It's a treat best served cold.

And the newest trend to hit the coffee world is causing a buzz in Norwich.

Cold brew coffee is becoming increasingly popular across the city, with independent traders and the big chains alike serving the trendy take on a cup of joe.

The drink is steeped in cold water for 20 hours without any heat, which supposedly creates a far smoother taste than an iced coffee, along with allowing for more variable and sweeter flavours.

One fan is Alchemista Coffee Potions, a new shop in the city who use their own unique slow drip coffee machine.

Vicky Brown, co-owner, said customers were increasingly asking for cold brew.

'As a new business, it's too early to identify trends, however I do think there is a trend for cold brew in Norwich and it has proved to be a popular choice during our first month of trading.'

But Kieran Harper, owner of Artel, is not so convinced with the results of cold brewing.

'Lots of people ask for cold brew when it gets hot,' he said.

'I think the general quality of cold brew coffee just isn't anywhere near that of the hot stuff and you just don't get the same complexity of flavour from cold brew.

'If I don't fully back something and I'm not proud to serve it, I wont serve it.'

Jose de Leon Guzman, owner of Kofra, said cold brew was a 'versatile' drink.

'I wouldn't say it's more popular than other coffees, but it's here to stay.

'Summer is long gone and we're still selling lots of it. In fact, it's now part of our main menu.'

The mainstream coffee giants, Costa, and Starbucks are already serving cold brew, with Caffe Nero expected to follow.

Baristas are also adding a flourish to the coffee with the addition of 'nitro'.

'Nitro' cold brew coffees, so-named because of the infusion of nitrogen, are intended to give a smoother taste than the original cold brew, which is more akin to a beer than a coffee.

The coffee is often even stored in kegs, ready to be poured from a draft tap.