Help with Boston Water Report (chlorine levels)

So I am getting a plastic off-taste in my IPA that I kegged two weeks ago, and I am trying to pinpoint whether it could be my water or keg, tubing, infection, etc.

Anyway, I had a question on chlorine levels in the Boston water report, found here:

http://www.mwra.state.ma.us/monthly/wqupdate/pdf/2012-cy-data/092012.pdf

The 3rd to last page page says Minimum Residual Chlorine for Boston is 0.25 ppm, but the Average Residual Chlorine is 1.85 ppm, which I though was extremely high as I had the understanding that anything over 0.5 ppm was high.

Also, on the water quality page (last page), it doesn't show any values for Chlorine under the Wachusett system (which feeds Boston), except for "Chlorine, Total" of 2.9 ppm (which is also high?).

However, I was reading another post, here, that said MWRA doesn't use chlorine, they use ozone and chloramines as disinfectants, so there shouldn't be any chlorine in the water.

Anyway, long story short, does Boston have high chlorine levels? I am guessing no since I know the Sam Adams brewery in Boston uses city water and they claim not to treat it at all. But on the other hand, the report above seems to say yes.

Any help would be appreciated!

:fro:

Public water systems in the US are required by law to have a disinfectant residual throughout the piping system. The 1.85 ppm residual chlorine is not high by any measure. Exceeding 3 ppm in the piping system is fairly rare, but not illegal. The water company can super-chlorinate their water at any time to ensure the sanitation of the lines.

Since chloramine is used in Beantown, the 'total chlorine' value is what is pertinent. The other value a water user may see is 'free chlorine'. Free chlorine is not bound to other molecules. Total chlorine is bound to a molecule and is typically an 'amine' molecule that was created by reaction with ammonia.

If you are not performing active measures to remove chlorine or chloramine from the brewing water, its likely that the off taste is the result of chlorophenol production via the chlorine compounds. In the case of chloramine, using a metabisulfite compound is probably the easiest treatment method. Another option is to use an activated carbon filter. But if the typical 10" filter canister is used, the flow rate through the filter has to be reduced to a ridiculously low rate in the 0.1 gallon per minute range. Since most brewers are a little too impatient for that, the metabisulfite (Campden tablet) treatment is easier.

Read more about this on the Water Knowledge page of the Bru'n Water website.

This has been posted here a million times but one more can't hurt. Get a Campden tablet. Put it in a glass and crush it with a spoon. Add some warm water and stir. It will be hard to get it all to dissolve but it doesn't have to. Put the water to be treated in a pot, kettle or what have you. Add bits of the liquid from the glass a little at a time and stir. Then agitate the treated water and sniff. If you still smell chlorine add a bit more of the liquid. Keep doing that until you don't smell chlorine any more. If you smell a bit of sulfur dioxide, that's fine and confirms you have gotten all the chlorine - free and chloramine. If you conclude that you smell sulfur dioxide be sure it is coming from the water - not your hands or the glass with the Campden tablet in it. The latter will smell strongly of sulfur dioxide (metabite is often referred to as 'solid sulfur dioxide'). You should need half or less of a Campden tablet to treat 10 gallons of water. If you find you are needing more you are probably doing something wrong as 1 typical tablet will treat 20 gal of water chloraminated (no free chlorine - this is the worst case) to 3 mg/L free chlorine equivalent.

If you even suspect chloramine (and if you live in even a medium sized city you should) a Campden tablet is awfully cheap insurance.

Hmmm, Campden tablet it is then. It's odd though, this is the first time I've had this flavor out of 10 or so beers I've done in Boston... and I didn't taste any hint of this plasticy/rubbery flavor pre-kegging. I was also thinking it had something to do with my hoses or keg, or too much star san, or some residue from the caustic soda I used to clean it. But I just wanted to check the water/chlorine theory as well.

But I'll try the campden tablet next time. Is there any harm in using it? Like if use 1 tablet and there's not enough chlorine for it to react to, would the extra campden (or metabisulfate?) cause other off flavors?

I find that many new brewers do not recognize chlorophenol until its hitting them over the head or its pointed out by an experienced taster. Once those brewers recognize it, they tend to notice it more frequently.

Beers with more delicate/subtle flavors are more likely to show flaws, including chlorphenolics and there seems to be quite a bit of variability in how much chlorphenolic flavor a given level of chloramine can produce. Beyond this the relative amounts of chlorine and chloramine and the total amount of chlorine (i.e. the amount in both forms) often is adjusted by the utility. For example, in our nations capitol, they goose the level in the spring (there are still some wooden mains in existance). Maybe that explains some of the insanity there but that doesn't seem to be seasonal.

People always ask about byproducts and extra bisulfilte. The byproducts of treatment are sulfate ion, ammonium ion and chloride ion and the amounts produced are very small for typical chlormaine levels. The ammonium may arch an eyebrow but it is actually beneficial to yeast which use it as a nitrogen source. Un reacted metabite converts to sulfur dioxide which either reduces something (good) in the process being converted to sulfate or flies off when the water/mash is heated.

I've been through the Sam Adams tour an they said that they is the boston public water without any filter. They also said that they replicate their water in their other breweries in PA to taste the same as Boston's water.