Simple syrup should be stored in the refrigerator in a clean, airtight container. Here are the practical guidelines and typical shelf lives:

• 1:1 simple syrup (equal parts sugar and water): refrigerate and use within about 1 month. Some sources extend this to roughly 4 weeks; always check for off smells or mold before using.

• Rich simple syrup (2:1 sugar to water): refrigerate and it tends to last longer than 1:1, often several weeks to a couple of months depending on cleanliness and storage conditions.

• Sterile handling helps extend life: sterilize the storage container (e.g., by boiling and drying) before transferring syrup.

• Freezing is an option for longer storage: ice-cube trays or freezer-safe containers can keep syrup usable for months, though the texture may change slightly when thawed. Ensure the container is tightly sealed to prevent odors from other foods.

Quick tips:

• Use glass containers when possible; plastics can absorb odors over time.

• If you infuse flavors (herbs, fruits), expect a shorter shelf life—often about 1–2 weeks in the fridge.

• Always smell and inspect for mold or fermentation before using any stored syrup. If anything looks or smells off, discard.

If you’d like, I can tailor storage recommendations to your preferred syrup type (1:1 vs 2:1) and whether you plan to refrigerate or freeze.