Could also be to keep them white? I used to see teabags last century (and health food shop teabags nowadays) yellowing similarly but commercial Twinings tea bags these days remain white - could be a chemical impregnated into the paper but that seems likely to leach into the tea.
Could also be to keep them white? I used to see teabags last century (and health food shop teabags nowadays) yellowing similarly but commercial Twinings tea bags these days remain white - could be a chemical impregnated into the paper but that seems likely to leach into the tea.