My Round: Long, strong and delicious chilled, iced coffee is the ultimate summer drink - or should that be dessert?

Well hello there. Are you going to taste as disgusting as you sound?" Don't worry – these words were not spoken to any living creature. I was addressing a sample of Ice Cappio, a new product from Kenco. Ice Cappio is a canned version of the iced-coffee drinks that have taken off in a big way since Starbucks began colonising the UK.

Why the rude question? Because the idea of pre-mixed iced coffee held all the appeal of a visit to the dentist. But I chilled it down and shared it with my coffee-loving daughter Alice, and shock horror: this stuff was genuinely decent. It is very sweet, and embarrassingly creamy, but in iced coffee, unlike most drinks, those qualities can be regarded as virtues.

At £1.29 for 200ml, Ice Cappio seems unlikely to find a place on the weekly shopping list. I liked the drink because it reminded me of the iced coffee of my youth, which was spent in a house where the only coffee was instant coffee. Instant finds its only useful purpose in the company of ice, whole milk and a tall glass. You make the coffee around triple strength with sugar to taste, let it relax to room temperature, then pour it over ice and stir in lots of milk. It isn't a bad drink.

If the instant version is useful, proper iced coffee is a thing of beauty. And with hot weather now in full swing, it is coming into its own. At one of my favourite London coffee palaces, the Monmouth Coffee Company's café/shop in Borough Market, they have taken possession of an ice machine and expect to sell cold drinks by the thousand. Their method: make an espresso, pour it over ice and add organic milk from Neal's Yard Dairy. I can't wait to get down for a taste.

At Monmouth they don't add sugar, though customers are free to wield the spoon as they see fit. For me, sugarlessness seems to transgress an implicit rule: good iced coffee should be bad for you. The drink makes me think of a quip I once heard: "Only Irish coffee provides in a single glass all four essential food groups – alcohol, caffeine, sugar and fat." I would say the same thing about iced coffee, minus the alcohol. Sugar and milk take the edge off. But only if the milk is whole – the fat taking on a creamily thick texture when chilled down by ice.

If iced coffee should be bad for you, its ultimate logical extension is the Viennese approach. There are several permutations, but the essence lies in filling the glass with as many calories as it will accommodate. At the Gloriette patisserie in Knightsbridge, for instance, Viennese iced coffee includes both ice-cream and whipped cream. This takes the drink to the border between beverage and dessert, which is a dangerous border to hike. Especially if you're drinking it with a pastry.

But the hybrid drink/dessert seems to be what most people have wanted since coffee-drinking Britain caught the Starbucks infection. After the Frappuccino came Costa's Gelatté and Coffee Republic's Freezer. Who knows what will be next? The aim: a thick, incredibly sweet coffee concoction that delivers Viennese-style richness without Viennese-style skill or quality. The means of acquiring it: standard mixes produced by other companies.

Jeremy Rogers of Espresso Essentials, which supplies mixes to Coffee Republic among others, says that the mixes are based on non-dairy creamer with added flavourings. "Larger chains have their own formulation because they want something that is unique to them, though they don't necessarily specify a flavour profile." A point to remember the next time you order your caffeinated pudding-in-a-glass? Could be. Personally, I'd rather make my own – even if Alice asks for another Ice Cappio. *