A beverage preparation system is provided comprising a beverage preparation machine, a cartridge containing one or more beverage ingredients, and a coded insert. The beverage preparation machine comprises a brew head for receiving the cartridge. The cartridge comprises a primary code configured to provide operating instructions to the beverage preparation machine for delivering a beverage from the cartridge. The coded insert is separate from the cartridge and insertable along with the cartridge into the brew head. The coded insert comprises a secondary code configured to provide alternative operating instructions to the beverage preparation machine for delivering a modified beverage from the cartridge.