Tagged: tea scum

1. 01 The cup The cup · 18 Mar 2026 Hard Water Leaves No Scum on Rooibos, but It Does Age the Aspalathin The standing advice is to brew with filtered water because minerals in hard water dull tea. A 2023 study that tested rooibos directly against black and green tea found the usual reason for that advice does not apply to the red bush at all, though a different, real effect on rooibos's own chemistry does.