If you buy flavoured sparkling water or those flavour crystal packets, this alternative is cheaper and probably healthier.
“Shrubs” are fruit and/or herb and spice sugar syrups with a vinegar base. A simple 1:1:1 ratio of the fruit, sugar and vinegar is used. In the ‘cold method’ the cleaned and diced fruit is macerated with sugar, strained and then the syrup is mixed with the vinegar. In the ‘hot method’, vinegar is brought just to or under the boiling point, before it’s poured over the fruit and allowed to macerate overnight or up to several days. Then, the fruit is strained and the liquid is mixed with sugar. In both cases, the resulting liquid is stored in sterilized bottles under refrigeration.
I used an alternative to the cold method which I found posted here.
1 cup blueberries (any berry may be used though cherries, peaches, plums and pears are good too)
3/4 – 1 cup white sugar (you may choose to use the lower quantity of sugar)
1 cup unfiltered apple cider vinegar**
1 2-inch piece of fresh ginger, grated
In a large jar, combine blueberries and sugar and macerate with a muddler or the handle of a wooden spoon. Pour the vinegar over fruit and grate the ginger on top. Stir, cover with a lid and place into the fridge for 2-3 days until all sugar is dissolved.
Sieve the liquid through a fine mesh sieve, cheesecloth or coffee filter. (Don’t discard the spent fruit. It can be served over drained yogurt or added to smoothies or muffins.)
Place the sieved liquid into a fresh, sterilized jar and return to the fridge.
To serve, mix 1 tablespoon of the shrub syrup into a glass of still or sparkling water. Taste and add more syrup, if desired. Shrub syrups may also be used as cocktail mixers, in salad dressings, and more.
** According to on line sources (uncredited): Any vinegar may be used, as long as it is labeled as having at least 5 % acidity. Distilled white vinegar has a clear, sharp flavour but may be too acrid for most people’s tastes; apple cider vinegar tends to be milder with a fruity flavour; and wine/champagne vinegars, while more expensive, often provide a superior smooth flavor. Balsamic vinegar is delicious with cherries and strawberries.