I would like to know how/if chemicals such as pesticides commonly found with conventional foods or even those found in tap water; how/if they affect the quality of the kombucha first or second stage brew (continuous brewing)?

Studies have shown kombucha to have detoxifying effects on our internal organs, so at-least our organs are receiving this probiotic aid. Though I wonder does the fermentation process dismantle any chemical properties, or visa versa — can chemicals effect the quality of the fermentation process?

2 Answers 2


I would think that chemicals in your starting ingredients can affect fermentation if they contain preservatives. I imagine the right (or wrong, depending on how you look at it) kinds of preservatives will prevent fermentation (that's sort of their job, you know). Of course, since kombucha is usually just made with water, tea, sugar, and a starter culture (which should already be alive and well), you'll probably only need to worry about preservatives if you add other flavours (such as fruit juice). I'm not 100% sure which preservatives you should watch out for, but if you look for tips on making hard cider from juice, some websites will name which preservatives to stay away from. That would probably be a good place to start.

As far as tap water, I'm not sure what chemicals would interfere with fermentation. I suppose if you're worried, you could get a water filter, or buy filtered or distilled water.

Also, I'm not sure if the fermentation process will neutralize any chemicals that might be harmful to you.


Tap water's bad. Chlorine will definitely slow your initial biological processes, and increase the chances of a moldy batch. If you have pretty good tap water (or don't want to pay for bottled water), I recommend boiling it or letting it off-gas for 24 hours before using it.

I've seen people use tap water to mix-down their brew after the steep and have it ruin batches.

There are also ingredients that (conventional or organic) have an astringent effect, which slows the fermentation. Do a little research on this, it just means you should use more starter and expect a longer brew time if using these ingredients.

And no, the fermentation process won't affect any of the chemicals or whatever in conventional foods, so if you're concerned about them, don't use them.

  • Well, that depends on your water. Not all countries add chlorine to tap water. In some countries tap water is a highly scrutinized food.
    – Robert
    Commented Sep 11, 2016 at 3:11

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