Check out this mold...

[slcmorro]

So, I have this little bit of mold on the top of my Pils I brewed recently.

It's been in the fermenter for about 3 weeks now, and the grav is slowly but surely dropping. I used Wyeast 2001 however it had a massive lag time (I made a 2L double stepped starter but obviously 5L would have been better) and took about 4 days to show visual signs of fermentation.

It originally tasted popcorny, and has now mellowed out quite a bit but still has a slighty 'off' taste to it - hard to put to it what it precisely is.

I'm happy for it to do it's thing til it's done, however can anyone shed any light on what it might be?
I thought it might be due to oxygen exposure perhaps (sealed ferm fridge, but only gladwrap on the top)

 

[Kev R]

Keep the lid on. I fear you may be starting a rival life form

 

[Judanero]

Looks like trichoderma, is it near terminal gravity?

 

[Rocker1986]

That's a bloody long lag time. I've been using the same yeast in my pilsners with just a single 4 litre starter, stealing 800mL for future use then repeating the process each batch. Pitching about 10C, they've been taking off in around 30-36 hours, current one was showing signs in about 24 hours and fermented out in about 8 or 9 days. I did raise the temp on day 5 though.

How long has that thing been in there? I had one in a lager a couple of years back due to an infected yeast starter (which I only realised after the fact). It appeared only a few hours after pitching the yeast, so I decided to sanitise my mash paddle and fish the shit out. The beer turned out perfectly fine in the end.

 

[pist]

Put that lid back on man! Exposing to air will accelerate growth of whatever that is. The "popcorny taste" could maybe be diacetyl especially if its like buttered popcorn. Whatever that is, can't be good though. Keg when done if it still tastes ok when done and drink fast

 

[TheWiggman]

I did a few pilsners with WLP800 which I understand is the equivalent to 2001. I did a stepped starter on one (1l - 3l) with 2 vials of 3 month old yeast. I've found that doing small steps like this had an adverse effect on the taste which, like you say, is hard to put your finger on. Assuming you have a 3l flask, I'd advise you to go straight to 3l using fresh yeast. This has absolutely made a difference to the final product in my experience. And all the other stuff like O2, yeast nutrient, warm starter etc.

The lag time and long ferment indicate poor yeast health and/or non-ideal wort conditions, which for a pilsner are critical things to address. A long lagering period should improve it.

Regarding the mould, I think O2 exposure would help it along but it would have to be in there to start with. If I were you I'd skim it off. Happy to be proven wrong but surface mould shouldn't have an impact on flavour, certainly not in that quantity.

 

[slcmorro]

Looks like trichoderma, is it near terminal gravity?

It is nearly there now, but this appeared very early on in the piece.

Lid only came off for the photo FYI. Thanks all for the time and advice

I'll let it do it's thing until FG is reached, and then it'll be lagered until at least November if not longer.

 

[gaijin]

Reading this got me curious as to what trichoderma was, so I tracked down the wikipedia page on it and I found this under medical uses of the fungus...

Cyclosporine A (CsA), a calcineurin inhibitor produced by the fungi Tolypocladium inflatum[12] and Cylindrocarpon lucidum, is an immunosuppressant prescribed in organ transplants to prevent rejection.

You might've created the first beer to prescribe to organ transplant patients! Awesome!

 

[welly2]

Keep fermenting it until it tastes really weird and then call it Belgian or "Farmhouse".

 

[spog]

Reading this got me curious as to what trichoderma was, so I tracked down the wikipedia page on it and I found this under medical uses of the fungus...

Cyclosporine A (CsA), a calcineurin inhibitor produced by the fungi Tolypocladium inflatum[12] and Cylindrocarpon lucidum, is an immunosuppressant prescribed in organ transplants to prevent rejection.

You might've created the first beer to prescribe to organ transplant patients! Awesome!

Do you mean it's gentle on your liver while you drink ?

 

[gaijin]

It helps your body be gentle on your transplanted liver which you got because you screwed the last one up drinking...maybe...

 

[Ducatiboy stu]

Mould is good in Cheese


Not so good in beer


All I can say is slcmorro........You need to get a few more beers under your belt

 

[slcmorro]

Mould is good in Cheese


Not so good in beer


All I can say is slcmorro........You need to get a few more beers under your belt

We all do. Can never have too many now can we?

This is the first time I've ever had even a hint of infection or the like. I've either been very lucky with the 77 other AG batches I've done (according to my BrewMate logs), or I just had too long a lag time by using too little yeast in this batch.