Why people are crazy about Blue Bottle, the coffee chain that just raised another $70 million from tech investors

High-end coffee retailer Blue Bottle Coffee, a favourite of the tech community, has

received an additional $US70 million in funding from several big-name tech investors and Fidelity Management and Research.

Tetragon Financial Group, Morgan Stanley, Index Ventures, True Ventures, Bono, Jared Leto, Tony Hawk, and Instagram founder Kevin Systrom contributed to the round.

The company, which operates 19 locations in New York City, California, and Japan, has become hugely popular with hipsters and techies from coast to coast. Vintage brewing machines and artisanal coffee are some of its major selling points, and lines are known to get long.

The chain previously raised a $US25 million round in January 2014, with contributions from Morgan Stanley Investment Management, Twitter cofounder Evan Williams, VC Chris Sacca, and WordPress cofounder Matt Mullenweg.

Last year, we paid a visit to the spacious Blue Bottle cafe in Williamsburg, Brooklyn, to see what the hype is all about.

We visited Blue Bottle's Brooklyn shop, located on a pretty nondescript street in Williamsburg. The cafe is housed in an early 20th-century brick building that, according to Blue Bottle's site, was at different times used by glass blowers, metal smiths, and barrel makers.

We got our first glance of their famous Blue Bottle logo right at the entrance. The logo on a to-go cup is part of the company's cachet and a sure sign the drinker is 'in the know' about what's cool in the world of coffee.

Guests were sipping coffee and reading the newspaper at the counter when we visited in the late morning.

More people congregated at this long table in the middle of the room.

There were a lot of people around, but the cafe was laid-back, and mellow music played over the speakers. We missed the morning rush, when lines can build up.

We snuck a peek at what was going on behind the counter. The company prides itself on unique brewing techniques, and the Williamsburg location uses a vintage Probat roaster, Kyoto-style iced coffee drippers, and a restored Faema Urania lever espresso machine.

The menu is pretty straightforward, with one size and price for each drink.

Behind the counter, baristas manage a drip bar that's seven cups long.

They all bear the Blue Bottle mark, too.

Coffee isn't Blue Bottle's only product. You can buy granola in to-go bags or choose from the baked goods in this case behind the counter.

But there's also a lot of gourmet stuff to look at on the counter, including these Mast Brothers chocolate bars, also from Williamsburg.

Olive oil shortbread and ginger molasses cookies are just a few of the appetizing options.

According to Blue Bottle, this restored Faema Urania lever espresso machine dates back to 1958.

To start, we decided to try the New Orleans iced coffee and the Buckwheat Buttermilk Biscuit Sandwich.

The biscuit was one of the best coffee-shop pastries we've had, a savoury combination of sweet and salty flavours.

The New Orleans was sweet, served cold with milk and sugar.

Next we decided to try some espresso (left) and drip coffee (right). Helpful labelling on each package of coffee lets you know what kind of beans are inside, including where they're from and whether they're Fair-Trade certified.

The barista put the finishing touches on the espresso drink.

The espresso, a fruity Ethiopian variety, came out beautifully.

Our drip coffee was almost ready.

The barista told us that this coffee, which also came from Ethiopia, would best be enjoyed black. It came served hot in a glass mug and had a light floral taste, almost like a tea.

If we'd ordered our coffee to go, we would have gotten it in one of these trendy brown cups.

These funky-looking machines are actually slow cold-drip coffee makers from a Japanese company called Oji. They're used to make Blue Bottle's Kyoto iced coffee.

The five globes and filters are situated among a collection of coffee knick-knacks opposite the counter where we ordered.

There's plenty of merchandise for sale, like this Hario Range Server that retails for $25.

Just beyond, you can get a quick glimpse at the roasting process.

Sacks of coffee beans sit on shelves in the back. The staff explained that they roast small batches at a time, equivalent to about half of one of these bags.

Every day, they process the beans on this vintage Probat roaster, a very precise procedure that requires a lot of concentration. Beans are served within 48 hours of roasting, which guarantees their freshness.

Employees have to pass rigorous training before they begin work at a Blue Bottle cafe.

Small, simple signs with faux handwritten font prohibit smoking in the cafe (and offer a number if you're looking to quit).

Similar signs encourage you to recycle before you exit.

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