I’m sorry, that always stinks when a project doesn’t turn out so great 🙁 The leaves will turn dark and change texture, the picture shown here is right after I’ve made it, so they look fresh and bright there, but they don’t stay that way. Did you use fresh or dried mint, and was it packed tightly into the jar? It may be that you didn’t use enough mint. And did you shake the mixture every day or so? The liquid will be edible as long as there’s no visible mold or spoiled smell to it (which wouldn’t be likely). I have found that homemade mint isn’t as strong as the store bought kind anyway though.

Sarah, have you shared your extracts made with vegetable glycerol recipe online? I’d love to see them.