The hot chocolate at Mount Aso is made with Costa cocoa powder. Unlike the overly sweet versions you’ll often find in the UK (although the company is now owned by Coca Cola interestingly), this one is only lightly sweetened—which helps, a lot. It’s also made with local Aso milk, which helps even more. Thanks to those two things, this might just be the best Costa hot chocolate you’ll have anywhere.

Still, the real reason I’m writing about this drink is because of where I had it.

Mount Aso is the largest active volcano in Japan and one of the largest in the world. Its caldera, a vast crater formed by past eruptions, stretches roughly 25 km across, large enough to contain entire towns, farms, roads, an entire living landscape. At its center sits Nakadake, an active crater that still vents smoke. You can usually get surprisingly close, but not today; it’s closed due to heightened activity. 

A few minutes’ drive away is the main visitor hub beside the sweeping Kusasenri Grassland. While waiting for my drink, we down small bottles of Aso milk and watch plumes of smoke rise from the crater in the not so far distance.

Aso milk is surprisingly delicious. Worth grabbing a few bottles, as many people clearly do as the gift shop is full of it. It comes from cows raised within the caldera, grazing on grass grown in rich volcanic soil and drinking spring water. It’s pasteurized at low temperatures, preserving more of its natural flavor. It’s not just us who think it’s good, it’s won international taste awards.

Outside, the wind is strong and clouds rush past in waves. The scale of the landscape is so vast that the clusters of tourists look like tiny ants moving across it. The hills are an almost impossibly vivid green, rippling like water as the breeze passes over them. On the drive down, we spot a group of wild horses who are far less interested in us than we are in them.

If you have time, the Minami Aso Sightseeing Railway runs hourly, winding its way around the base of the mountain. If you’ve rented a car, and I highly recommend that you do, you can drive about 35 minutes to the Aso Milk Factory, passing the beautiful Ogi Rice Terraces along the way. About 30 minutes in another direction is Kokonoe Yume Otsuribashi, the highest suspension bridge in Japan, stretching 390 meters. Continue along the Yamanami Highway for some of the most stunning scenery in Kyushu.

Mt Aso Visitor Centre 1930-1 Akamizu, Aso, Kumamoto 869-2232, Japan