Best way to dechloraminate tap water?
June 23, 2011 12:43 PM   Subscribe

What's the best way to remove chloramine from tap water for the purpose of soaking grains?

I'm interested in experimenting with soaking and fermenting grains to reduce the phytic acid (as suggested here and here on the Whole Health Source blog, among other places).

According to that guy, soaking and fermenting don't work properly when there's chlorine or chloramine in the water.

Here in San Francisco, they put chloramine in the tap water.

I don't mind drinking or cooking with chloraminated water, but if it will interfere with the soaking and fermenting, I'll need to do something about it.

Leaving it out overnight would work with chlorine, but not chloramine.

I've seen a variety of suggestions, including adding vitamin C to the water or using chemicals from pet stores.

What would be the most effective, easiest, cheapest way to dechloraminate my tap water?

And is there any easy way to test the water to make sure I've gotten the chloramine out?

Very specific specifics (like "use 500mg of vitamin C; it's okay to cut a vitamin pill in half") would be great.

I'd especially appreciate answers from anyone who's actually doing this - removing chloramine in order to soak grains (or legumes).

posted by kristi to Food & Drink (17 answers total) 4 users marked this as a favorite
I don't know if it is the best way, but Brita water filters would remove most of the chlorine compounds.
posted by Blazecock Pileon at 1:08 PM on June 23, 2011

Best answer: go buy the cheapest gallon jug of distilled water at your grocery store. Use it.


That's what I do for my sourdough, since the chlorine in tap water can impair growth of the yeast/bacteria that make sourdough good.
posted by k5.user at 1:09 PM on June 23, 2011

Homebrewers use Campden tablets (potassium metabisulfite) to remove chloramine from brewing water. You should be able to buy them at any local or online homebrew store. The recommended amount for simple dechlorination, though, is one tablet for 20 gallons of water, so that might not be practical.
posted by uncleozzy at 1:13 PM on June 23, 2011

Best answer: Bamboo charcoal. Cheap, safe, easy, compostable. In SF, you can buy sticks at Soko Hardware in Japantown.
posted by judith at 1:26 PM on June 23, 2011 [1 favorite]

Response by poster: Just to clarify - as I understand it, chloramine interacts with water (and removal processes) differently from chlorine, so please be sure you're talking about chloramine removal, not regular chlorine. For example, I've seen several sites saying that Brita filters don't affect chloramine, although it's hard to find anything definitive.

posted by kristi at 1:39 PM on June 23, 2011

For brewing I use an aquarium inline filters. It does a fantastic job from the tests I have done.
posted by Felex at 2:13 PM on June 23, 2011

Best answer: The San Francisco Public Utilities Commission says one 1000 mg tablet of vitamin C will work on a bathub of water, about 40 gallons. I would crush the portion of the tablet that you use. I am not your biochemist, but I would be surprised if a slight excess of vitamin C would inhibit the phytase activity that you seek.

The half time of the reaction between ascorbic acid and chloramine is 4 minutes, so if you let the vitamin C react for an hour you should be in good shape.
posted by exogenous at 2:18 PM on June 23, 2011 [4 favorites]

If you look at the link for bamboo charcoal above, you'll see that it is specifically recommended for chloramine. It is my understanding that Brita filters are ineffective for this.
posted by judith at 2:28 PM on June 23, 2011

Minor data point: my water has chloramines in it, to the extent that yeast wouldn't rise. Running it through two Brita pitchers in series rendered it able to rise dough. Was it gone? Probably not. But it was gone enough for the yeast.
posted by gjc at 3:39 PM on June 23, 2011

Best answer: You can boil water for 20 minutes to remove chloramine. Brewers don't do this because it can taste strange, but it won't matter for your purposes.

It is my understanding that Brita filters are ineffective for this.

Actually, the activated carbon in a Brita would work just fine for removing (adsorbing/catalyzing) chloramine if it were in contact with the water long enough; the ion exchange resins would remove the catalytic byproducts, something that charcoal alone doesn't do, IIRC. However you'd need the Brita filter to just sit in the water for ten minutes, instead of having the water run through (or run through much more slowly).

Activated charcoal is going to be more effective in smaller amounts than non-activated, due to more surface area. Bamboo charcoal can be activated or not, depends on if it has gone through the activation process.
posted by oneirodynia at 3:53 PM on June 23, 2011

We have a replaceable cartridge water filter under the kitchen sink that works like a Brita but you don't have to wait. It's piped to a separate faucet but can also just put it in the cold water line to your regular faucet. I use the filtered water for most of my cooking.
posted by tommasz at 3:53 PM on June 23, 2011

Use Aquarium water conditioner, a little goes a long way.
posted by joannemullen at 5:44 PM on June 23, 2011

Reverse-osmosis filters get enough of everything out that what's still in is not worth worrying about.
posted by flabdablet at 6:13 PM on June 23, 2011

Aquarium water conditioners will remove chloramines, but they will leave behind other substances (sulfates, etc.) that you may not want in water you're going to use for food prep.

RO/DI filters will work, but they're a fairly expensive solution, and need specifically designed cartridges to reliably remove chloramines. This is going to be a $150+ solution.

Unless you really need a lot of water on an ongoing basis, buying distilled or commercially filtered water in 1 to 5 gallon jugs may be your most cost-effective solution.
posted by nonliteral at 6:51 PM on June 23, 2011

Best answer: Thank you for asking this question.

I have been naively assuming boiling my water would be as effective for removing chloramine as for getting rid of traditional chlorine.

The 12th reference of the Wikipedia article on chloramine links to a PDF ("Experiments in Removing Chlorine and Chloramine From Brewing Water") which discusses methods of removing chloramine from water with a view toward brewing.

The author is maddeningly discursive and poor at summarizing, but he does finally get around to providing much useful information based on his own careful-sounding experiments. For example, he found that a single pass through a Brita left 16% of the chloramine behind, implying that two passes would get rid of more than 97%, and he claims that boiling for 26 minutes is necessary to remove half of the chloramine.
posted by jamjam at 12:10 AM on June 24, 2011

Best answer: Hmm, the information I have on removing chloramine from water by boiling for 20 minutes is from the SFPUC. I wonder if they use much less NH2Cl than other districts; Hetch Hetchy is one of the cleanest municipal water sources in the US. Here's what they say:

However, chloramine is very easily and almost instantaneously removed by preparing a cup of tea or coffee, preparing food (e.g., making a soup with a chicken stock). Adding fruit to a water pitcher (e.g., slicing peeled orange into a 1-gal water pitcher) will neutralize chloramine within 30 minutes. If desired, chloramine and ammonia can be completely removed from the water by boiling; however, it will take 20 minutes of gentle boil to do that. Just a short boil of water to prepare tea or coffee removed about 30% of chloramine. Conversely, chlorine was not as consistently removed by boiling in SFPUC tests. If desired, both chlorine and chloramine can be removed for drinking water purposes by an activated carbon filter point of use device that can be installed on a kitchen faucet. If desired, both chlorine and chloramine can be removed for bathing purposes by dissolving Vitamin C in the bath water (1000 mg Vitamin C tablet will neutralize chloramine in an average bathtub). SFPUC does not recommend that customers remove disinfectants from drinking water. Customers desiring to do so should consult with their physician.
posted by oneirodynia at 9:40 AM on June 24, 2011

Response by poster: Great answers, everyone - thank you so much!

If I get around to it, I'll update the thread and post my own results. I'm thinking of trying sliced citrus or vitamin C tablets first off - and I might just stop in at Soko Hardware for some bamboo charcoal as well.

posted by kristi at 10:58 AM on June 24, 2011

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