My tonic habit is similar to my mid-week vs weekend wine buying. We stock up on litre bottles of supermarket-own fizz to top up our gins when it's just us, and splash out on more expensive brands when we have people over.

But if you really care about how your gin tastes – and let's face it, if you've spent over £30 on it, you probably should – could buying premium tonic be more important than we think?

"We've seen an increase in sales of premium mixers, driven by an increased awareness among customers about the quality of the mixers they buy, as well as the recent surge in gin sales," says Elizabeth Edwards, soft drinks buyer at Waitrose & Partners.

People are also buying more flavoured offerings, she says – grapefruit, orange and rhubarb being particularly popular.

"The 'Instagram effect' has a big part to play in customers choosing flavoured tonics," adds Edwards. "Colour is becoming a key consideration among customers seeking a visual experience, alongside amazing flavour."

RECIPE: Creme brulee with home-made shortbread

When you think of premium tonic, you probably think of Fever-Tree. Many of us enjoy drinking it, but is it worth paying so much more? Head into Asda and you'll find a bottle of the supermarket's own-brand tonic costs around nine times less per 100ml.

"Before Fever-Tree, the tonic water category was dominated by Schweppes who still, to this day, sweeten some of their products with artificial sweeteners like saccharin and aspartame," says Saskia Meyer, Fever-Tree's UK marketing director. "The impact these sweeteners have on taste is considerable. They leave a cloying aftertaste and often mask the flavour of the spirit they are mixed with. Fever-Tree was launched to change the status quo, putting the best quality ingredients back into mixers. The crisp, clean taste, combined with the other botanical flavours, enhance the flavour of the spirit. We've helped revolutionise the G&T globally."

Premium spirits continue to grow, and we seem to be drinking less, but better quality, so fancy tonics and mixers fit nicely into this trend. Most of your G&T is tonic, after all, so there's not much point spending lots of money on a beautiful craft gin, only to drown it with a poor-quality mixer that masks the botanicals and flavours.

"With the huge array of gins and tonics on the market now, the possible pairings are endless and can be quite overwhelming for consumers," notes Meyer. Indeed, Fever-Tree's pairing guide is one of the most popular pages on their website.

"As an example," she continues, "for a citrus gin, the pairing wheel will recommend our Mediterranean Tonic Water, which contains sweet, floral notes of lemon thyme and rosemary from Provence, whereas our Aromatic Tonic Water – which uses angostura bark from South America and pimento berries from Jamaica to create a sweet yet spicy flavour – is recommended to pair with juniper-heavy gins."

Supermarkets are getting in on the action now too. Co-op, Asda and Sainsbury's all sell their own premium versions of tonic, alongside their bog standard offerings.

"With over 360 distilleries in the UK, the tonic used to mix with the vast variety of gins on offer should be thoroughly considered, and not overpower the delicate flavours in the gin," notes Ash Luxton, Co-op senior soft drink buyer.

"Indian tonics and tonics with citrus and spice notes pair well with spicier-style gins, whilst an elderflower tonic is the perfect accompaniment for a floral gin. Experimenting with different flavoured tonics and a London Dry Gin is a great way to try new versions of the classic G&T, without splashing out on more than one gin."

And his top tip for preparing the perfect G&T? "Fill your glass to the top with ice and add a garnish; twist a peel of orange or lime over the top of the glass to spritz the oil into the drink, then drop into the glass. It will instantly make that drink feel a little more special."

TOP TONICS

1. Fever-Tree Indian Tonic Water, £3.20 for 4 x 200ml, Sainsbury's

2. Co-op Irresistible Blood Orange and Rosemary Tonic, £1.30 for 500ml

3. Fentimans Pink Grapefruit Tonic Water, £1.90 for 500ml, Waitrose & Partners

4. London Essence Co. Orange & Elderflower Tonic Water, currently £1.59 (was £1.99) for 500ml, Waitrose & Partners

5. Fever-Tree Mediterranean Tonic, £1.81 for 500ml, Asda