Measuring Chlorine

I've been concerned for "chlorine contamination" for some time now.

I initially brewed with spring water and changed to filter tap water about the time I moved to all grain. I have been using an activated charcoal filter thinking this should do the trick. Now I'm not so sure.

This belief was based on some experiements I did several years ago while investigating the effectiveness of a whole house water filter (activated charcoal). At that time our city water supply utilized the old fashioned chlorine (sodium hyporchlorite ). I used a chlorine test kit from our pool to see the before and after results of applying the filter. The difference was obvious and rather extreme. Strong chlorine in the straight tap water. Virtually none in the filtered water.

Now comes brewing. I measured the output of my current filter using test strips purchased from my LHBS. The water looked like there was no chlorine. I then checked the water from the tap and to my surprise it looked the same??? I then added two drops of bleach to a glass of tap water and the test strip went wild with chlorine indication.

So I guess? this particular strip is only sensitive to sodium hyporchlorite (free chlorine) and not the newer chloramines used today by the water company.

So the question is... what do you guys use to measure total chlorine which picks up on chloramines as used in most urban water systems these days?

It could be that the strips only detect free chlorine. You'd have to research or call the manufacturer of the test strips to find out.

In general, chlorine test kits can measure free chlorine (hypochlorite), combined chlorine (chloramines), and total chlorine (free and combined put together). Typically, the total chlorine test is used to determine chloramines by also measuring free chlorine and subtracting the difference to get the level of combined chlorine.

Like pH testing, test strips are generally a less accurate way of measuring chlorine, but they are cost effective. If you want a cost-effective alternative, try these test strips from Hach. I've had good experiences with their products and they're a respected company in the science community. Although, I'm not sure if their products are available directly to the consumer.

I don't measure, I just crush a campden tab and stir it into my brewing water. Done.

Bobby_M said:

I don't measure, I just crush a campden tab and stir it into my brewing water. Done.

Click to expand...

X2. One campden tablet (potassium or sodium metabisulfate) will reduce the chloromines and chlorine to insignificant levels of sulfate and chloride ions in 20 gallons of water in minutes at room temperature!

I thought I'd update my own post.

Found that most chlorine test strips will not measure the presence of chloramines. Since our local water is treated these days with chloramine I consistently measured no chlorine when testing when using these strips. I had thought I was in good shape with my filtered brew water.

I found chloramine strips at a local pet supply since aquarium folks are very keen on measuring total chlorine. These strips revealed I had 2ppm in my tap water of chloramine.

I filtered some tap water using a very good activated charcoal filter which I have been using for some time now. I know from previous work that these filters are excellent at removing hypochlorite chlorines (old water treatment stuff) but I found the filter did nothing for chloramines. Before and after was the same 2ppm which also agrees with my local water report.

So, I've been dumpimg a full load of chlorine in every brew I've made for the past 8 months. I have hopes of this explaining why all my brews have a destinct off flavor problem. I have just about given up on finding the source of this until now.

I also confirmed what others are saying on the forum, that a small amount of Potassium Metabisulfite will eliminate all chlorine. I treated a sample of tap water with a few crystals of this stuff and within a couple of minutes tested the water. It was totally free of all forms of chlorine. The test strip indicated zero chlorine.

Now to make a new brew and see what comes....