First, the curve of the glass, which at the top does curve back in, helps trap the aromas of the gin within the glass, yet still allows it to breath. This helps open up the flavours of the gin. Allowing the gin to breath is important, especially if you’re using an especially floral and nose heavy gin. Additionally, the bowl shape of the glass does allow for additional ice, plus your hand is not warming the liquid but instead is holding the stem, so the ice doesn’t melt as quickly.
As gin and tonics have come into the modern era of drinking, more and more variations have come out, many of which feature unique garnishes. It’s hard to truly appreciate some of these garnishes (or for the garnishes to even remain in place) when served in a rocks glass. The curved lip of the Copa glass helps contain the garnish, making it possible to garnish your gin and tonic with basically anything.
Your favourite G&T glass branded with the steampunk inspired Dullstroom Gin Monogram.