"You leave it for anywhere between one to three weeks, depending on the temperature, then it's bottled and left for a day to get nice and fizzy, then it's ready to go."
Leibbrandt's husband made her a fermenter out of an old freezer and she brews in the family's garage, moving from small glass vessels to 10-litre food grade buckets as demand increased.
"I just love seeing something and thinking 'oh, I can do that for myself'.
"There's always a bit of experimentation, but that's all part of the fun."
After applying for a permit from the Whanganui District Council to sell to the public, Leibbrandt said she was able to supply Stellar Restaurant and Bar as well as running her weekly stand at the market.
"I'd love for other cafes and restaurants around town to try out the kombucha and potentially put it on their menus," Leibbrandt said.
Flavours include raspberry; ginger, turmeric and black pepper; blackcurrant and honey; and pina colada, and Leibbrandt said local eateries were "absolutely welcome to get in touch" and a free sample would be offered.
"The kombucha comes in one-litre bottles, and it's actually concentrated."
As well as brewing kombucha, Leibbrandt makes skin and hair products in bar form, under the name Bar Necessities.
"I only use essential oils for these products, and it's a great alternative to plastic bottles.
"I supply a few shops here in town, as well as in Taranaki and the South Island."
Leibbrandt said Bar Necessities products were available online, as well as at the River Markets.