Homemade simple syrup usually stays good for about 2–4 weeks in the fridge for a standard 1:1 sugar-to-water mix, and up to around 1–3 months if it is a thicker “rich” 2:1 syrup and stored very cleanly in an airtight container.

Basic time frames

  • 1:1 simple syrup (equal parts sugar and water), kept refrigerated in a clean, sealed bottle, is typically best used within about 2–4 weeks.
  • Rich 2:1 simple syrup (twice as much sugar as water) can last several weeks to a few months in the fridge because the higher sugar content slows microbial growth.
  • Flavored or infused syrups (with fruit, herbs, or spices) generally have a shorter life, often around 1–4 weeks depending on the ingredients.

Signs it has gone bad

  • Cloudiness, visible mold, or strange “strings” or films in the liquid mean the syrup should be discarded.
  • Off smells (fermented, sour, or musty) or a noticeably odd taste are also clear reasons to throw it out and make a fresh batch.

Storage tips to make it last

  • Use a very clean, preferably sterilized glass bottle or jar with a tight lid to store the syrup in the refrigerator.
  • Label the container with the date and ratio (for example, “1:1 – made Dec 1”) and plan to make small batches so you finish it well within that 2–4 week window for regular simple syrup.

Information gathered from public forums or data available on the internet and portrayed here.