Forget craft beer and gin - this is one of the next big epicurean trends

If you'd asked me before I joined Trafalgar's Best of the Rhine and Amsterdam river cruise what I expected the highlights to be, a vinegar tasting wouldn't have ranked in the top 10. I was wrong.

Small-batch, artisanal vinegar is one of the next big epicurean trends, prized like fine wine by top chefs and adventurous home cooks. If you know you know (I did not know) that cheap supermarket vinegar takes less than an hour to make. The good stuff can take three decades or more.

"Please don't consume the vinegar you buy in the supermarket," says our guide at Weinessiggut Doktorenhof, a private artisanal vinegar estate. "It has its function if you want to clean something, but don't be putting it on your salad."

The estate is located near the Rhine River city of Speyer in south-west Germany's Palatinate wine country, a short bus ride from where our ship, Trafalgar Verity, is docked. The visit is one of Trafalgar's signature "Make Travel Matter" experiences, promoting sustainable production and eco-friendly farming practices.

To call Doktorenhof a vinegar factory would be a massive misstep. Carrying on traditions passed down through generations of the Weidemann family, it's a sanctuary dedicated to what has been dubbed "sour wine", a place where the slow-aged elixir is carefully made and mindfully tasted.

The first part of the tour requires a bit of theatrical dress-up. Each of us is handed a heavy, hooded velvet robe to wear. Looking like a cross between extras on the set of Eyes Wide Shut and Gregorian monks, we descend into a candlelit, subterranean cellar.

The air is thick and cool, heavy with the aroma of fermenting grapes and pungent herbs. Rows of aged oak barrels line the walls, holding within them premium local riesling and pinot noir that's left to sour naturally over many years.

"We take our time here, there's no rush," says our guide. "Everything is done by hand and the product is completely organic. Yes, we are more expensive than Costco; you're paying for the knowledge, the love, the time it takes to do it right."

Next stop is a seated tasting, an opportunity for our palates to explore. Waitresses hand out small pours of vinegar in custom-made flutes, encouraging us to swirl, sniff and taste as we would a fine wine.

Forget the harsh acidity of a cheap vinegar: the first sip is sweet, made with local figs that have grown in the region since the Romans brought them here 2000 years ago. The next, my favourite, compares to a fine, aged balsamic that I would love to spritz all over air-fried Brussels sprouts. We try a rich, dark digestif infused with wild berries and chocolate, and a therapeutic herb blend crafted to boost digestion.

It's almost time for us to rejoin the ship, but not before a visit to the gift shop. Artisanal vinegars are loaded into baskets faster than you can say, "Yes, this small bottle is absolutely worth the $30 price tag."

The writer travelled as a guest of Trafalgar. Explore more: doktorenhof.de; trafalgar.com