Club soda and sparkling mineral water both have bubbles of carbon dioxide gas suspended within their liquidy matrices, but it's their other additives that define them. Here are the key differences (and what you should use them for.)
- Soda Water: Soda water is plain water with added minerals and dissolved solids, usually sodium bicarbonate, sodium citrate, disodium phosphate, and -- less commonly -- plain ol' sodium chloride. The carbonation is added, rather than naturally occurring, and the taste can range from practically flavourless to slightly salty or bitter. Its lack of strong flavour makes it a good choice for adding some effervescence to cocktails or juice.
- Sparkling Mineral Water: Sparkling mineral water usually comes from a natural spring or well, and can be naturally carbonated, depending on the source. As its name would suggest, there are some minerals in there, though the type and amount of dissolved solids vary from brand to brand. Mineral water is usually best enjoyed on its own, as the flavour imparted by all the minerals (such as magnesium, potassium, and calcium) can be distracting in a cocktail.
Now that we've got that cleared up, I recommend celebrating with a bubbly beverage. Whether or not it's boozy and bubbly is up to you.