002]

Your problem sounds yeast related to me.

What was your fermentation temperature and did it fluctuate much? What yeast did you use and how did you pitch it?

Banana and pear flavours are produced by an ester called Isoamyl Acetate so I understand.

 

[PD]

which is present in all beers. It plays an important role in the overall flavour and taste. Concentrations of Isoamyl Acetate vary considerably from beer to beer. Major flavour impact character of some beers, eg wheat beer.

according to wikipedia...

 

[Sean_Mc]

Way to early, but I like it :lol:

Give it a week in the warm then a week in the cool :thumb:

 

[Kyle_T]

RPT - I know it's only 3 days but the bitter I did nearly blew the barrel apart in 3 days, yet this is nearly as flat as a car tyre on a council estate.

Joey - the temp was a between 20 and 22 degrees day and night. The yeast was just the standard yeast supplied with the kit and it was sprinkled on top, left to right to be exact after taking a hydrometer reading after mixing everything together.

 

[joe1002]

Guess who has been reading the 'Yeast' book :whistle:

 

[Kyle_T]

Theres a yeast book?

 

[just_steve]

I'm not so sure it's a yeast problem. This is me speaking as a chemist, not a brewer. Your fermentation temperature sounds fine. I think you've allowed a bit too much oxidation in your keg. 'Banana oil' as I know it, isoamyl acetate, is a chemical I've synthesised at university - smells lovely, as do all esters. Esters are normally made by combining an alcohol with a carboxylic acid. In this case, isoamyl alcohol and acetic acid (vinegar). We all know that vinegar is an oxidation product of ethyl alcohol. I'd guess that this is what's happened to your beer. Supporting this theory is that your keg isn't pressurised: maybe there is a leak in your seal that's allowing excess pressure to escape, AND introducing external oxygen to oxidise your ethyl alcohol.

 

[rpt]

I was going to suggest that perhaps your keg isn't gas tight and chemist Steve has given an even better explanation why that could be the case. Also be aware that different brews might behave differently, so although the bitter only took 3 days this ale might take 2 weeks to fully carbonate.

 

[JohnStone]

Step away from the keg Kyle.....................................

Give it some more time and double check and make sure your seals are nice and tight :thumb:

 

[Kyle_T]

Going by the banana oil theory, I have given the keg a thorough look over and I have discovered one of the rubber washers on the outside of the cap has split. For f**k sake. Is there anyway of getting rid of the smell after making it air tight?

 

[rpt]

I've read it will disappear in time. So don't panic!

 

[Kyle_T]

That's not so bad then, looks like I'll have to wait until Saturday to pick up a new valve, reckon it will be alright until then?

 

[JohnStone]

Would giving the keg a shot of co2 help or switching the leaking valve cap for a blanking cap until the damaged rubber can be replaced?

Colchester Homebrew supplies does replacement valve rubbers £0.65

 

[joe1002]

Theres a yeast book?

Yep, and a review here

 

[Kyle_T]

Just an update guys, Went to the local homebrew shop at the weekend, bought a new valve seal and a new valve, replaced both on the barrel, gave it a blast of CO2, let it drain slowly and I can happily say she is carbonating rather well and pressure is building. Thanks for the tips.