Question on Water Chemistry

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

meschaefer

Well-Known Member
Joined
Apr 21, 2009
Messages
118
Reaction score
2
Location
Astoria, NYC
I am trying to get a grasp on water chemistry and was re-reading the chapter in How to Brew on Understanding the Mash PH.

As suggested I got a copy of my local water report. I am on the Catskill/Delaware aqueduct in NYC. The report can be found here.

Looking at alkalinity the report gives the reading in mg/L of CaCO3

It is my understanding that mg/L and PPM have a 1 to 1 conversion factor...is this correct?
 
TDS 49.... Just dechlorinate and you can basically use it as if it were RO!
 
It is my understanding that mg/L and PPM have a 1 to 1 conversion factor...is this correct?

For brewing purposes, yes. (When you get to areas where the assumption that 1mL H20=1 g breaks down, it is not the same.)
 
As 1 liter of water weighs approximately 1 kg which is 1000 grams or 1,000,000 mg, one mg of something dissolved in it is 1 part per million. In the case of alkalinity, however, the meaning is somewhat different. In this case, 12.9 mg/L (the average reported alkalinity) means that the alkalinity is equivalent to the amount of alkalinity that would be found if one put 12.9 mg or calcium carbonate (limestone, chalk) into a liter of water and bubbled CO2 through it until the chalk was all dissolved and the water was at the reported pH.

An alkalinity of 100 mg/L does not mean that there are, in fact, 100 mg/L of calcium carbonate dissolved though that is one mechanism by which that level could be achieved. It does mean that there is the same amount of bicarbonate as there would be from 100 mg/L. The amount of bicarbonate ion can be calculated by dividing the reported mg/L by 50 (half the molecular weight of calcium (carbonate) and then multiplying by 61. Thus 100 mg/L alkalinity translates to about 122 mg/L bicarbonate. The actual amount is close to this but depends somewhat on the pH of the sample and the pH the analyst used as an end point when he measured the alkalinity. For alkalinity of 12.9 the approximation gives 15.7 mg/L bicarbonate. At pH 6.8 (lower end of the range in the report) the actual bicarbonate would be 15.8 (assuming titration to the "equivalence endpoint" was used in the alkalinity measurement0 though at the higher end (pH 9.2) it would be closer to 14.0. Not really at all significant at these levels.

This is a pretty impressive water system! Especially so is that they seem to be using UV for disinfection and only stabilize with chlorine for distribution (and don't use much of that). They do not say whether the chlorine is in the form of chloramine or straight chlorine. It's simple enough to determine which. Smell the water. Then let it stand overnight. If you still smell chlorine then they have used chloramine and you should add about 1/8 of a campden tablet to each 5 gallons treated. If you don't smell chlorine the next day then it was chlorine and you don't have to worry about it.

If you don't want to let it stand overnight, then you can use the campden tablet when you draw it.

This is fantastic water. You could brew Boh. Pils with it right out of the tap (or after letting it stand overnight) with no other treatment. For other more nominal beers an addition of 1 tsp calcium chloride will get the calcium up a bit and, if you want to increase the assertiveness of the hops, an equal amount of gypsum will do that (and increase the calcium as well). Try it without first, though, to see whether you like its effects or not.
 
ajdelange said:
This is a pretty impressive water system!
Just the scale of it all is pretty impressive.
The UV Facility will consist of fifty-six 40-million-gallon-per-day
UV Disinfection Units and is designed to disinfect a
maximum of 2.4 billion gallons of water per day.
The one we use at work is just a little bigger than a scuba tank. UV envy.:eek:

Man I wish I had water like that. I got sulphury, chloramine-y, hard water.:(
 
Wow- that's a new one around here. Water envy! I'm jealous.

My water is fine, except that it's HARD and alkaline. I have to buy RO water at the store, and dilute it with my tap water. I thought I was pretty lucky to not have chlorine or choramines, and here you come with the perfect brewing water. :D
 
Thanks for all the help

As I said, I was going through the book again and decided to really focus on the chapter on Mash PH. I knew I had good water, but when I was originally trying to figure out the conversion, I was making a mistake and coming up with really large, off the chart numbers. I did a little more research and found the 1 to 1 ratio and thought that might be to easy.

NYC is actually very proud of the water, taking second place this year in a contest for the country's best tasting tap water. But then again, good tasting tap water doesn't necessarily translate into good brewing water.
 
What is NYC not proud of!?!

Your water is similar to mine down in GA. The sky is your limit when it comes to beer styles with minimal water beautification.

Oh, and yes mg/L is ppm.
 
Back
Top