# Trying to understand Bru'n Water - More minerals = lower pH??

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#### frankvw

##### Well-Known Member
I'm wanting to brew a Belgian dubbel using the water profile for Antwerp embedded in Bru'n water. I have entered the details for my local water from the lab's water report:

Calcium as Ca+ 23.25
Magnesium as Mg+ 8.75
Sodium as Na+ 17.70
Sulphate as SO42- 18.25
Chloride as Cl- 26.2
Total alkalinity as CaCO3 82.50
pH 6.86

As you can see, my water is rather soft with a fairly low pH. No bicarbonates are specified on the lab report, which is where Bru'n Water's alkalinity converter comes. It puts the bicarbonates at 100 and carbonates at 0.

I have entered my grain bill correctly:

Piilsener malt [ Base Malt] 4kg 3.3EBC
Melanoidin [ Base Malt] 750gr 51.9EBC
Biscuit [Base Malt] 450gr 50EBC
Vienna [Base Malt] 450gr 5.9EBC
Wheat [Base Malt] 350.0gr 3.9EBC
Dextrin malt [Crystal Malt] 250gr 1.4EBC
Special W [Roast Malt] 200gr 300EBC
Total batch size will be 21L.

Based on the above, Bru'n Water calculates a beer color of about 25.4EBC. Beersmith puts it at about 31. In order for Bru'n water to achieve the same beer color I need to reduce the total batch size to 15L or so. That can't be right....?

Secondly, having entered the mash and sparge water volumes as per what Beersmith suggests (16.82 and 10.6L, respectively) Bru'n Water calculates a mash pH of 5.56 based on my local water without any mineral additions.

When I then add 1 gram of gypsum and 1 gram of calcium chloride, the mash pH drops to 4.12! This makes no sense to me.

Either I've done something really stupid here (more stupid than not reading the instructions, which I have) or I'm totally misunderstanding something.

What am I missing here?

I'm wanting to brew a Belgian dubbel using the water profile for Antwerp embedded in Bru'n water. I have entered the details for my local water from the lab's water report:

Calcium as Ca+ 23.25
Magnesium as Mg+ 8.75
Sodium as Na+ 17.70
Sulphate as SO42- 18.25
Chloride as Cl- 26.2
Total alkalinity as CaCO3 82.50
pH 6.86

As you can see, my water is rather soft with a fairly low pH. No bicarbonates are specified on the lab report, which is where Bru'n Water's alkalinity converter comes. It puts the bicarbonates at 100 and carbonates at 0.

I have entered my grain bill correctly:

Piilsener malt [ Base Malt] 4kg 3.3EBC
Melanoidin [ Base Malt] 750gr 51.9EBC
Biscuit [Base Malt] 450gr 50EBC
Vienna [Base Malt] 450gr 5.9EBC
Wheat [Base Malt] 350.0gr 3.9EBC
Dextrin malt [Crystal Malt] 250gr 1.4EBC
Special W [Roast Malt] 200gr 300EBC
Total batch size will be 21L.

Based on the above, Bru'n Water calculates a beer color of about 25.4EBC. Beersmith puts it at about 31. In order for Bru'n water to achieve the same beer color I need to reduce the total batch size to 15L or so. That can't be right....?

Secondly, having entered the mash and sparge water volumes as per what Beersmith suggests (16.82 and 10.6L, respectively) Bru'n Water calculates a mash pH of 5.56 based on my local water without any mineral additions.

When I then add 1 gram of gypsum and 1 gram of calcium chloride, the mash pH drops to 4.12! This makes no sense to me.

Either I've done something really stupid here (more stupid than not reading the instructions, which I have) or I'm totally misunderstanding something.

What am I missing here?

IIRC, the entries for minerals are in g/l or g/gal. If you are entering 1 g/l for each, then you are dosing crazy amounts.

Check that and report back.

IIRC, the entries for minerals are in g/l or g/gal. If you are entering 1 g/l for each, then you are dosing crazy amounts. Check that and report back.
Bingo! That's what I did wrong. I never noticed that. Thank you, sir!

However, this still leaves me with the question of why the color calculation appears to be off in comparison with other calculators, and whymineral additions lower the calculated mash pH. Without any added minerals (i.e. using my local water, untreated) the mash pH is calculated at 5.57. Adding 0.1 g/L each of gypsum and calcium chloride (1.7 g each in total on 17L of strike water, which is not a crazy amount IMO) lowers the calculated mash pH to 5.43. Why is that? I'm adding minerals that increase the water's alkalinity, so shouldn't the mash pH go up when do that?

Gypsum and Calcium Chloride do not raise alkalinity. These two minerals calcium ions react with phosphates in the grist to liberate H+ ions into the wort, so acidity increases.

3Ca2+ + 2H3PO4 → Ca3(PO4)2 ↓ + 6H+

Last edited:
You sure you aren't comparing EBC and SRM?

Gypsum and Calcium Chloride do not raise alkalinity. These two minerals calcium ions react with phosphates in the grist to liberate H+ ions into the wort, so acidity increases.

3Ca2+ + 2H3PO4 → Ca3(PO4)2 ↓ + 6H+
Yep, it looks like @frankvw has a basic misunderstanding of how gypsum and calcium chloride affect pH.

Why is that? I'm adding minerals that increase the water's alkalinity, so shouldn't the mash pH go up when do that?

In general:

1.) Calcium salts lower pH;
2.) Magnesium salts lower pH (to a lesser degree than Calcium salts);
3.) Baking Soda and Lime raise pH by increasing alkalinity.

Gypsum and Calcium Chloride do not raise alkalinity. These two minerals calcium ions react with phosphates in the grist to liberate H+ ions into the wort, so acidity increases.

..and...

Yep, it looks like @frankvw has a basic misunderstanding of how gypsum and calcium chloride affect pH.

Indeed I did. Thank you for pointing me in the right direction! For some reason I had the idea that more minerals means more alkalinity which means less drop in pH when you mash in. Not sure how I ended up being this confused, but there you go.

Thanks for pointing me into the right direction!! It's greatly appreciated.

You sure you aren't comparing EBC and SRM?
Yes, I am sure. E.g. Pilsener malt is 3.3EBC / 1.7 SRM and since Bru'n Water uses EBC or Lovibond for grain colour, I've entered set Bru'n Water to use EBC and entered 3.3 for this grain.

.For some reason I had the idea that more minerals means more alkalinity which means less drop in pH when you mash in. Not sure how I ended up being this confused, but there you go.
Well you have half of it right where more minerals increase alkalinity. The catch is that calcium and magnesium lower pH and baking soda and slaked lime increase pH.

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