This PGI also denotes that Plymouth is a style of Gin, as well as a brand. It is thought that the PGI was acquired (back in the 1880s) to protect the reputation of the brand which was supplying over 1,000 barrels of Gin to the British Royal Navy at the time.
Plymouth Gin is traditional in its botanical makeup (juniper, cardamom, coriander, angelica root, citrus peels and orris root), although less so in flavor. It’s a particularly smooth Gin due to the higher number of root botanicals, giving an earthier feel than a London Dry Gin. It works well in Martinis and Gin and Tonics alike.