Mould spots in fermenter tap - is my brew stuffed?

[ferretlegs]

Hi Everyone, hoping I can get some opinions on whether my most recent lager is doomed.

I have a temp controlled fridge for fermenter and sometimes I get small spots of black mold on outside of fv by the end of the fermentation. This has never been an issue for me as obviously everything is sealed with blowoff tube into a water container etc.

After racking my most recent lager, when I went to clean the fv tap, I noticed 2 small spots of green mold on the inside of the fv tap. They would have been there the whole time that I racked my 3 kegs and all of the beer would have passed over them. I usually glad wrap the tap with a rubber band but forgot to this time and obviously mold has got inside the tap outlet, probably residual wort splash from taking OG sample.

Now I do hold out some hope because the FV was first crashed chilled to 1c for a few days, and all of my kegs have the headspace flushed with CO2 and are immediately put into temp controlled deep freezer at 3c when racked for lagering. So at no point will this racked beer get over 3c until the day it is tapped. I am hoping with lack of oxygen and continuous cold temp that the mold will not be able to get a foothold. Has anyone ever had this happen before, and if so, was the beer OK? Trying to find out if any mold is automatically game over or whether there is still a chance.

Any stories or insight on my chances would be greatly appreciated!

 

[axematt]

If it's kegged and ready to go,I'd say suck and see! You'll know if it's knackered. When I take my samples for gravity readings and tastings, I have a spray bottle filled with starsan in the fermenting fridge that I spray in the inside of the tap immediately after I have taken the sample I squirt it till its dribbling out and let dry out. Are you wrapping up your tap with glad wrap after you have taken samples? If so, I'd say that that would create a nice warm moist place for mould/bacteria to cultivate inside the tap. I think it would be better to leave it unwrapped....But this is just my theory.

Cheers

 

[FarsideOfCrazy]

Like axematt mentioned i wouldn't wrap the tap after taking a sample. I use either starsan or ethanol sanitser then just leave it to dry out.

As far as your original question, it depends on what type of mould it was, so it's a wait and see.

 

[ferretlegs]

Thanks for the replies! I will definitely not be tipping the beer after all the effort. I usually do spray with some starsan after taking sample but just forgot this time for some reason. Fair enough about not wrapping the tap. I was just hoping someone else has had the same issue and could let me know that they got away with it to give me some hope haha.

 

[DrJez]

If they're the clear/white plastic types, I pull them apart (inside comes out) and boil every brew before installing to fv. It's habit now after ruining a few brews due to gunk inside them years ago

 

[Brewman_]

The best way to evaluate beer is by taste and smell. That will tell you if its OK.

Some good comments above.
Always pull the tap apart and clean it. Doesn't necessarily need a boil, but a sodium percarbonate soak would do the trick. Then apply some food grade grease and reassemble.

What's the cause?
This is a topic I regularly discuss with brewers. They clean and then store the plastics away wet. Sure you can try to clean it and try to sanitise it, but I believe that a plastic piece that has been infected should be discarded. I don't trust them after that. Stainless and glass can certainly be cleaned and sanitised for future use.

The key point is that most bacteria and mould need water and oxygen to grow.
Clean plastics and let them dry right out before storing. With the tap, if it is still assembled it will hold moisture for some time and that may be what has happened here.

Anyway, I hope the beer is OK.

Sorry, will make one further point. So if the beer is OK, and I hope it is. That doesn't mean green spots and mould are ok in making good beer.

 

[peteru]

If you have inoculated your beer with something that can grow, it will eventually spoil the beer. It may be OK for a week or six while the contamination is subtle. If you find that the beer tastes and smells OK now, drink it quickly, before it shows signs of spoilage.

 

[ferretlegs]

Thanks for the extra replies. Yes I've always been worried about the plastic taps, I do soak them overnight in PBW and then spray with starsan before every re-use, but I have never pulled them apart before. Didn't even know you could.

The two mold spots were only a couple of mm each and they were very flat spots, not large growths, so I'm hoping that even drawing the sample for FG might have washed off the worst of it. There is no doubt the contents of all 3 kegs passed over them but I'm hoping that ongoing cold storage and C02 headspace might be an inhospitable environment, and therefore keep them preserved long enough to drink before anything bad happens.

Fingers crossed!!!!

 

[mongey]

Many of us brew out in our dusty garages or sheds. I have no doubt there have been many instances of gunk in the fermenter tap that went by un noticed and the beer has been fine.

 

[brewgasm]

These things are great for flushing out taps, I use them on my fermentors and keg fridge

 

[keine_ahnung]

Hey ferretlegs,

as already mentioned here, I'd def recommend always desinfekting your tap before and after taking sample and critically before racking (or letting anything flow through your tap that you want to keep as product).

Regarding whether it's automatically "game-over" or not, I wouldn't be tossing it just yet.

As you've already touched on, oxygen and temp are critical factors regarding the growth of all microorganisms. Add to that the influence of pH, alkohol, absence of sugar and some of the wonderful characteristics of hops, and you can happily ignore blanket-statements like "if it grew outside your keg, it'll grow inside your keg".

As part of my Braumeister degree, I have to study microbiology in the brewery. Quite in depth.
I can happily tell you, that your beer is NOT NECESSARILY stuffed.

There's not doubt about it -> no mold is better than mold.
I'm not agruing that at all.
But the outside of your tap is a completely different environment to in a keg.
i.e. aerobic vs aerobic (well....pretty damn close)
sugar presence vs sugar-free
no alcohol vs alcohol
20-10°C vs 3°C

Another fact is, you're probably not lagering your beer for 4 weeks, then bottling and putting on the market with a best-before-date of 6 to 18 months, where the bottles will go between 0 and 30°C who knows how many times.

There is a good to very good chance, that by the time you've finished your 3 kegs, nothing noticeable happens. Or maybe there will a small amount of further growth of whatever it is, to a point where maaaaybe you'll be able to taste something.

Then again, depending on what it is...you might end up with a sourbeer haha

Hard to say without knowing exactly what it is.

Either way, don't throw it out yet.
Think of it more as a lesson to be a bit more paranoid with your brewing hygiene