Beer contamination

[Mark Farrall]

Couldn't find iodophor in the Netherlands, so have chosen peroxyacetic acid. Hopefully, it will do the job as well

I've posted this in another thread recently, so you may have already seen this. I found this an interesting podcast on a paper that included some experiments on using an acid based sanitiser. In case you want more background:

Podcast - https://thebrulab.libsyn.com/episode-016-wild-yeast-contaminations-w-ronja-eerikinen
Paper - https://www.theseus.fi/bitstream/handle/10024/348696/Assessing Contamination Risk of Non-Conventional Yeast in Breweries.Ronja Eerikäinen.pdf?sequence=2

 

[Mark Farrall]

Correct, I also suspect transfer equipment + coldside (primary fermenter). I'm using a counterflow chiller (parallel plate chiller has been removed the first from the system, but it didn't help :-( ).
Through the valve setup I can circulate hot wort through the counterflow chiller during boiling and only what remains on the cold part is the silicon tube to the fermentor.
I removed the oxidization stone and oxidize wort by splashing (not the best but I wanted to simplify the system as much as possible).
silicon tube is sanitized by Star San + the whole fermentor is sanitized by star san + additional alcohol sanitization just before use.

The taste becomes sour acetic, a lot of small bubbles and the foam retention is almost nihil. Tastes and smells a bit like an apple cider.
I have a suspicion that it becomes stronger when aerated a bit (at bottling)
Couldn't find anything strange on the surface of the beer

Most acetobacter love oxygen, so the increase in flavour with oxygen and the taste may point to that. I do love a few beers with a healthy dose of flavour from acetobacter, especially from Brouwerij Verhaeghe to the south of you. Though I do understand that I'm in a minority there. Not sure what's involved in killing it, though I've seen a lot of people very worried about it. Not sure if that's the taste or the difficulty of killing it.

Your silicon tubing can be pasteurised in hot water (or even boiled depending on the tubing), leaving the fermenter. Is it a Brewtools fermenter? If it is, I suppose you could use the brew system to generate boiling water to pasteurise/disinfect everything (if you haven't tried that already). If it's plastic have you checked for scratches inside the fermenter?

Probably the wrong time to ask, but how have you found the Brewtools kit? It looks very flexible. Maybe too flexible for my simple mind.

 

[Asimi]

-less likely but do you know the ph of your mash? any chance an acidulated malt got mixed up in ingredients or too much acid used?

Yes, I measure pH during my brew - pH ~ 5.4-5.6 for my beers, I don't expect it to be a problem. I also changed different yeasts and used just a new yeast packs... No difference

 

[Asimi]

Most acetobacter love oxygen, so the increase in flavour with oxygen and the taste may point to that. I do love a few beers with a healthy dose of flavour from acetobacter, especially from Brouwerij Verhaeghe to the south of you. Though I do understand that I'm in a minority there. Not sure what's involved in killing it, though I've seen a lot of people very worried about it. Not sure if that's the taste or the difficulty of killing it.

Your silicon tubing can be pasteurised in hot water (or even boiled depending on the tubing), leaving the fermenter. Is it a Brewtools fermenter? If it is, I suppose you could use the brew system to generate boiling water to pasteurise/disinfect everything (if you haven't tried that already). If it's plastic have you checked for scratches inside the fermenter?

Probably the wrong time to ask, but how have you found the Brewtools kit? It looks very flexible. Maybe too flexible for my simple mind.

Indeed, from what I have read (from PALMER to "Brewing Microbiology" by Priest and Campbell) it looks like acetobacter. The question is how to get rid of it

I'm using Brewtools brew system and SS Brewtech Unitanks as fermentors.
WHat do you call "Brewtools kit"? Thier proposed multi-valve setups? I'm using my own 5-valve setup together with HLT and like it a lot.

One drawback that I have found is counterflow chiller - is too weak for 150L system, I don't want to use plate chiller (because of the reasons described above), so might go for the second counterflow chiller. Ideally I want to have nearly no delay between flame off and transferring to the fermentor

 

[Mark Farrall]

Unless the infection has formed a biofilm 15 minutes of 80C water should kill anything. Could you set up a recirculation between the fermenter and the brew system, get the water to 80C and set it recirculating for a while?

