If you pour your finished cordial into bottles that have been scalded and rinsed with vodka, it can easily last for several months or longer in the refrigerator. However, I prefer to freeze the finished cordial. A smart trick is to freeze it in ice cube trays or bags, so you can easily add a few cubes to a glass of water, sparkling water, or even Asti when the hot summer days arrive. Then you'll have refreshing cold drinks that taste delightful.