We cannot stress this enough… your water must be pure! For cheese, kombucha, water kefir, veggies, sourdough…obtain good quality water.
You are feeding living organisms, and those bacteria and yeasts are crucial to the fermentation process. Chemical additives like chlorine, chloramine and fluoride will harm your cultures.
The best water in my opinion is one filtered with a good quality filtration system that takes out the bad stuff (chlorine, chloramine, fluoride) but leaves in the good stuff (i.e. minerals). Stay away from the cheaper filtration systems like a Brita or your fridge filter…the additive list is not extensive as to what they filter. Be sure to research and find the list of chemicals and additives that that particular filter will remove. Try out Water Filter Labs to start your research. Yep, Brita is on there, and it ranks as the worst performing. Note: Even though fridge filters usually take out chlorine, they rarely take out fluoride or chloramine.
My personal favorite the last 8-9 years? The Berkey Water Filter system. And, if you have fluoride in your water (likely it’s there), they carry separate fluoride filters. It’s well worth the investment.
Bottled water is a toss up. Plain spring water is perfect, but not one that boasts about higher or added mineral content, or is “sparkling”. Water labeled as “drinking” is usually great – but always read the ingredient label in case they’ve added something. Don’t get the fancy and expensive water that’s alkalinized, sparkling, ozonated, extra mineralized or whatever marketing terms the water companies throw in to get you to spend more money. Just say no thank you and walk on by.
Water softeners tend to be problematic as well. Why? Not sure, but generally when folks have issues, and troubleshooting uncovers nothing, it turns out the water went through a softener. I’ve heard for example though that the potassium is too high in soft water for beer/yeast, so it makes sense to me that cultures would also fail.
Boiling water is not a win win – even though you may be able to boil out chlorine, you cannot boil out chloramine or fluoride, let alone other additives.
Distilled water is an option to get rid of contaminants or excess minerals, but doing so at home may not be optimal. Purchase it from the store, and consider adding back in trace minerals, especially for water kefir.
If all of this is overwhelming, the easiest option is bottled spring water. Nothing fancy, no extra anything, no bull for your bacteria, ok?
Now go, Go Get Fermented!