The contents: a low concentration saline solution that’s 10:1 distilled water to kosher salt by weight.
Low concentration salt actually helps to control or reduce bitter flavors, but amplifies sweet and sour,
Scientists believe that the sodium ions block the palate’s ability to sense the bitterness, making sweetness or sourness more perceptible.
Ultimately, the effect salt has on a drink really depends on the other ingredients it’s joining: citrus becomes brighter, drinks with egg white become more aromatic and drinks topped with sparkling wine get a bit sharper.
Saline in low concentration helps to brighten up sour and sweet flavors, so citrus instantly gets a big lift,
The salt will give structure to the whites themselves by stabilizing the protein chains.
Salt particles will also help augment the sensation of the bubbles in a drink by causing CO2 gas to be released more rapidly.
The reaction between salt and Champagne or sparkling wine has some textural influence on a cocktail, too, creating what Politi considers a more precise sharpness by playing up the dryness of the wine.
If you have carbonated water, you have that distinct flavor of CO2 and salt can counteract that flavor,
you get a more pure, heightened flavor from the cocktail itself.