Infection

[manga]

I am brewing an Australian Old style beer using Safale S-04 yeast.
Brewing was as per normal. Here is my log:

Day 7: Dry hopped. Tasted a sample of the beer and it was roasty.
Day 14: Last check before trouble. Some small bubbles still rising in the fermenter, gravity 1.014, leaving it a few days to ferment out.
Day 20: Opened the lid and discovered large (2-3cm diameter) bubbles amid a thin white film. The smell was still like before, roasty. No sour or off smells.

It definitely looks like an infection to me.
Does anyone know what it is and how it may have started ?

 

[MHB]

Could be lots of things, but it looks like Lacto. Those big greasy looking bubbles are pretty typical.
As for where it comes from its in the air, but mostly on you, particularly in spit.
If you open the lid on a fermenter (I try to avoid doing so), keep your face out, a flake of skin is enough, don't stick your nose over the edge to take a sniff, don't drop an eyelash and most important don't talk, you will get micro droplets of infected spit in your beer. Really I think brewers are the biggest danger to beer.

Basic good brewing practice helps a lot to.
Really good cleaning and sanitising of all equipment being a given.
If a beer takes 14 days to reach FG you have under pitched, the amount of beer you have, the gravity and the temperature are all part of the equation. A good pitch wont stop infections but will reduce the chances.
After 14 days there is measurable harm being done to your beer mostly by yeast autolysis, that will affect the flavour and the release of Protease A which will degrade the head and can make the beer very thin tasting.

Things that supress bacteria include, de-Oxygenation of the wort by yeast - more yeast will suck up the O2 faster. Lower temperatures. Alcohol, again a faster start gets alcohol into the wort faster. Hops - yes they do contain some antibacterials. Pressure, get the brew done and get the beer packaged and under pressure helps.

No matter how careful you are you will always get some infections, some bacteria and yeasts have adapted to the brewing environment, the noted Spoilage Microorganisms (Lactobacillus, Pediococcus, Brettanomyces and Acetobacter (Vinegar bacteria)) are all an ongoing battle, bit like the one we wage against rats, I'm far from sure we are winning either, maybe a draw is the best we can hope for.
Mark

PS - blitzkrieg that fermenter! total over the top sanitation or the bugs will be back.
M

 

[manga]

Thanks a lot MHB. I have made 60+ batches and never had an infection.
My last 5 batches have been dry hopped, never dry hopped before those. I have read that dry hopping rarely results in contamination.
I do open the lid slightly ajar to take a peek, so I must have breathed into it.
I did not make a yeast starter, just spinkled the dry yeast into the aerated wort. I'll make a starter in future to get the wort brewing asap.
With the infection possibly being Lactobacillus, these are bacteria in our bodies and yoghurt. Would it be safe to consume this beer ? Not that I want to, just curious.

 

[MHB]

Safe yes - pleasant probably not. There are no known pathogens that can survive in beer.

I'm going to disagree with you big time on the infection, if you have made 60+ batches in truth they were likely all infected (defined as something other than the intended yeast). Point is that most bacteria/wild yeast are supressed by brewing conditions, to our advantage is the fact that most of them are benign at low concentrations.

Standard practice in a commercial setting is to take 100mL of beer, centrifuge it down so all the yeast and any bacteria are clumped at the bottom or concentrated by filtration. This little pellet of living things is then spread on special agar plates that wont support yeast so only other things grow.
Have read of an experiment done with home brew where they had to omit the concentration step because they couldn't count all the colonies (too many and they start to mix or overlap) Have a read.
Point is most beer is infected, it usually doesn't matter but occasionally you will get a stinker!
Do the best you can.
Mark

 

[manga]

I'm going to disagree with you big time on the infection, if you have made 60+ batches in truth they were likely all infected

Probably, in minute quantities but not like as in my photos. This was a first ! All my beers turned out well, no bacterial scum floating on top. Thanks for all your help again.

 

[Nick667]

Great info here. Thanks MHB

 

[Fro-Daddy]

Pressure, get the brew done and get the beer packaged and under pressure helps.

A little OT, but does this apply when pressure fermenting as well?

 

[MHB]

Does what apply?
The need for hygiene, the right pitch rate, temperature control... Yes! they all matter
Pressure when the beer is mature will help supress bacterial growth, during the ferment I doubt it applies.
Pressure fermentation might make it a bit harder or people to lift the lid and let bugs in, probably the only good thing about pressure fermentation I'm sure of. (Ok I'm not a fan)
Mark

 

[Fro-Daddy]

Sorry, should have been more clear. I was asking if when pressure fermenting, does the pressure at this time help prevent an infection.
Looks like you answered it though.

I am only doing low pressure, ~3psi/20kPa, to make life easier with a closed transfer when it's ready.

 

[Paddy Melon]

Safe yes - pleasant probably not. There are no known pathogens that can survive in beer.

I'm going to disagree with you big time on the infection, if you have made 60+ batches in truth they were likely all infected (defined as something other than the intended yeast). Point is that most bacteria/wild yeast are supressed by brewing conditions, to our advantage is the fact that most of them are benign at low concentrations.

Standard practice in a commercial setting is to take 100mL of beer, centrifuge it down so all the yeast and any bacteria are clumped at the bottom or concentrated by filtration. This little pellet of living things is then spread on special agar plates that wont support yeast so only other things grow.
Have read of an experiment done with home brew where they had to omit the concentration step because they couldn't count all the colonies (too many and they start to mix or overlap) Have a read.
Point is most beer is infected, it usually doesn't matter but occasionally you will get a stinker!
Do the best you can.
Mark

Hi M, I don't often write on here but I read as much as I can and I just had to say how much I appreciate your contributions. They have certainly been informative for me and have helped me with issues I didn't even know I had or would face. One day I hope to be able to contribute something significant.
P

 

[peterlonz]

One point - I am far from convinced that making a starter is in any way likely to reduce the potential for infection.
I'd suggest: just use two yeast sachets of your favoured yeast.
I have used SO4 & SO5, both are relatively slow to get started when pitched directly into the wort.
My preference now is one sachet SO4 & one sachet of (Coopers general purpose yeast I guess).
I also practice saving the dregs of my last brew to start the next, but only once. By dregs I mean unwashed mix of yeast & whatever by product remain from fermentation, stored at around 2.2 C & gently warmed to room temp before pitching.
I also think there is probably some small level of infection in most home brewed beer, the key is to be watchful ensure the infection remains below detectable levels by taste.