Yeast strands are normal: they appear as brown, wispy threads hanging from the SCOBY or floating in the liquid. Mould is not normal: it appears on the surface as fuzzy spots that are white, green, black, or pink. Mould in kombucha means the batch must be discarded — it cannot be removed. Prevention: maintain a pH below 3.5, keep your vessel clean, and ensure your SCOBY is properly covered with starter liquid.
For a deeper dive into related topics, explore our full Tea Learning Hub with over 500 expert articles.