Portland is famous for its coffee and craft beer culture, but the tea scene is gaining ground. Katie Wright finds out what's brewing in the city.

Have you ever wondered, while making a round of PG Tips at the office, how tea bags are actually made?

Travel to Portland, in the US state of Oregon, and pull up a pew at the long, grey stone bar at Steven Smith Teamaker to find out.

Through the vast glass pane that separates the tasting room from the processing unit, you can watch as fragrant leaves are fed into a stainless steel machine that whizzes and whirrs until neat silky sachets are coughed out one by one at the other end, ready for boxing and shipping - to restaurants around the Pacific Northwest or as far as China (yep, where some of those leaves originated) and Japan.

Founded in 2009 by the region's legendary tea authority, the late Steven Smith, the eponymous outfit was the last of Smith's ventures, following the sale of his Tazo brand to Starbucks some ten years prior.

About 40,000 servings of tea are produced every day at the bright, high-ceiling space on the city's Eastside, the aim of which, head teamaker Tony Tellin explains, is "getting the public in direct contact with the maker".

As well as 40 ready-to-steep teas to choose from, there are a handful of 'nitro' varieties available on tap, a carbonating process that results in a smooth, slightly fizzy chilled brew.

The chai is subtly spicy, creamy and delicious.

For my main course, if you will, I opt for a four-cup 'flight,' which comes beautifully presented with little pots of the leaves to sniff and a spoon to sample each steaming cup.

The Portland Breakfast, a gutsier, earthier cousin of the English classic, is particularly satisfying, while the delicate Honeybush (like South African rooibos only lighter and fruiter), is wonderfully refreshing.

With its Scandi-chic interior and young, trendy staff, Smith's represents the cutting edge of the tea scene, but there are more traditional ways to get your Camellia Sinensis fix in Portland, as I discover when I spend a few days criss-crossing the Williamette river in search of a decent cuppa.

And I'm not disappointed.

From the hipstery Eastside joints to cool Downtown eateries (on the west) and several oriental gardens, there are enough tea dispensaries in PDX (as locals call the area) to keep even the most ardent caffeine addict buzzing for days.

That's particularly true if you opt for a matcha latte, in which the entire tea leaf is ground and dissolved in milk - meaning a much stronger caffeine hit (tempered by all-important tannin for a less jittery high) but also a massive dose of health-boosting antioxidants.

Then there's kombucha - a slightly fizzy, fermented, cold tea drink that's supposed to do great things for your gut thanks to its probiotic qualities.

Popular tea chain Townshend's makes its own in house, called Dr Brew Kombucha, in ten tasty flavours like Citrus Hops and Spiced Apple, but if you're after something a bit stronger look out for the brand's other off-shoot, Thomas & Sons Distillery, which creates spirits out of tea.

That's right, it's not just about a steaming pot of builder's round these parts.

Portland is a veritable tea-topia, so if you're going to hit up the city in search of good old Rosie Lee, here's where you should head...

Portland's top tea hotspots

1. Steven Smith Teamaker

Head to one of the two tasting rooms to embark on a 'flight' of four teas for $10 (about £8), choosing from a 40-strong list of white, green, black, herbal and oolong varieties. Shop for loose leaf or tea bags to take home, and find out what cold, fizzy 'nitro' teas are currently on tap. Visit smithtea.com

2. Tao of Tea

Tao of Tea has three Portland locations, the prettiest housed in the Lan Su Garden, a little pocket of tranquillity in the middle of China Town. Eight different taster flights, comprising between three and five Chinese teas each, are available, starting at $14 (about £11). Visit taooftea.com

3. Kashintei Tea House

Nestled in the newly reopened Japanese Garden, in this beautiful authentic tea house you can witness an intricate 'Chado' (tea ceremony) while seated shoeless on the traditional tatami mat floor. The ceremony takes place every Wednesday at 5pm, with the price included in admission to the Japanese Garden, which is $14.95 (about £12). Visit japanesegarden.org

4. Afternoon Tea at Hotel DeLuxe

English-style high tea at the classy hotel comes complete with finger sandwiches, scones and bite-sized baked goods, all with a Portland twist (like jam made from Marionberry, the fruit engineered in Oregon). Teas, including custom blends, are courtesy of Smith's. Prices start at $39 (about £31) per person, bubbly and tea-infused cocktails are extra. Visit hoteldeluxeportland.com

5. Townshend's

With comfy couches, a cosy atmosphere and a plentiful Wi-Fi, no wonder Townshend's (the 'h' is silent) four teahouses are among Portlandians' favourite places to work, chat or chill out. The 100-plus varieties on offer make it an essential stop on any tea connoisseur's route through the city, too. Prices start at $2.50 a cup (about £2). Visit townshendstea.com