Infection! Help me find the cause

[H0PM0NSTER]

Hi all,

I'm on my 18th brew (kits with additions) and disaster has struck - not once but twice! I'm dreading a third occurrence, so trying to work out what could be the source of the infection.

It all started with a plum and liquorice Wherry (an attempt to clone Badger Ales Poachers Choice). All seemed to be going well until I added the fruit, which I did by racking the beer to a secondary FV after two weeks. I wanted to get a fresh plum taste rather than stewed fruit, so I didn't want to heat the plums. Instead, I stoned, chopped and mashed them - everything sprayed with Starsan (except the plums which were just very well washed and once mashed, were left overnight with two crushed campden tablets in an attempt to fend off any wild yeast).

A day after racking the Wherry onto the plums in the secondary, it was clear that all might not be quite right: A rather pungent egg / sulphury smell was coming from the FV which got so bad you could smell it from outside the spare room I use for brewing. However, apart from the wretched smell there was no obviously signs of an infection - no mold on the surface of the wort or anything floating in it. I had read that some yeast could give off sulphur smells, and these could be driven off by the carbon dioxide created during the fermentation. With this in mind, I let the wort sit on the fruit for ten days which was when I planned to bottle it. However, the smell and taste didn't improve - the beer no longer tasted like beer or fruit. It had a hot, acrid, eggy taste which was so horrible that it seemed a waste of time to bottle. Down the drain it went. :-(

At the time I was pretty sure that I must have introduced some nasties in with the fruit and vowed to boil everything in the future. The following two brews were fine (a Wilko Golden Ale kit with citra hops, and a Brewferm Ambiorix kit), but my latest brew, a Coopers Real Ale kit has suffered the same fate. The egg smell is less pronounced, but there is definitely a distinct aroma and taste. I've actually bottled this one just to see if it gets better or worse over time, but I'm not very hopeful.

So, what could be the source of both brews suffering very similar issues (perhaps the plums were innocent after all!?). Here are my suspects, but I'm hoping more experienced brewers may point out something I've not considered.

1. I used pale crystal malt in both brews. This was steeped in 65c water for 20mins before being strained through a santised seive and then added to the FV. Should I have boiled the water after straining out the malt? Could the malt have introduced an infection?

2. I added DME from the same bag for both brews. This was dissolved in the steeped water from the crystal malt. Could it be the DME?

3. Could it be the FV? I was very thorough to clean everything after the Wherry disaster and the FV sat for several days with a strong VWP solution in it, but could there be a yeast infection on a piece of my kit? If so, it's weird that I managed two brew without issues.

4. Was it an infection after all? Both brews were fermented at quite low temps which I've read can increase the chances of suphur smells during fermentation. Will I be pleasantly surprised by the Real Ale in a few weeks of conditioning and regret ditching the Wherry prematurely? (I seriously doubt it - the trial jar was pretty awful :sick:)

Any suggestions would be really appreciated. Cheers fellas.

 

[clibit]

1. Not boiling the wort from the crystal grains. Grain is a major source of wild yeast and this is the main reason why AG brewers boil their wort. Brewers actually use this as a way of introducing wild yeast to make soured beers, which is what you were on your way to achieving, in all probability. Souring requires some skill and judgement though. It may have turned out very drinkable, may not.

 

[DoctorMick]

1. Not boiling the wort from the crystal grains. Grain is a major source of wild yeast and this is the main reason why AG brewers boil their wort. Brewers actually use this as a way of introducing wild yeast to make soured beers, which is what you were on your way to achieving, in all probability. Souring requires some skill and judgement though. It may have turned out very drinkable, may not.

Wild yeasts are a bugger to get rid of as well I believe? I've seen a few things which say you should get a separate FV for doing sours and lambics because the yeast can affect future brews.

 

[clibit]

Yes but at the same time not to be terrified about. Follow a good regime and you will be fine. Don't use the same FVs obviously if you make beers with wild yeasts. I had a short spate of wild yeast infections but it hasn't returned. I spent some time in a brewery where you were not allowed to take fruit in the building for this reason. But I have fruit in my kitchen, where I brew. Everything introduced to your beer must be sterilised by boiling or using a sanitiser like Starsan, and that includes any grain or wort from grain. So you must boil any wort for at least 15 minutes.

 

[MyQul]

I cultured up a brakespear yeast from a bottle conditioned beer and it too had a very pronouced eggy/sulphurous/farty smell. So much so I only used it twice before the missus banned me from using it again.

I did a bit of research (googling) into whether it was supposed to be smelling like that. During the course of my research I found that these eggy smells are caused by either the yeast or bacterial infection, I think you had a bacterial infection as if it is the yeast producing it, then you are correct that the C02 drives it off (which is exactly what happened to my smelly yeast).

It's interesting that the following two brews were fine but the third wasn't. Sound's like you had a second infection rather than than the original infection not entireley disappearing - looks like its time to go OCD with the cleaning routine.

 

[clibit]

Yes, some yeasts do smell incredibly sulphury. I've done a Belgian ale once, and the smell freaked my kids out. But if you have steeped grains and added the liquid to the beer without boiling, you have added wild yeasts! Chances are it might have made a lovely sour beer!

 

[H0PM0NSTER]

Thanks for all the responses guys - really appreciated.
Sounds pretty conclusive that the steeped grains were to blame - especially as the two brew that have suffered this problem are the ones I added the steeped malt to.

I think I'll give the FV another soak in VWP just to be on the safe side, but I think my cleaning after the first incidence must have been pretty good which is why I didn't get any problems with the following brews until I re-introduced the wild yeast by steeping more malt and not boiling it!

I'll let the Coopers Real Ale that I've bottled condition and see if it matures into a drinkable sour beer. It will be interesting to see if the eggy taste and smell turns into something nicer.

When I brewed the Wherry I was pleasantly surprised that it hadn't stuck (as I've had no end of problems with this kit previously). Little did I know that it was a wild yeast infection eating up all the sugar and making up for awful Muntons yeast supplied with the kit!

 

[Twostage]

I cultured up a brakespear yeast from a bottle conditioned beer and it too had a very pronouced eggy/sulphurous/farty smell. So much so I only used it twice before the missus banned me from using it again.

I'll have to remember that one - 'It's not me it's the yeast love' :-D

 

[MyQul]

I'll have to remember that one - 'It's not me it's the yeast love' :-D

Will give you excuse if you don't have a dog;-)