A handful of Central Otago wineries are producing wines that are suitable for vegans and vegetarians to drink.
Wine is not something one normally thinks of as containing animal products but Rockburn Wines' winemaker Malcolm Rees-Francis said many wine-makers added a protein substance called a fining agent to their product to make the wine less tannic and more drinkable.
Agents included animal-derived products such as egg albumen, gelatin or isinglass (from fish bladder membranes).
''It is surprising how common it is,'' Mr Rees-Francis said.
He said the agents clarified the wines and removed the tannin but he did not add any agents to Rockburn's Wines.