If you’re in the Westminster area on an extremely hot day this summer, here’s a little trick: head to the Old War Office, now the OWO by Raffles and find Kioku Bar on the ground floor – an offshoot of the Kioku by Endo restaurant on the top floor. Ask to peruse the sakes; the “cellar” is really a compact and bijou chilled room behind a sliding door.

Once you’ve been in there and discovered the over 100 sakes, it would be rude just to leave, so this is a good excuse to settle in for the evening and explore the surprising variety that the fermented rice beverage offers. An impressive 20 per cent or so of the sakes are available by the glass. 

Kioku – meaning “memories” – is not solely a sake bar; it showcases Japanese whiskies and gins from Suntory and Nikka, among others. And a seasonally shifting array of cocktails (we’re currently in natsu, or “summer”) augments 12 permanent signature mixes, many using sake, sochu or other Japanese ingredients.

Kioku is also on a mission to educate us about sake. As interest grows, it’s clear most of us have a long way to go in understanding it as a drink. Step forward Natsuki Kikuya. Born into a sake brewing family, she is a sake educator and sommelier, and a member of the association of Sake Samurai! Having put together the sake list for Kioku, she now hosts a monthly masterclass in the bar, with a different guest brewer every time. 

These include master brewers she brings over from Japan, but also from nearer to Westminster. One such recent masterclass featured Tom Wilson from Kanpai, which launched in Peckham in 2016 (it has recently relocated to Bermondsey) and has built a reputation for its quality and a breadth of repertoire that would put most Japanese breweries (which often focus on a particular style) to shame. This year, its aged junmai sake, Kura, won gold at the International Wine Challenge, the first non-Japanese sake to do so.

Kanpai is often thought of as being experimental, but Wilson explained, ‘Some of our sake – in terms of method, ingredients, the equipment we’re using – is made more traditionally in our brewery than it would be in quite a lot of breweries in Japan these days. So sometimes we release something, and people say, “Wow, this is new, this is really cool.” But actually, we’re making something that would have been around 200 years ago. We provide something that is rarely available outside Japan – particularly when it comes to raw, unfiltered styles of sake that generally don’t travel very well.’

At one point during the tasting, we have three glasses in front of us that are so different, it’s a wonder they’re all the same drink – one milky white, one crystal clear and one the amber of an aged sake. Kikuya makes sure that whoever is featured in the masterclass brings some limited-edition bottlings and even some exclusive rarities (never is a tasting as exciting as when a bottle labelled with a Sharpie comes out!).

The next masterclass (Tuesday, 30 July) will feature another UK producer: the Sparkling Sake Brewery, based near Cambridge. As well as presenting different sparkling sakes, based on different moromi (the mash of rice, koji and yeast), they also offer a rare taste of a non-sparkling sake and a bottle exclusively for the Kioku masterclass. Guests are also offered canapé pairings created by Endo Kazutoshi himself.

The following month (Tuesday 20 August), the cultural exchange goes the other way. Briton Philip Harper is the brew master at Tamagawa in Kyoto – the only non-Japanese toji in the country. He will be in London, bringing with him some seasonal specials.

Kioku Sake Masterclass Series, episodes 3 and 4, take place on 30 July and 20 August respectively. Tickets cost £75, including a flight of six sakes and canapés. Book at kiokubyendo.com