How long can I keep shrub syrup in the refrigerator
While, in general, vinegar retards the growth of certain bacteria (botulism), some allow the growth of others that are harmful. You should sterilize the glass containers by first washing them in hot water and soap, and then boiling for about 10 minutes and scalding the caps in boiling water. Filled and tightly sealed, your shrub should last about 6 months in the refrigerator. Opened and used occasionally, they should last 6-8 weeks, not unlike similar condiments that are kept refrigerated. Keep in mind that, should you include fruit in your original batch, it will age and, eventually, become a fruit vinegar.