Tap water Magnesium levels too high

[kalmah21]

Hello all,
Let me start by saying I am completely new to brewing water chemistry/profiles. I decided that I should look up the water report for the tap water that I have been using on all of my brews. Well, it appears that the magnesium level above the recommended range for brewing. Below is my tap water info

Calcium = 62ppm
Magnesium = 43ppm
Sodium = 2.8ppm
Chloride = 3.2 ppm
Sulfate = 6.8 ppm
Alkalinity as CaCO3 = 307

I've read that they only way to drop the magnesium level is to dilute with distilled water. According to a water calculator spreadsheet I tried, diluting 50% of total water volume with distilled water and adding 5g of Gypsum, 5g Calc. Choloride and 1 ml of Lactic Acid would give me an estimated mash pH of 5.59 and provide the following profile

Calcium = 125ppm
Magnesium = 22ppm
Sodium = 1 ppm
Chloride = 93ppm
Sulfate = 109ppm

This lists the Chloride/Sulfate ratio as 0.85 (balanced). The types of beer I brew are a wide range from light to dark. The next beer I plan to brew is an APA. Would this water profile be acceptable for a wide range of beers? Would it work for the APA I plan to brew? Any other methods to correct my water? I would like to avoid buying 7-8 gallons of distilled water each brew day to build a water profile from scratch but would consider it if my water is too difficult to correct.

 

[Yooper]

I think that it's too much. What I mean is that's both a lot of sulfate, and a lot of chloride, and calcium. For an APA, ditch the calcium chloride and you should be ok. It's not a "one size fits all" water profile at all, but for malty beers you could leave out the gypsum, and use the calcium chloride, and be just fine.

The mash pH of 5.59 leans on the high side, so I'd try to get most beers at a mash pH of 5.3-5.5. This will require more acid or some acid malt.

 

[mabrungard]

Yes, except for the Mg, that is a pretty good water. Just some acidification would neutralize the relatively high alkalinity.

That water is well suited to lime-softening, but that may not be something you want to mess with. Dilution with RO or distilled water is a decent way to knock the Mg and alkalinity down. The 50% dilution is adequate. I find that Mg in the 15 to 20 ppm range is still OK for many styles.

 

[ajdelange]

I've read that they only way to drop the magnesium level is to dilute with distilled water.

That's the easiest way but there are others. You could, for example, add calcium hydroxide to the water until the pH got up to around 10 or so. This would cause the mangnesium to precipitate as magnesium hydroxide. After decanting the water off that (and the calcium carbonate that you would also drop) you could bring the pH back down to a more reasonable level with sulfuric acid. Note that I am not recommending this because I don't think people in general should be fooling with sulfuric acid. Beyond that I haven't done the stoichimetry on this because I don't know the pH. Well, let's be honest - I'm too lazy.

 

[kalmah21]

This is what my estimated water profile would look like with 50% RO water, 5g of gypsum and 5 mL of lactic acid.

Calcium = 74 ppm
Magnesium = 22 ppm
Sodium = 1 ppm
Chloride = 2 ppm
Sulfate = 109 ppm
pH = 5.36

Does that look like an acceptable profile for an APA? I'm worried that the magnesium still looks just a bit high. Should I just drop the tap water and build off of 100% RO?

 

[mabrungard]

For an APA, that magnesium content is fine...even desirable! The sulfate level is a good starting point and I have employed similar sulfate level in my APAs, but find that its just doesn't finish dry enough and let the bittering and hop character shine. If you want to make the bittering and hops come through strongly, I suggest that 200 to 300 ppm sulfate tends to work better. There is a Pale Ale profile in Bru'n Water software that has a proven track record in brewing APAs. That can give you ideas for your water adjustments in this case.

 

[kalmah21]

Thanks to everyone for the help. I'll probably stick with the below water profile for my brew day this weekend.

50% tap water
50% RO water
5g of gypsum
5 mL of lactic acid.

Calcium = 74 ppm
Magnesium = 22 ppm
Sodium = 1 ppm
Chloride = 2 ppm
Sulfate = 109 ppm
pH = 5.36

It's gotta be better than my tap water with no adjustments right?

 

[kalmah21]

Thanks to everyone for the help. I'll probably stick with the below water profile for my brew day this weekend.

50% tap water
50% RO water
5g of gypsum
5 mL of lactic acid.

Calcium = 74 ppm
Magnesium = 22 ppm
Sodium = 1 ppm
Chloride = 2 ppm
Sulfate = 109 ppm
pH = 5.36

It's gotta be better than my tap water with no adjustments right?

I just brewed with the above water profile on Sunday and got a mash pH around 5.4 (As far as I could tell from test strips). I even was a couple gravity points higher on my pre-boil OG than usual (not sure if this is from better mash pH or some other variable).

That being said, I think I am going to use 100% distilled water on my brew. I figure I'm already buying distilled water for 50% of the water volume. I might as well just go 100% and knock out unknowns/unexpected changes in my tap water. I'm about 60 pages into the "A Brewing Water Chemistry Primer" thread and find it to be packed with great information. I plan to use the baseline profile then adjust future batches as I get a better handle on what each addition does.

Also, a pH meter is on my list.