Since you spent the money so the charitable organization would not have to, and immediately transferred the purchase to the organization for use at the event, I would consider this to be a cash contribution.
Be certain to obtain a signed, detailed receipt for the wine (vintner, variety, year, number of bottles/cases, value) from the recipient organization and keep that receipt and your purchase receipt with your tax records for the year.
Further information about charitable contributions can be found here: IRS Pub. 526 Charitable
Contributions.
