Dach, who is German, is a knowledgeable Pimm’s aficionado who learned to love the drink during a long sojourn in England, although he first encountered it while at hotel school in Switzerland.

“I was invited to visit a British family who were living in Geneva at the time, and one of their summer parties was the first time I tried Pimm’s and [commercial] lemonade,” he recalls.

One of the strengths of the classic gin, herbs and liqueur combination, he points out, is that it is almost infinitely adjustable to personal taste, depending on what you mix it with.

“Personally I like it made with cucumber, orange and mint. Those are the basic things it needs. And I top mine up with a dry apple cider – Bulmer’s for example – and Sprite. I don’t like it as sweet as it would be with only Pimm’s and lemonade. Ginger beer or cider counter the sweetness of the Sprite. They make it just a bit less drinkable. If it’s just Pimm’s and lemonade, outside on a hot day a glass lasts me less than five minutes. It’s just too easy to drink. We’ve featured it in a jug mixed with Crabbie’s Ginger Beer, and that went very well. A lot of people liked to drink that outside on the terrace.”

Pimm’s was originally developed by City of London oyster house owner James Pimm who began offering it in 1823 – served in tankards as it is today in the Captain’s Bar at the Mandarin Oriental.

The early popularity of the original Pimm’s No.1 formula led to the development of several others using different spirit bases, although none was quite as successful.

“Pimm’s classically has six variants – there’s a gin-based version which is No.1, then there’s a scotch-based version which is No.2, brandy is No.3, rum is No.4, rye whiskey No.5, and No.6 is vodka,” explains Dach.

Several of these have gone in and out of production at various times, and some are currently unavailable, or available only in small batches in the UK market.

Generally speaking though when somebody orders a Pimm’s, it’s the No.1 version they expect to be served.

Pimm’s can be presented as more or less a fruit salad in a glass, but some find that approach a bit too cluttered, and prefer to garnish the drink with nothing more than a slice of cucumber, and perhaps a maraschino cherry. Another, more modern, approach is to serve it topped with a bunch of basil in which the drinker has to bury his or her nose.

“As long as fresh fruit is used I don’t find it cluttered,” says Dach. “There are hardly any fruits that don’t go with Pimm’s. I’ve had it served with banana, with peach, with pear, with apple – all these fruits add something. Where I draw the line is adding liqueurs – although Pimm’s itself has done that. It brought out Pimm’s and strawberry, Pimm’s and cassis, but that adds sugar, so for me that’s over the top.”

For those who prefer a less herbal taste – and a little extra kick – Dach recommends fortifying the drink with a little extra gin. No.1 is bottled at 25 per cent alcohol by volume.

Pimm’s can be topped up with soda or tonic water, as well as the mixers Dach mentions, but for a sense of occasion nothing beats champagne.

That combination is usually called a Pimm’s Royal Cup, a Pimm’s Royale or a Pimm’s Royal, but at ToTT’s it’s called a Pimm’s Royal.

“We use a 5cl pour of Pimm’s, muddle it with fresh ginger, some lemon juice and a bit of sugar and then top it with the sparkling wine or champagne. We use highball glasses because it’s served over ice, and champagne glasses are too small,” says Dach.

The drink is garnished simply, with slices of ginger and cucumber, and a cherry.

Customers can choose whichever bubbles they prefer, but Dach suggests the house champagne, which recently switched from Veuve Clicquot Yellow Label to Moet & Chandon.

“I think topping with a house champagne is very nice, but I wouldn’t use a vintage champagne because I don’t think you could taste it through the Pimm’s. The idea really is to taste the Pimm’s, not the champagne,” Dach says.

Three of the best places to find a Pimm’s in Hong Kong

Pimm’s isn’t hard to find in Hong Kong bars at this time of year, but these three are among those that serve it particularly well.

ToTT’s 34/F The Excelsior Hotel, 281 Gloucester Road, Causeway Bay, tel: 2837 6786

Lobster Bar and Grill 6/F Island Shangri-La, Two Pacific Place, 88 Queensway, Admiralty, tel: 2820 8560

Captain’s Bar Mandarin Oriental, 5 Connaught Road Central, tel: 2825 4006