By Nikki Bezzant
There's a new fizzy drink in town, and it has an ancient past.
Kombucha - fermented tea - has emerged from the kitchens of health food enthusiasts to cafes and trendy restaurants around the country.
Around the world kombucha, and all things fermented, are hot.
Fermentation has been around for thousands of years. Traditionally it was a means of preservation; a way of keeping food safe to eat in the days before refrigeration and other food processing.
Most cultures have traditional fermented foods, including New Zealand - kaanga wai is fermented corn (sometimes called rotten corn) which I've never tried, but is reportedly delicious.
Fermented foods are catching our attention on the back of rising interest in the health of the gut, and specifically the bacteria that lives there. Gut bacteria are part of our microbiome; our individual populations of bacteria which can affect many aspects of our health, from our weight to our mental health.
Fermented foods and drinks contain probiotic bacteria, which may have beneficial effects on our gut bacteria, and so influence our health for the better.
Alongside kefir, sauerkraut and kimchi, kombucha is becoming more available and popular.
It's relatively easy to make yourself, at home, if you can get hold of a SCOBY (the unfortunate acronym for symbiotic culture of bacteria and yeast, the starter you need to kick off fermentation).
Aside from that, all you need is tea and sugar. The resulting drink can be flavoured with fruit or herbs, and is slightly fizzy. Commercial kombuchas are available in cafes, health food stores and some supermarkets.
Although it's been used as a health drink for centuries, hard evidence of any benefits from kombucha is scant.
There are animal studies showing kombucha may be effective in lowering diabetes risk, and may have cholesterol-lowering effects. There have not been any clinical trials on humans, to date, on kombucha's benefits. That doesn't mean it's not good for us; just that it hasn't been studied.
Experts say drinking kombucha will at least give us the benefits contained in the green or black tea with which it's made, which includes antioxidant polyphenols.
I enjoy kombucha as an alternative to alcoholic and non-alcoholic sweet drinks.
It can be a nice drink to have when you don't want alcohol; something to look into if you're partaking in Dry July. It's also a good one to try instead of other sugary drinks and juices, as it should be low in sugar. (Although made with sugar, most of this is fermented away).
Make sure you check and compare labels, though, as the sugar content can vary in commercially-available kombucha. The best ones have little to no sugar, meaning they're low in energy, too.
It's probably a good idea not to go crazy on kombucha, though, for the sake of our teeth.
Dentists say that just like other fizzy drinks, kombucha is acidic and can harm tooth enamel. So chase it with a water, and leave it half an hour before you brush.
Niki Bezzant is editor-at-large of Healthy Food Guide.