I just brewed a raspberry wheat w/ ~2.5 lbs of frozen (organic) raspberries added to the secondary. I waited about 23 days after adding the berries to bottle, and when I went down to the basement to get ready for bottling day, I found this:

Bright white stuff on the color-drained raspberries

Bright white stuff growing on the tops of a few of the raspberries. I had checked it maybe 24-48 hours prior, and there wasn't any that I noticed.

Sniff test came back fine, so I was just super careful when racking not to disturb any of it (since none of it was in the beer). Taste test from the bottling bucket was also nothing surprising (pretty good, actually), and the SG was 1.011 (including priming sugar, 5.5oz of cane in 2c of water).

So what is this stuff? Should I be worried about my bottles?

Edit: Day eight of bottle-conditioning at ~72˚F, and I just vented + dumped nine bottles that looked roughly like this:

moldy bubbles?

It may be equally difficult to see, but I expect this must be "pellicle" forming. Some bottles had white-covered bubbles, and others had some hazy stuff climbing up the neck from the beer line. All were pretty fizz-tastic when I popped the caps (just a little to let the pressure out at first), and one smelled particularly rubbery.

The other ~36 bottles looked good. Notably, I think it was the last few bottles out of the bottling bucket that were the worst; I had one half-bottle (the last few ounces out) that I capped out of curiosity; he fizzed worst than the rest. There were "floaties" in a few as well.

  • Dear God! Don't make eye contact! It looks like it is infected, but I'd guess a taste test would answer any concerns. EDIT: Actually, just saw that you tasted it. Might not be bad then.
    – Scott
    Jul 11, 2013 at 15:15
  • This is only my 4th batch, so I don't know what to expect an infection to taste like. I can only assume that natural selection will have made it fairly noticeable, if it's a problem. And I've heard the SG is generally bone-dry for many infections? Mine was pretty much on-target with expectations.
    – Ben Mosher
    Jul 11, 2013 at 15:40
  • I'm in the same boat as you, only I've been brewing for years without ever brewing an infected batch, so I don't know first-hand what it smells/tastes like. From everything I've heard, the smell and/or the taste is completely distinguishable (vinegar, musty, moldy, rotten, etc...). The reason for the lower FG is because the bacteria strains will actually enable further fermentation of sugars the yeast would otherwise be unable to convert. I assume it's too late now, but a few other photos would help. Maybe even one facing down the hole in the top of the carboy.
    – Scott
    Jul 11, 2013 at 16:42
  • 1
    Man, you tempt me to get a couple 1-gallon secondaries and try for a test... there are a lot of potential confounding variables, though. I mostly just want to support organic principles and minimize my chemical cocktail uptake.
    – Ben Mosher
    Jul 12, 2013 at 18:56
  • 1
    Wow... better get Uncle Randy to help you with the next batch!
    – Jeff Roe
    Apr 27, 2017 at 5:20

2 Answers 2


At first when I looked at it, I thought the bright white stuff you mentioned was actually glare from the lights with the distortion of the carboy, and that you were talking about the raspberries, which have since lost most of their color and look more like brains, if anything.

Now that I know what you're talking about, that is definitely mold/bacteria, with a very high chance that it has gotten into the beer. How well did you rinse the raspberries before putting them in? Regardless, yes, I would be concerned, but, there is always hope. Here's what I would do, given the supplies I have on hand. I would take a large beer cooler (or two) or anything that can contain liquid and withstand a bottle exploding in it, and store the bottles (upright) in the beer cooler for conditioning. In case they turn into bombs, the cooler will act as a container to keep all the glass and beer from blasting everywhere.

By the time you want to drink one, carefully take one out, and examine it for a pellicle at the beer line. Use a flashlight to look at it to see if there appears to be a sort of film resting on the top of the beer (a ring around the beer line is a good hint in this case, but is not always a clear indication). If there is a pellicle, the batch should be considered entirely bad. At that point, store the beer as cold as you can without freezing it to slow down any further fermentation. Try and crack one open in a wide open area (back porch, bath tub, somewhere with head space and can get wet. For protective measures, wear safety glasses and gloves with minimal skin exposure in case it's worst case scenario. If it gushes out, geyser or volcano style, and you're sure you added the correct amount of priming sugar, that's a clear indication as well that it is contaminated("infected"). You can try tasting it, but I can almost guarantee you won't want to once you get a smell of it.

A few side notes worth mentioning. There is a chance that, like you said, the bacteria may not have come in contact with the beer. The bacteria looks minimal (at this point), so that may explain the lack of a noticeable taste or smell, or the bacteria could have gotten in just enough to screw up the batch. There's no way to tell at this point. I will caution though, if one goes off in the cooler, pitch the rest. You don't want to risk the damage, especially if you have kids, pets, eyes, anything that could suffer from glass shrapnel should you happen to have one go off when tipping it over in the fridge by accident.

Also, clean everything super-thoroughly. Your carboy, racking cane, even take apart the spigot to your bottle bucket and bleach/clean the snot out of everything. Bacteria is known to linger in plastic, so make sure you do everything possible to prevent it from coming back in your next batch.

Fruit in secondary is a great thing, but it also carries risks since it isn't boiled/sanitized. This is that negative outcome of that risk. The biggest thing I want to stress though is to not let this get you down. Seriously, don't let this be the end. Contamination is not common, even in fruit beers it isn't as common as some people may lead you to believe. You just have to make sure you have good sanitation practices. Next time, try pureeing and pasteurizing the fruit before adding it. You'll get more flavor from the puree, and it'll be free of any bugs.

Sorry your 4th batch turned out like that. Hopefully the other three were good enough to keep you in the game, I can imagine that seeing an entire batch go bad has to be demoralizing, but there's a lot of good beer to come down the road.

  • No rinsing; there was a lot of syrup that I wanted to keep for flavor. They were previously frozen, but IIRC they were in the fridge to thaw out (in the bags) for about 3 days.
    – Ben Mosher
    Jul 12, 2013 at 18:49
  • @BenMosher would pureeing and/or pasteurizing be consistent with the organic principles? Jul 12, 2013 at 23:49
  • @MatthewMoisen - I think so. I read about the process for pasteurizing, but in most of the first-hand accounts of brewing with fruit I could find online, folks said they didn't bother with either. Just freezing to break up the cells' internals.
    – Ben Mosher
    Jul 16, 2013 at 0:49
  • Note: day 5, no pellicle or bombs so far. Going to wait until day 7 to cool down and pop one open.
    – Ben Mosher
    Jul 16, 2013 at 0:51
  • Good to hear. It's hard to tell when it may become noticeable, if it is infected at all. Day 7 would be a good start, as well as 14, and 21. If by then, there's nothing, I'd be confident that you're free and clear to enjoy it as is.
    – Scott
    Jul 16, 2013 at 5:00

It's definitely contamination, but I doubt it's made contact with the beer, since most contaminats at this stage feed on oxygen and perish in alcohol, plus it's just a little on top of the fruit. Since the beer smells and tastes fine now then rack from beneath, chill and force carbonate (if you have kegs), or prime as usual if you bottle-carbonate, then chill to prevent any further growth.

As a wheat beer you should be drinking this young - within a few weeks at most.

Next time you can warm the fruit to 170°F/76°C which will kill the majority of contaminants without driving off much aroma.

I think this one looks worse than it is.

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