Identifying an infection, and how to salvage.

[GV00]

My other thread isn't getting a whole lot of traffic, probably because the latest issue is buried under my initial fears, and I suspect this is a time-sensitive matter that I've let go about as long as I can afford, so hopefully this one will do better. If it's bad form to split a thread like this, sorry.

Anyway, I started my first batch of mead about two weeks ago. Raspberry honey, with Wyeast 4184. I only learned that the smack packs are generally considered insufficient for larger batches (this is 5g), so it's likely that I underpitched. Fermentation seemed slow, dropping about 14 points in the first 5 days, and since then it's only really gone down another 1 or 2. Pressure changes resulted in the airlock water being sucked into the carboy at one point, which is I'm guessing how this happened. Something seems to be growing in there...and I think it's probably nothing good. A surface layer of tiny white dots on a film of haze started showing up, and now it's developing mats. Bubbles get caught in it before reaching the surface, and the top layer has since developed tendrils that hang an inch or two below the surface in a rather gunky-looking layer. What I thought was the yeast cake on the bottom is doing much the same thing -- spires of cottony murk that stand off the bottom.

Here's a couple pictures, including one backlit to give some idea where the concentrated patches are.

Any idea what it is? Assuming it hasn't started to taste unbelievably foul, is there any salvaging it? Boil the must? Try to pasteurize on a lower temp? Any chemical solutions that will kill everything, no holds barred, and later allow me to reinnoculate?

 

[pghfett]

I'd like to respond and offer up some advice GV but truth be told, I'm a beginner myself.

Have you opened it and at least smelled the must? I personally do not like the "black" cake in the one photo.

I have however seen "white" cakes and debris on the bottom of my Cyser and mead which is normal. I've never seen a black formation/cake however.

If you determined it's bad - get it out of your brewing equipment asap. infections are hard to get rid of.

sorry not much help

 

[GV00]

It's not so much that that's actually black, it's just backlit in that photo and it gives you an idea of its thickness. If it weren't for the strange dangling masses and specks of white/off color, complete lack of any airlock movement, and the lack of SG movement, I might be able to convince myself it was just some krausen. In fact, I'm going to do a taste test / hydrometer reading / pH test before I try to strain everything out just to make sure it isn't. I'm new enough that I'm well aware I could be grossly incorrect in thinking something is wrong, but I can't help but still feeling that's the case.

Last time I smelled it, it still smelled like honey. My nose isn't the best, though, so I don't completely trust it.

 

[sweetcell]

get more yeast in there ASAP. your single smack-pack was insufficient, by a lot.

you could either buy several more smack-packs - like 4 of them - or get 2 packs of dry yeast, rehydrate with Go-Ferm, then pitch. have you added any nutrients to your mead? honey is nutrient-deficient. if you haven't added anything, look into "staggered nutrient addition". you'll want a small amount of Fermaid and DAP, added over several days.

all of the above should get the yeast up to speed and take over the fermentation.

you could bomb the mead with some campden. that might stun whatever is currently in there. wait 24 hours, then add rehydrated yeast. no guarantees that the campden will affect whatever you've got in there (of anything, could be the 4184 for all i know). personally i'd go straight for adding more yeast, and skipping the campden.

 

[GV00]

If there's that much crud and gunk in there, I've got to wonder if yeast is going to be able to out-compete it. Plus there's the issue of the Turkey Day Weekend here in the states -- I'm not even sure I can get more yeast until Monday, as I don't really have much on hand aside from a few experimental starters made off of some of the 4184 I saved. I could try to make more, but I don't have much aside from nutrients, fermaid-K, and some honey around to actually feed the stuff, so I'm not sure that it'd work too well. Hence my thoughts on simply straining and boiling the must, campden-bombing it, and trying to pick up some more yeast on Monday or tossing both of my jerry-rigged starters in and hoping for the best.

Either way, I'm going to take a sample in about an hour, taste test it, get a SG & pH, and then set to work on it. Hopefully whatever's in there hasn't grown eyes to stare back at me yet.

So on the boil side, since it seems like the surest way to kill what ails it, other than driving off aromatics I might want (and thus producing what might be a mediocre mead at best), are there any downsides to outright boiling the must?