If that doesn't kill it I'd start to think there's some small space where a biofilm has formed. From what I've heard the secret to killing those is force and turbulence to get microbes to break up in to smaller and smaller groups so that they eventually die. Assuming you can find it and then apply that approach.

Anything in the yeast handling side of things that may be harbouring microbes?

By the Brewtools kit I was meaning the brew system. I'd only seen videos of the 60L system, I imagine a 150L system is even more complex.

 

[Mark Farrall]

And probably not worth the effort, but a pre-packaging, post-fermentation pasteurisation of the beer could tell you if the issue is occurring after fermentation. It'll probably kill the flavour of the beer, but it would rule out the packaging side of things. Assuming you can find some way to pasteurise that doesn't involve the packaging process, which I guess will be a challenge.

Edit: I suppose you could always take 100 mL samples at the end of the mash, the boil and prior to packaging and then store them warm for a week or two then sample. It might give you more info on where to focus.

 

[WesBrew]

Is malt being milled in the same area as the brewing & fermentation

 

[Asimi]

Is malt being milled in the same area as the brewing & fermentation

Yes, the same area

 

[WesBrew]

Malt and the dust has bacteria on it. It can get on everything. Best to do it outside. Since it’s also acid resistant, good idea to use some iodine based sanitizer, at least until it’s under control

 

[Dirty Dingo Brewing CO.]

...I would soak everything you have in iodofor for a few hours....​

Do you have a commercial name for that? I will try to find the analogs.

I'm using SS brew tech unitanks.

I work commercially and that is what we use as well

 

[Dirty Dingo Brewing CO.]

StarSan is an acid solution. Acid solutions have been proven to kill yeast.

We use acid commercially and homebrewing and neither has shown that the yeast is affected. I think that it depends on how well you dilute and how long before there is acid to yeast contact.

We use an ever stronger acid at commercial level, but we're religious about how much we dilute.

 

[Mark Farrall]

We use acid commercially and homebrewing and neither has shown that the yeast is affected. I think that it depends on how well you dilute and how long before there is acid to yeast contact.

We use an ever stronger acid at commercial level, but we're religious about how much we dilute.

Yep, it all depends on the dilution and how long you leave the yeast in the solution

 

[Daniel Parshley]

Most acetobacter love oxygen, so the increase in flavour with oxygen and the taste may point to that. I do love a few beers with a healthy dose of flavour from acetobacter, especially from Brouwerij Verhaeghe to the south of you. Though I do understand that I'm in a minority there. Not sure what's involved in killing it, though I've seen a lot of people very worried about it. Not sure if that's the taste or the difficulty of killing it.

Your silicon tubing can be pasteurised in hot water (or even boiled depending on the tubing), leaving the fermenter. Is it a Brewtools fermenter? If it is, I suppose you could use the brew system to generate boiling water to pasteurise/disinfect everything (if you haven't tried that already). If it's plastic have you checked for scratches inside the fermenter?

Probably the wrong time to ask, but how have you found the Brewtools kit? It looks very flexible. Maybe too flexible for my simple mind.

I had to boil all my tubing in PBW to remove a biofilm, and I was using Star San before and after brewing, and soaking in soapy water. After running some very dark English Brown through the tubing, I could see the film that was forming.

 

[Nosybear]

Why would you rinse your sanitizer, won't that increase the risk of recontaminating? Sanitizer should be the last thing a surface touches before wort/beer is added

Tap water is generally very near sterile, I wouldn't worry much about rinsing with it.

 

[Sunfire96]

Tap water is generally very near sterile, I wouldn't worry much about rinsing with it.

The water should be near sterile to be drinkable, but I've seen some nasty faucets and plumbing that I would not trust near a wort

 

[Nosybear]

The water should be near sterile to be drinkable, but I've seen some nasty faucets and plumbing that I would not trust near a wort

As have I. I don't rinse my equipment there, though.