I'm looking into adding a pink color into a fruit flavored gin.
Other than carmine, are there any other tips / ideas to achieve this (easily) to ensure consistent coloring + stability?
Keep in mind, the reason why carmine has been one of the most popular colorings for the past 500 years, it has the best stability of any of the natural red coloring agents. The most stable when it comes to light, heat, and oxygen. Safe in food. Anything else is a far, far away second place. Color shift to brown is a real problem, and unless you can move product quickly, and have it consumed quickly (don't we all wish), it's going to become a product perception problem.
Stability is going to come down to reducing oxygen exposure. This might mean changing your workflow to ensure you aren't adding oxygen at any stage in the process, it might also mean needing to add stabilizers.
You are going to need to get into some hardcore food science:
Tgf, Did you ever find a solution to it?
Hapido, unfortunately, no!