I’m making a batch of ginger beer from a bug. 5l water, 400g white sugar. Within just over a day, the fermentation started foaming heavily. The foam has a consistency and taste of egg whites beaten for a merengue. The rest of the liquid is turning thick and viscous.

What’s happening?

2 Answers 2


Sounds like an undesirable bacteria / yeast combo. Try again with a new or known good ginger bug.


This is an infection from pediococci. They produce long carbohydrate chains that tangle together, which results in this viscous consistency. It's not harmful, it just feels gross. Reportedly, after a few weeks/months, a fermented product will return to normal consistency as the carbs making up the goop get broken down but I've never personally tested this claim. Whenever I get a pediococcus infection, I toss away whatever product happens to be infected and start a new batch.

  • Thanks! The viscosity did decrease a few days later - but somehow this batch ended up with very low carbonation. All perfectly drinkable, still.
    – Marko
    Sep 19, 2023 at 16:49

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