They were right, I was wrong: The best thing to do on a Saturday morning is to devour a St John doughnut AND sip a Monmouth Coffee. The two sensations originate seconds apart. Monmouth’s roastery (map), entered on the Maltby Street side of same railway arches, is open to the public on Saturday’s from 9am to 2pm for savoring great coffee and killing sweet time. You can purchase beans, too.

You can be forgiven for thinking there ‘s cream inside a silky-smooth Monmouth latte, as there is in a St John doughnut. One way Monmouth leads the top 10 coffee shops in London is by using organic Jersey whole milk from Jeff Bowles in Somerset in its silky-smooth lattes. Their richness helps wean you off the custard doughnuts.

It was past the morning rush and my pre-caffeinated eyes coasted halfway through the coffee menu at Blue Bottle Coffee ‘s new Brooklyn roastery before getting stuck onto a road barrier listed only as SG-120. I shifted my gaze into reverse, spotted the familiar signposts espresso and macchiato and tried to make use of all available evidence: If, as I suspected, SG-120 referred in some way to a Japanese video game console, what made it worth an additional 25 or 50 cents?

The barista, bless her heart, did not roll her eyes when I asked her to explain the connection between sega genesis and espresso, nor did she make a joke about it being a tattoo removal cream. The SG-120, she explained, was the model number of the small, delicate Japanese glass in which Blue Bottle served its single-origin mini-lattes. (So I was right: it was Japanese!) Whereas the similarly proportioned coffee made with Retrofit, the house espresso blend, is called a Gibraltar, after the classic Gibraltar glass, those made with beans from a single growing region – in this instance Kintamani, Bali – took the shape and name of a different receptacle.

The SG-120 is printed on the Blue Bottle menu, unlike the unlisted Gibraltar, but it too enjoys a cult status and purposefully obscure origins. Excitedly unpacking a large shipment of brewing equipment and supplies from the highly respected and now wildly popular Japanese glassware company Hario at Blue Bottle’s location in San Francisco’s Mint Plaza (see map), owner James Freeman and his colleagues discovered that the pieces they’d ordered as water glasses were much too small and delicate for that rough-and-tumble purpose. (They probably wanted the SG-300 rock glasses or HPG-300 tumblers). The Hario SG-120s are amongst the world’s lightest, thinnest-lipped, shortest-bottomed shot glasses. They’re perfect for sake.

So what does a coffee bar do with dozens of ethereal sake glasses it can’t use? Freeman observed their 120-millitre (about 4oz) volume was roughly equivalent to that of the Gibraltar glass he was using and thought the SG-120 could be employed to visually differentiate the single-origin Gibraltars from those made from an espresso blend. His wife Caitlin inspected the boxes of Hario glasses and suggested they name the drink after the model number printed on them.

“We couldn’t call it a Gibraltar because it’s not in a Gibraltar,” says Freeman. “That would be wrong.”

An early review of the SG-120, from TheShot, a San Francisco-based coffee blog, was unfavourable: “It felt cheap and almost disposable, and its thinness and materials added no real thermal properties.”

Fair enough. That view, however, overlooks an elegance and simplicity that adds refinement to a quarter-pint latte. When you look at the SG-120 from the side it appears to float. Instead of the liquid taking its shape from its container, your impression is of a glass taking its shape from the swirls of textured milk and espresso within it. Moreover, if the glass is too hot to hold, that reflects a problem with the SG-120’s preparation: The milk should never be that hot.

My affection for the SG-120, especially now that I know what it is and know that it’s safe to drink, is shared by Blue Bottle habitués on both coasts.

“It’s the most stolen item in the shop,” boasts Freeman.

“Actually there are no good waves in Wellington,” says chef Miles Kirby (at right in photo), co-owner of Caravan, a new restaurant roastery on London’s Exmouth Market.

“Bit cold in Wellington for surfing,” adds Chris Ammermann, Kirby’s partner and fellow expat.

Who knew?

Perhaps thwarted in their search for surging breakers between the banks of the Thames, Kirby and Ammermann have caught another kind of Antipodean-ridden wave – the third wave of coffee in London. They’ve installed a 10-kilo coffee roaster in the basement of Caravan, making it the first restaurant in the UK to also practice trade as a coffee roaster, shop, retailer and wholesaler.

Caravan has already made world-class coffee connections. Kirby and Ammermann source their green coffee beans from Mercanta, a leading importer of speciality coffee, and rely on a champion-calibre barista to extract their most desirable characteristics. Caravan’s coffees, once roasted and rested, are brewed in-house on Tuesdays, Wednesday and Thursdays by 2010 UK Latte Art Champion Neil Le Bihan of Exchange Coffee.

Kirby’s approach to both food and coffee is global. As chef or roaster he’d never limit his inspiration to a single continent. His favourite coffee of the moment is the Rwandan Musasa Cooperative (red bourbon varietal). Its tropical fruitiness informs Caravan’s Brazilian-anchored espresso blend (and Le Bihan’s hanging tulip latte) yet is best appreciated on its own, as filter coffee slowly cooling in its cup. The flavours evolve.

From late morning through lunch, the Caravan coffee experience is influenced by greasy, smokey fumes blowing into the restaurant from the sausage stand directly out front on Exmouth Market. Kirby and Ammermann applaud the improvised fusion. Downstairs, another unplanned mingling of cooking vapours is taking place. Air currents push the exhaust from the coffee roaster back towards the kitchen and its sizzling frying pans.

How would Kirby feel if his cooking oils absorbed the roasting fumes, imparting coffee notes to falafel and soft-shell crab as they fried?

“If it happens,” responds Kirby, philosophically, “great!”