In the cool, brick cavern of Corks Out, a wine merchant in the basement of one of Chester's Rows, we're trying two white English wines: a blend of Bacchus and Schönburger grapes, and a Sauvignon Blanc.
The first is by Denbies, a leading producer of British wines. "There's a lot of fruit in the nose – almond, wild strawberry ..." suggests our expert taster, Peter Stephens, who looks after buying for the independent store.
The second, the Sauvignon Blanc, is by Worthenbury Wines, a little-known vineyard that takes up an acre of land behind the home of Martin Seed, a retired regional manager for Marks & Spencer.
"This has a lack of fruit and a lot of alcohol coming off it," says Peter, taking his first sip. "But there's great balanced acidity, zippy lime, hedgerow notes. It would be good with food. And the structure is good."
Peter isn't just trying to help me understand the Worthenbury wine, Corks Out is thinking about stocking it. He seems surprised at the quality achieved with a grape that he believes is an ambitious choice for this area.
But he's still not too happy that the vines are cultivated in polytunnels – he prefers grapes to embrace the sun. And he's also yet to discuss the volume the shop can buy and assess whether the price is marketable.
Down the road at the award-winning hotel The Green Bough, owner Philip Martin tells me that he is keen to keep things as local as possible – we are lunching in his restaurant, the Olive Tree, on produce from nearby Hoole and Delamere.
He likes the idea of a local wine and buys about 500 bottles of Worthenbury a year for the wine list. "People like to try it on the basis 'I've never heard of Welsh wine before,'" he says.
Hang on a minute, Welsh wine? My mission is to visit Cheshire's vineyards. It seems Worthenbury Wine comes from just a few miles over the county's western border, in Denbighshire.
But surely we can turn a blind eye? The weather there is largely the same and what is extraordinary is the fact that grapes thrive in this area at all. Caroline Hoppé of Visit Chester and Cheshire, my guide for the day, is certainly undeterred by this inconvenient fact and, anyhow, she has more to show me.
Our next stop is to see a vineyard in the grounds of a private home, Long Acre, in the Cheshire village of Bunbury. Margaret and Michael Bourne first planted the German varieties Bacchus and Phoenix in their garden five years ago, bringing in a harvest a couple of years later.
Despite the unwanted attention of mildew and badgers, the vines have made a respectable wine and, while it is for family consumption only, the project is inspirational for the garden enthusiasts who call by twice a year when the Bournes take part in the National Garden Scheme.
A few miles south-west, still within Cheshire, we find vines being growing for commercial purposes at the De Vere Carden Park Hotel. There have been vines here since 1989, though they were abandoned a few years ago and are only now being nurtured again under the orders of the hotel's owner, Steve Morgan.
Peter Pattenden, the hotel's golf and estates manager, shows me one of the two plots where they are growing two varieties of Seibel. It won't be long before they have the white sparkling wine back in production, he says. It will be sold in the hotel restaurant and the hospitality rooms at Wolverhampton Wanderers, for which Mr Morgan is rather better known – he's the football club's chairman.
With a little help from global warming, it can only be a matter of time before those French vineyard owners who are snapping up swathes of Sussex turn their attention further north.
How to get there
Virgin Trains (08457 222 333; virgintrains.com) offers fares from London to Chester from £13 single.