23g water kefir crystals
80g sugar
1000g water
5 sultanas or other dried fruit (optional)
Juice of 1/2 lemon (optional)
If the water is soft, some calcium (¼ tablet)

Dissolve the sugar in cold water and add all the ingredients.

Rinse the water kefir under cold water and remove any dried fruit. Rinsing is only necessary the first time it comes into your home.

Cover the jar with kitchen paper and a rubber band and leave the kefir to ferment for 2-3 days. It is quicker in summer than in winter. The longer you ferment, the less sweet the water kefir will be because the crystals have already eaten away the sugar. But: too long also means that there is more alcohol (max. 2-3%) and no residual sweetness, you have to test this out.

If you use dried fruit, fish it out; if you use ready-made water kefir, it will float to the top.

Pour the finished drink through a plastic sieve (kefir supposedly doesn't like heavy metal, but see below) and collect the crystals for the next round.

After the 1st fermentation with the ‘starter’ it has already multiplied a little.

If you want to make lemonade, start the 2nd fermentation (I use beer bottles with a pop top):

200 grams of fruit to 300g of water kefir - liquid not the crystals.

Pour the pureed or juiced fruit (or juice) into bottles and top up with water kefir. Leave to ferment for 1 day at room temperature without closing the lid, just put it on so that nothing can fly in. Then put it in the fridge for 1-3 day(s). Be careful when opening, it could bubble or even ‘explode’ - always open carefully in the sink with a cloth over it and release the gas. :)

2. fermentation experience

With the finished water kefir in a screw-top jar for 1 day at room temperature with the lid on and then a day in the fridge, no carbon dioxide developed in my case. All without adding anything else. Even after a longer period of time, no carbon dioxide develops.

With 200g of sour cherry juice to 300g of water kefir, I had a wonderfully sparkling lemonade. The longer in the fridge, the less sweet the lemonade is.

Maybe don't fill the bottles completely so that you can release the ‘vapour’ more easily.

If you're not so keen on ‘tingling’ or can't tolerate it, but still want a great mouthfeel:

pour the standard kefir ice cold into the iSi™ Nitro.

Pour the standard kefir with juice into the iSi™ Nitro ice cold - without 2nd fermentation.

Unfortunately, the soda will not keep for long as the sugar will continue to be absorbed. In my case, there was no residual sweetness after just 1 week and the lemonade became very sour.

My attempts

Store the kefir pure in the fridge and only make the lemonade 2 days before consumption.

Dispelling the metal myth

Plastic strainer - the drink has been around for ages - there was no plastic strainer back then. Ok, at first you might have passed through cloths. But stainless steel shouldn't be a problem, it's corrosion-free and the same applies to aluminium.

A little tip for swing-top bottles

I organised an empty crate of beer bottles with swing tops at a drinks store, washed and sterilised the bottles. For a whole €4.50. They are also protected from light :). Alternatively, buy a full crate and drink the beer.

Pause water kefir

Mix sugar with water (in a screw-top jar) 1:4, stir until the sugar has dissolved. Rinse the crystals and add to the sugar solution. The crystals must be covered. Screw the jar shut and put it in the fridge.
Standard instructions are that you can leave the water kefir for 3 weeks. But I have also heard that it works for several months.

Juices for the 2nd fermentation

In my experience, different juices produce different amounts of carbon dioxide.

Sour cherry is my favourite at the moment. Passion fruit is also great - you'll notice I like it more acidic.

Just try it out.

I've also tried it with syrup, but then leave the water kefir to stand until there's hardly any residual sweetness left. The first time I tried it, it was too sweet for me. But: it keeps for quite a long time with syrup. You can then ‘desweeten’ it with fresh water kefir, tea and juice. However, syrup does not produce carbon dioxide.

Water kefir with guayusa

Two healthy components. I prepared the kefir crystals in cooled guayusa with the same proportions as with water. Interestingly, the result is sweeter than with water (prepared at the same time), so I left it to stand for 1 day longer. It was still very sweet. But with a little lime juice and a sip of water and ice, it's a great drink.

I've chilled the rest for now and will test again tomorrow when it's less sweet.

I don't make tea with 2nd fermentation, but you can make it however you like.

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Ideas

With hibiscus, jasmine or fruit teas: test, brew the tea and use it instead of water. However, use crystals that should only live in this tea.

Alternatively, mix tea and ready-made water kefir 1:1.