Possible Clues:

• A high-quality French brandy
• Oddly, cool gin is extremely acidic unlike this, more expensive drink
• Charlie may turn up for drink
• Do talk on radio? This could be fine
• Cold is able to disappear after knocking back alcohol
• About half of a sidecar
• Warming drink may go cold if sent back
• Copy essential knack making spirit
• Tipping over receptacle, leave cold drink
• French spirit