I have made several batches of meads, using different yeasts, with the same recipe. I then picked the yeast that made the best mead (IMO) and made some fruit meads. I followed the same recipe, but added a jar of fresh fruit preserve to each batch (one raspberry, one blackberry). These are one-gallon batches.

The carboys ended up pretty full, and I couldn't add the whole yeast mixture. This worried me, as I wasn't sure if I would get enough fermentation.

However, my carboys keep popping the lids on the airlocks, and fermentation has been frighteningly fast. I have poured out a small amount of each batch to make some more airspace in the bottles, and it just filled up with foam again. I have fruity foam erupting out through the airlocks, more so in one batch than the other, and I keep removing them to clean and replace. It's only 3 days into what usually is a 2-week fermentation process, and they have finally slowed down (to a stop, I think, which doesn't seem right), and I'm not sure if something went horribly wrong, or if this is normal for a fruit mead.

And finally, I have mold on the top of the airlock of one of the batches now. (Horrible green-black stuff) where it is exposed to air. This doesn't seem to have penetrated the carboy though.

Is this batch savable? Is this normal for fruity meads? Have I done something wrong, and if so, can I fix it at this point? Has fermentation stalled, or actually finished? And will the speed of that fermentation ruin my mead?

  • The batch should be ok as long as your airlock did it's job. I know this isn't always easy but I would recommend pitching at a lower temperature like 62-64. It would be best if you could hold this temperature for a few days.
    – mreff555
    Commented Jun 27, 2017 at 19:14

2 Answers 2


It sounds like the extra sugar content from the fruit led to a faster fermentation. Small changes in OG can have large effects on the fermentation, particularly if the temperature isn't controlled -- the faster fermentation leads to higher temperatures, leading to even faster fermentation, etc.

Additionally, it's possible that the pectin from the fruit made the foam more stable, leading to the blow-off. In a carboy this, too can be a runaway process: once it's full enough that the foam extends towards the neck, the lower surface area means that it lasts longer, and builds up more. This is why I don't like doing primary fermentation in a carboy.

I wouldn't be too worried about the mold. You can replace the airlock if you want, but make sure to carefully wipe the inside and outside of the neck with alcohol before placing the new bung -- you don't want to inadvertently force mold down into the carboy. If the mold is only on the tip, probably worth keeping the current airlock until you rack.

It seems likely that this mead will have a harsher taste from the high-temperature fermentation, but only time will tell. I wouldn't write it off yet, though.


An option for the future is to ferment the primary in one big carboy or brew bucket (since it's all the same recipe), then add the preserves in the secondary.

Be especially patient with the blackberry mead. The taste of blackberry mead tends to start out at 'rocket fuel' before progressing to 'jet fuel' after at least a year. Getting it to the point where it actually tastes good can be a multi-year process.

Just how big were these jars you added? A massive addition of sugars like that could leave you with some very high ABV beverages that are sweet enough to mask how strong they are until you try to stand up. Or it could strain your yeast, resulting in off flavors.

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