The drink, Papa Salt, is filtered through oyster shells, which she hoped would evoke the sandy dunes of Australia where she grew up. It means people with a shellfish allergy are advised not to drink it, because though the distilling process of gin removes most shellfish proteins, some can still remain when it is made with oysters. This is particularly of concern for those with severe allergies. Reactions to shellfish include anaphylaxis, which can be fatal.