Springwine was a Bajoran beverage made from fermented kava juice. It was made by the Bajorans for centuries, and was mentioned by Horran in his Seventh Prophecy. (DS9: "Ferengi Love Songs")
Springwine was sold at Quark's on Deep Space 9, and Kira Nerys had a penchant for it.
In 2372, First Minister Shakaar Edon plied Kira with springwine to get her to agree to attend a conference on Korma. During her trip there aboard the Groumall, Gul Dukat shared his last bottle of springwine with her over dinner, noting that it was one of the things he missed most about Bajor. (DS9: "Return to Grace")
In 2375, Quark offered Sarina a bottle of springwine on the house to get her to stop winning at dabo. (DS9: "Chrysalis")
Later that year, Odo ordered a glass of springwine for Kira after she attended services with Ranjen Telna. (DS9: "Covenant")
Benjamin Sisko intended to grow kava on the land he bought in Kendra Province, so that he could make his own springwine. (DS9: "Penumbra")
Kai Winn Adami intended to give a rare vintage of springwine from before the Occupation of Bajor to the Emissary of the Prophets as a wedding gift. However, she instead opened it in the company of Dukat, who was disguised as Anjohl Tennan, as she thought a Bajoran would appreciate it better. (DS9: "'Til Death Do Us Part")
The two enjoyed many glasses of springwine as Dukat worked to gain Winn's trust. (DS9: "Strange Bedfellows")
In scripts, the two-word spelling "spring wine" was used interchangeably with the one-word "springwine".