Pineapple water kefir

By Nik, founder of 東歐嚴選｜kefir.link and former chef · Updated 2 November 2026

Pineapple water kefir is a cold summer drink: a fruity, sour fermented base brightened with sweet pineapple juice and poured over ice. Water kefir is made by fermenting sugar water with water kefir grains, whose microbes produce its acids and carbon dioxide. The pineapple juice gives those microbes fresh sugar, so the flavour keeps developing in the bottle.

Not the same as Mexico's tepache

Mexico has its own fermented pineapple drink, tepache, which dates back to before Columbus reached the Americas. Its name comes from a word in the language of the Nahua people for what was originally a corn drink. Today tepache is made by fermenting pineapple rind with brown sugar, and street vendors sell it cold. Pineapple water kefir starts differently, because its base has already been fermented with water kefir grains and the juice is added afterwards for flavour.

Why the grains come out before the juice

Fruit juice can stop water kefir grains growing, break them down and stain them, so the juice goes only into finished, strained water kefir. The microbes left in the drink keep feeding on the pineapple sugar and making gas, even in the fridge, where fermentation slows but does not stop. That is why the drink goes into pressure-rated bottles with space at the top. How much fizz you get depends on how active your water kefir is, and a leaking cap lets the bubbles escape.

Fresh pineapple, ginger and other twists

Fresh pineapple chunks or a whole pineapple rind can flavour water kefir instead of juice, and the fruit is strained out before serving. Ginger adds an earthy spice to sweet, tangy pineapple, and fresh grated ginger tastes stronger than candied ginger, so start with a little. You can also pair pineapple and kefir with fresh mint or basil, or add coconut milk for a drink in the style of a piña colada.