London, we have a problem. There's stuff we need to sort out together. It's exciting! But first can we sit down and have a great cocktail and some food and a chat? We'll get to that problem later.

This is how I think Ryan Chetiyawardana goes about his business. As one of London's most-loved bartenders and co-founder of Dandelyan, Super Lyan and White Lyan (now closed, more on which later) bars, he's always busy, and has a feast of ideas on what to do about the industry's most pressing issues. But first he'd like to ask how you are, and what you're excited about this week (he says 'exciting' a lot, which is infectious).

In her new book about whisky, author Rachel McCormack sums him up as 'the Ferran Adria [the founder of El Bulli restaurant in Spain] and David Lynch of the spirit world. No one is as thoughtful or as innovative as him in the drinks arena.

When he launched his brand, Mr Lyan, he had a cocktail of Talisker and oak leaf maturing in a salt-baked cask that he poured straight from the barrel into a glass. He has won every prize and every accolade that the drinks world can give him; mention his name to people in the drinks business and all they have are kind words and admiration.'

So we could end there, except there's news to share, and insect dim sum to discuss.

My previous interactions with Mr Lyan have included spending time in the Chelsea Physic Garden hearing about why it is that certain plants grow and taste the way that they do, and why that makes them delicious and interesting to use in drinks; and sitting down to sample menus of pre-batched (that's pre-made, allowing for fewer wasted ingredients) cocktails that take around seven months to research and launch.

This time I'm here to talk about sustainability, and about Cub, a new venue that he's launched on the former site of White Lyan on Hoxton Street, where with the help of a natural scientist they're growing all sorts of things "like herbs that won't taste like herbs when you try them." It's a partnership with Doug McMaster, his pal from Silo, the zero-waste Brighton restaurant, whose "inventiveness and character and the way he looks at things" Chetiyawardana is drawn to.

Mr Lyan has won every prize and accolade the drinks world can give him

Specifically Cub will be a bar-restaurant because "half of the stuff that we do for the bars is essentially kitchen stuff anyway," and the menu will include a range of experimental things like "Japanese knotweed, raw sheep's milk and ramson".

Their aim is first to provide "something comfortable and exciting that offers delicious food and drink and helps bring people together," and second to show that in 2017 "people have a skewed sense of value with food and drink. They see it as cheap, endless and throwaway… People have lost a sense of value towards [it]. We've sold out our food systems, and people don't seem to connect the dots of the issues of that. [With] Cub [we're] aiming to shine a light on this, and the fact that changing habits will improve the scenario. But we want to show that sustainability need not be about sacrifice, so we don't want to be too worthy or heavy handed with the messaging."

Great. So how do you go about creating something that feels fun and tells a story, but not like you're eco warrior-ing your way into the personal space of guests paying £9-£14 per drink (as at his other bars)?

"We didn't want any of the bars to be about recycled stuff [although incidentally Cub's bar is made out of recycled materials, but it's not necessarily obvious] – it needed to feel exciting and aspirational, and wonderful, and cutting edge, but still feel like something that people could participate in rather than being something for a certain elite or bracket."

Really, it's this approach that nails why Chetiyawardana has become so popular.

Ryan behind the bar

Looking at it another way, he argues that they're offering "what we think is really good value" not only because of what goes in on the research and development side, but also "the human aspect, too – all the people who are part of our project. Because we bring things in-house [they make nearly all of their spirits, syrups, vinegars and their no-grape 'wine'], and we take ownership of a lot of other things, we're fronting much of that cost, but we're still paying fairly all the way down that line… That sounds throwaway, but it's not universal."

To Chetiyawardana, something like staff wages is not so much about best practice or sustainability, but about doing something that's blooming obvious.

"It's like equality and feminism that shouldn't exist as words. [What they stand for] should just be the norm, but it's not, so it needs words to stand up for it… I think without people knowing that they want [sustainability], they do want it, because it's a very universal thing, and it affects everybody."

We want to show that sustainability need not be about sacrifice

In spite of this, he's "amazed" by how quickly "the sustainability stuff" has gathered momentum, "because it has not been that long a conversation, really."

So what of people catching onto sustainability as a trendy thing? "Hey, if sustainability becomes a trend, then it becomes less stigmatised, and more universal, but in any case I think that people will connect with the ideas for different reasons. I've said that we live in a bubble [doing this] to a certain extent, but we're also reacting to what's happening in the world. Food and drink is a reflection of a larger societal cultural shift, and I think people are caring more… I don't think that the modern world wants to give up having bananas, or travelling all over the planet. What will make more of a difference is if people make more demands and are more considerate about what they choose to buy."

Talking of caring, I ask Chetiyawardana, who grew up with Sri Lankan parents in Birmingham, enrolled briefly at its College of Food before studying philosophy at the University of Edinburgh and doing bar work on the side, whether these things have always been important to him.

"We grew up in the kitchen, partly because mum was a chef at one point and because it was an important part of the family life, bringing people together through food. So eating everything that we had was part of what we did, but also because we didn't have a lot of money, so you didn't waste things… It doesn't make sense. I always think that mentality is like charity. It doesn't matter what your motives are but the motives for me are moral and ethical."

If foraging became globally adopted we wouldn't have any wild food left

Really, though, his bigger ideas formed later on in 2010, following work at Edinburgh's Bramble bar, and later London's vaunted 69 Colebrooke Row and Worship Street Whistling Shop. Chetiyawardana was gradually developing the concept for White Lyan and becoming increasingly aware of how "stuck in its ways the industry was, and in creating this idea that just because something was luxury it had to be wasteful…"

At this point he remembers a project called Lunch in 2050 that he worked on with Shay Ola, the founder of creative food events company the Rebel Dining Society.

Having decided to serve an insect burger to go alongside Chetiyawardana's lecture, Ola suggested that they actually did dim sum instead "so that it wouldn't be presented as insects, but just as something delicious."

And then he veers off to imagine something else: "The thing is, the small initiatives are amazing, especially the ones that get people excited or remove stigma, but actually if foraging became globally adopted we'd have no wild food left. Something like that is wonderful for educating people and talking about the breadth of flavour and genetic diversity out there, but it would actually be difficult if it became a mass trend. I see it more as an educational thing… It really all needs to be led from the industry down – nobody would know if you switched out 50% of the protein in a McNugget [for insect protein]. That's a mass idea. And it really excites me. Imagine that!"

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