How to filter water for fermentation

Removing chlorine and chloramine from water is an important for our health and well-being. It is also particularly important for fermentation. Here’s everything you need to know about filtering water for fermentation and clean drinking.

Water is a subject that is near and dear to my heart for the following reasons:

1. I live in an urban centre, and my city water source is treated with chloramine.
2. I started my fermentation journey to deal with a number of health issues related to poor gut health. As it turned out, filtering my drinking water played a big part in improving the health of my microbiome.

(Side note: A microbiome is the yeasts and bacteria that live in our body.)

Are you interested in learning how to filter water? Read on!

The goal of urban water treatment

No one wants to hear that their water source was contaminated with E. Coli, parasites or other nasty microorganisms. So urban water is usually filtered and treated to prevent the spread of disease.

The best way to ensure that the water is sanitized from the source right through to your kitchen tap is to add chlorine or chloramine. These chemicals are both very effective at killing bacteria and parasites.

Issues with chlorinated and chloraminated water

While it is great that our water sources are clean and safe to drink, it is not particularly good for our microbiome or fermenting. Here a few reasons why you might want to filter your water:

• Using chlorinated water for fermentation will slow or prevent the growth of lacto-bacteria and yeasts.
• You can’t use chlorinated water to fill a fish tank without potentially harming your fish.
• It’s generally better not to water your garden with chlorinated water because it is harmful for the bacteria living in the soil. (However, I admit to doing this on a regular basis.)
• If you are concerned about your microbiome, then you probably shouldn’t be drinking tap water without filtering it first.
• Washing in chlorinated water is harmful for the flora on your skin. However, all the eczema in my family resolved itself through eating a probiotic rich diet, and my kids still go to the local swimming pool once a week for lessons. So perhaps, only avoid chlorinated swimming pools if you are struggling with a very difficult skin condition.

Chlorinated water versus chloraminated water

It’s really important to know whether your water is treated with chlorine or chloramine, because it will change how you need to filter your water.

Chlorinated Water

This is probably what you think you have… however, many cities are switching to the much more stable chloramine for water treatment.

Chlorine is easy to remove:

• it will evaporate within 12 hours of sitting out on your kitchen counter
• it boils away in 20 minutes
• and it is removed by most water filters

So if you have chlorinated water then rejoice! Your off-the-shelf Brita filter is good enough.  Or better yet, simply buy yourself a few glass pitchers (affiliate links) and leave your water out on the counter overnight before drinking it.

Chloraminated Water

Chloramination is when chlorine is combined with ammonia. It is a VERY stable disinfectant.

Unfortunately, it would take 2-3 days for chloramine to dissipate at room temperature, and nearly 2 hours to boil away.  Unlike chlorine, most pass-through water filters don’t get rid of chloramine.

Don’t worry, all is not lost!  Here’s how you can dechloraminate your water:

• Throw in a few slices of lemon or orange into your water. Citric acid will break down the ammonia in an hour or two.
• Use a submerged activated charcoal filter. (See photo below.)
• There are a few other methods to remove chloramine. They mostly involve adding extra chemicals or UV light treatment. These aren’t practical for the average urbanite, so I recommend trying one of the above!