It is time for a periodic reposting of thoughts on the water that most of us get from our taps…
The water analysis doesn’t change much from year to year from the wells that serve the Alexander Orr plant, so please don’t worry about the analysis being seven years old. If you live South of Flagler Street (and are not served by Florida City or Homestead’s municipal water supplies), this is the water that comes out of your MDWASD-supplied tap and that is likely to come out of that tap until we get (more) significant salt water intrusion into the wellfields. The only major seasonal change happens when they periodically switch from using chloramine to free chlorine as a sanitizer. I think (hope) we can all tell when that happens… 😉
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From: Scott Graham
Date: Fri, Oct 9, 2009 at 7:53 AM
Subject: Fwd: [MASH] Water Analysis for Miami-Dade (fwd)
To: Miami Area Society of Homebrewers
Following up on the Water thread, here is Martin’s very thorough analysis of water from the Alexander Orr treatment plant, which serves just about everyone in Dade County who live between Flagler Street and SW 248th Street.
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Please Note: On 10/9/13, Martin Brunard indicated that the information contained in the following email is based on a dated understanding of brewing water chemistry and portrays dated thinking. In particular, chalk is not suitable for any brewing use. Martin highly recommends that you visit the Water Knowledge page on the Bru’n Water site for up to date information. However, he acknowledged that Miami water remains a great starting point for brewing.
From: Martin Brungard
Date: Mon, May 22, 2006 at 8:52 AM
Subject: RE: [MASH] Water Analysis for Miami-Dade (fwd)
To: Scott Graham
The water report that you included was very complete. The particulars for brewing were:
Ca 21 ppm
Mg 3.4 ppm
Na 22 ppm
K 3.3 ppm
Cl 39 ppm
SO4 12 ppm
HCO3 61 ppm
Alk 50 ppm (as CaCO3)
pH 9.4 SU
I did notice that the water report did cheat a little. They reported all the alkalinity as bicarbonate (HCO3). This would not be true at the relatively elevated pH of 9.4. The bicarbonate would actually be 49 ppm and the carbonate (CO3) content would be 6 ppm. For us brewers, it doesn’t really matter. You can use the 61 ppm HCO3 value and the 50 ppm alkalinity.
Most of the water treatment in South Florida is via the Lime Softening process. I have been a consultant to many water utilities in South Florida over my years as an engineer. Lime is added to the raw water, raising the pH to at least 10.2. The calcium, magnesium, and iron are precipitated from the water and the precipitate is separated from the water. The water is then recarbonated by cascading the water over baffles to re-aerate it. Another option for recarbonating is to add potassium bicarbonate or potassium carbonate. It appears the utility is doing the later since there is slightly elevated potassium in the finished water. The recarbonation drops the pH into a more typical 8.4 to 9.2 range.
Overall, the finished water will be a very good brewing water. The water is an excellent starting point for almost every water style.
The hardness is low (but not very low) and the flavor ion content (Na, Cl, SO4) is also low.
The Residual Alkalinity (RA) is a measure of how the water will perform in a mash. The RA of the Miami water is about 33. This isn’t bad for light colored beers. It may be slightly high for the palest of beers such as pilsner. The water should probably be adjusted slightly with acid to drop the RA to about 0 for pale beers. That will require the addition of about 0.2 ml/gal (0.04 tsp/gal) of 88% lactic acid. I recommend using a graduated medicine dropper from the drug store for measuring these minute additions. I suggest that you calibrate your dropper to find out how many drops are in a ml of liquid. Then you can just say, XX drops per gallon of acid gets you to where you want the water to be.
Sparge water should always be adjusted to a pH of 5.7. With your water, it will take about 0.3 ml/gal (0.06 tsp/gal) of 88% lactic acid to drop your water into the proper range.
Anyone brewing a darker beer will need to use carbonate additions to the mash water to increase the Alkalinity and control the mash pH.
The pH will probably fall too low when mashing anything darker than about an Amber-colored beer. I suggest that sodium bicarbonate (baking soda) is a preferred addition for your water, but only a small amount. You do not want to add too much sodium to your water. You can add up to 0.5 gm/gal of baking soda and still keep your sodium content below 60 ppm. That addition will add about 90 ppm of bicarbonate (Alkalinity increases by 74 ppm as CaCO3).
The other way to increase alkalinity is to add calcium carbonate (chalk). This adds hardness and alkalinity. The net effect is that it doesn’t increase the Residual Alkalinity as effectively as the baking soda addition. But if you weren’t brewing a really dark beer, where a high RA is desired, then the chalk is a good alternative, since you can’t add a lot of baking soda.
Chalk does not dissolve well in plain water, but it will dissolve readily in an acidic mash water. The chalk treatment is for the mash only. You will not need or want to add it to the sparge water.
Adding chalk to sparge water is essentially the opposite of acidifying the sparge water. Acidifying sparge water is good, adding chalk is bad.
I hope this information is helpful to you and your MASH colleagues.