Union Square Café's Mad Scientist

In the wine cellar of restaurateur Danny Meyer's perennially popular Union Square Café, there are a few large mason jars of neon-yellow liquid. The contents are not radioactive: The jars contain housemade limoncello , created from a family recipe provided by the restaurant's youthful, experiment-loving wine director, Stephen Mancini.

The lemon-based Italian liqueur, mixed with grappa and citrus juices, is used to make the Forza Totti — one offering from the new cocktail program Mr. Mancini has been developing since last fall. The 27-year-old puts much stock in family recipes. He and his father cure their own prosciutto every year, and his first exposure to wine was the garage brew whipped up by his grandfather. Mr. Mancini's uncle has now assumed the family winemaking duties, aging the alcohol in glass, which lends it a bit of carbonation. "It's not as much about making an amazing product as it is about tradition," Mr. Mancini said.

Noting that his staff could similarly benefit from firsthand exposure to winemaking, he said he's discussed with Union Square's general manager the possibility of making wine at the restaurant — not for patron consumption, but for educational purposes. The idea came to him last fall when he voluntarily assisted Californians Bob Foley and Abe Schoener with their harvests. "Who knows? We could make the worst wine ever," he said. "But being able to share that experience I had with Bob Foley — drinking juice that was not fully fermented out of his 10-ton steel fermenters, seeing how that wine has evolved — it was brilliant."

Mr. Mancini hails from Italian immigrant families on both sides: His father was born outside of Rome, and his mother's family came from Calabria. After graduating from Villanova University, he worked his way up to captain from busboy at Mr. Meyer's Gramercy Tavern, and learned about wine under the tutelage of former Gramercy Tavern sommeliers Paul Greco and Karen King. Union Square Café is his first gig as a full-out wine director.

He tends to look at Union Square's wine list as something like a many-layered archeological dig. "I'd say that I've definitely been able to put my fingerprint on the list," he said. "That being said, this list is different than a lot of lists in New York City. It still has purchases that Danny Meyer put on the list originally. Every wine director since Danny has made a contribution."

One of Mr. Mancini's major innovations is a full page of grappas. They hail from a range of Italian regions and include a 1984 Bric Del Gaian from the Piedmont ($50 a glass). "I think sometimes people have a preconceived notion of what grappa is," he said. "We have such great Armagnacs and Cognacs here. Since our list is very much an Italian list and our restaurant very much has an Italian soul, if we're going to support the after-dinner-drink lifestyle, it's only right we have a grappa page."

Another new aspect is the aforementioned cocktail menu. Each cocktail contains an Italian ingredient made in a different area of the country, and Mr. Mancini has arranged the menu in the manner of a wine list, ordering the drinks region by region, running from the top of the Italian boot (a Venetian Spritz made with proseccoand Aperol) to the bottom (a Sicilian Wallbanger, made with imported Sicilian blood orange juice, vodka, and Galliano liqueur).

"I didn't want to just make drinks and say, 'These are our cocktails' — a drunken cranberry spritzer or whatever," he said. "So I made it all Italian. We find our inspiration for these drinks from an ingredient from a region."

Future cocktails may benefit from Mr. Mancini's mad-scientist proclivities. He's experimenting with homemade versions of the Italian herbal liqueur known as amaros , as well as a juniper-infused gin. At this rate of invention, the Mancini grandchildren will have considerably more family recipes to choose from.

Union Square Café (21 E. 16th St., between Fifth Avenue and Union Square West, 212-243-4020).