How about equipment cleanup after the fact? Good solid scrubbing, plus steeping everything that's touched it in bleach water for a while? The carboy's glass, but the bung, airlock, tubing and autosyphon, etc. are mostly plastic.

 

[GV00]

Just an update: I went to check on it earlier as planned and take a few readings -- and found the airlock ticking along. Pulled the T-shirt I had on it off, and lo and behold the "infection" had turned into something much like the krausen/yeast rafts I've seen on cider so far, although there's still a few bubbles trapped in white gunk on the raft, it looked pretty much as I'd have expected.

So maybe I just set a record: Two and a half weeks for fermentation to really start.

Taste test was...well, honey and water, although it was highly carbonated (just spinning my hydrometer was enough to raise an inch of fizzy foam in my sample tube) and had a bit of an electric bite -- I'm guessing that's probably just excessive carbonation, since it kinda had that zip to it.

Getting an accurate SG reading was tough, as the must was opaque enough to make reading below the meniscus damn near impossible. From what the top of the meniscus was, I'm going to guess it's about 2 points lower than it was 5 days ago. Seems odd to me, given the yeast activity, but maybe it just really, REALLY ramped up today for some reason.

pH was 3.2-3.3 or so, best guess from my strips.

I gave the carboy a swirl afterwards in a gentle attempt to get rid of some of the carbonation. It sounded rather angry as a result, but didn't foam up a ton. However, it did circulate some of the krausen around...at which point I noticed that I most certainly DO have an infection, if not the magnitude I expected. There's a spot of mold growing on one of the yeasty mounds on the surface. Right now it's only about half the size of a penny, but it's a dark blue/green color, with a white rim. The headspace for the activity up until now was way too much (I'd expected much more activity), so I'm pretty sure there was never enough CO2 to buffer it. Amusingly, that's changing now, but the infection's already there. I'm going to try to syphon out from under the top layer tomorrow and shift it from the 6.5g carboy to a 5g I've got handy, hopefully eliminating that headspace (though I may have to top up with some apple juice). I guess I'll just have to make a habit of degassing regularly and have a blowoff tube ready to shove in in case it goes nuts. Hopefully the mold won't have a chance to retake.

I know dosing it with campden tabs would stun the yeast, but would it knock out any remnants of the mold? Am I better off crushing some and going that route, or just siphoning out what I can and hoping the yeast provides a suitably hostile environment before the mold can re-colonize?

 

[sweetcell]

my suspicion is that the yeast spent all that time trying to reproduce and get their cell count up high enough to ferment all that sugar. with no nutrients in there, i doubt they reached the required population. i wouldn't be surprised if they crapped out early and you didn't attenuate fully. still can't hurt to get more yeast in there.

If there's that much crud and gunk in there, I've got to wonder if yeast is going to be able to out-compete it.

i'd put my money on the yeast. by pitching a pack or two , you're adding hundreds of billions of cells. they don't need to out-compete so much as just plain take over due to numbers. unfortunately they won't clean up any damage made by the infection, such as off-flavors. hopefully you didn't pick up any of those.

Hopefully whatever's in there hasn't grown eyes to stare back at me yet.

lol

So on the boil side, since it seems like the surest way to kill what ails it, other than driving off aromatics I might want (and thus producing what might be a mediocre mead at best), are there any downsides to outright boiling the must?

i'd try pasteurizing instead: raise the must's temp to something over 155*F for at least a minute and you're set (http://www.engineeringtoolbox.com/pasteurization-methods-temperatures-d_1642.html). better than a full-on boil - less damage to the must.

How about equipment cleanup after the fact? Good solid scrubbing, plus steeping everything that's touched it in bleach water for a while? The carboy's glass, but the bung, airlock, tubing and autosyphon, etc. are mostly plastic.

depending on your risk tolerance, you can try going with bleach on the plastics. i'd try heating (in water that is at least 160*F if not hotter) whatever i could. actually, no - i'm paranoid about cross-contamination and i'd dedicate those plastics to sour beers only (or just throw them out if you don't dabble in sours). but some folks use the same plastics for clean and sour, so YMMV.