Herbal or fruit syrups (lavender, mint, strawberry) go bad in 1 to 2 weeks because the added plant matter introduces extra sugars and enzymes. That’s why professional cocktail bars make them fresh daily—or at least act like they do. If your berry syrup is older than your last haircut, just toss it.
Demerara or rich simple syrups (2:1 sugar ratio) last up to 6 months in the fridge because the higher sugar concentration acts like a tiny desert. That’s also why honey is basically immortal—but honey has its own crystal-crazy issues.
The Final Sip
Bottom line: One month is the safe zone for basic simple syrup. After that, you’re playing Russian roulette with your digestive system. The best test? If you have to ask, “Is this still good?” the answer is no. Throw it out. Make new syrup in 10 minutes. Your future self—and your Friday night cocktails—will thank you.
And if you do accidentally drink week-old moldy syrup? Don’t panic. You’ll probably just have a mildly philosophical bathroom break. But next time, label your bottle with a date. Because future you is a forgetful goblin who will absolutely ignore that fuzzy green blob.
