

Interesting foam on apple cinnamon ginger soda
Started yesterday. Boiled ~30g roughly chopped ginger and a stick of cinnamon in 1l apple juice from concentrate for a few minutes, then took the ginger out and left it to cool with the cinnamon in. Once cooled, added to a bottle and topped up with ginger bug (estimate 1/3 cup). Fermenting well, but I noticed a massive bubble on the top separating some of the foam from the rest. It kinda deflated when I opened the bottle but rose back up when I closed it. It went away when I tipped the bottle upside down. Is it something to worry about, or just odd foam? I'll check on it later anyway.