Dani Corman sits back and relaxes in Bergara at a bar piled high with colourful, freshly turned out pintxos – the bite-sized Basque tapas that are the trademark of the city’s cuisine. “When it comes to San Sebastián it’s all about sourcing the finest ingredients and then working wonders with them,” he says, taking a bite out of a tortilla de anchoas, a warm and gooey Spanish omelette made with anchovies. It’s a Bergara speciality that has been on the menu for more than 20 years.

It is equally important, however, which wine you pair with the perfect pintxos and that’s where Dani steps in. His wine shop and distribution firm Essencia draws up wine lists for local and Michelin-starred restaurants in the city and also supplies them with wines.

“I’m on a mission to open customers’ minds and develop their palates beyond the riojas and riberas,” he explains. Budding sommeliers flock to the professional sommelier courses and wine tastings held at Essencia, which is located in the neighbourhood of Gros, a culinary enclave that Dani is keen to show us.

Dani starts the day off with a freshly squeezed grapefruit juice for breakfast in the bustling bar-cum-restaurant Andra Mari. Here, croissants and pains au chocolat are served in the morning and the restaurant’s attention is turned later in the day to savoury offerings, such as “lacquered” langoustines with baby vegetables.

After a look around the Solbes gourmet store, where shelves are packed with everything from Wilkin & Sons preserves to a paletilla of Jamon Iberico – we head off to visit some of Dani’s loyal local customers. First up is Kike Garcia, the formidable owner of El Lagar, another pintxos bar, where the punchy wine list is drawn up each month with Dani’s expert help.

Then we head off to sample the delights of the menu at restaurant Viento Sur. The owners, Eugenio Rafel Quijada and Carmen de Isla Torres, uprooted from Andalusia to Gros, where they are behind creative dishes such as scallops with beetroot foam, salmorejo soup – and wines such as Jacques Lassaigne champagne that are bought, naturally, from Dani’s wine shop.

“I look for small, lesser-known winemakers,” says Dani. “The wines have to be organic or biodynamic. And it’s important to know who is behind the wine. They must be passionate about what they do.”

This kind of passion is evident when we stop for lunch at the family-run Saltxipi, an establishment that is a favourite with locals and visiting VIPs alike. We are greeted by Gorka Ortega, who shares front-of-house duties with his father, while his mother and brother take care of the kitchen. We start with an appetiser of croquetas and then we’re presented with two whole spider crabs. Our appetites satisfied, we then head up the hillside overlooking Gros to the Mirador de Ulía, where chef Rubén Trincado recently picked up a Michelin star.

Awaiting Dani is a group of local culinary experts, including Juan Mari Humada, the man behind the Hidalgo 56 pintxo taberna, and Iñigo Galatas, prominent food critic and broadcaster. As we bid our goodbyes, Dani is stuck into a wine-tasting session organised by Iñigo for the region’s newspaper. Earlier in the day Dani had mentioned that he is trying to watch what he eats and drinks, trying to refuse the pintxos that are doled out to us. In a place like Gros, however, and with a job like Dani’s, that’s easier said than done.