The question I will address this week is one related to water and how to convert the water we have to the water we want. Let’s assume we want to brew our sake with water that is equivalent to Miyamizu, the heavenly water from Nada. For this example the water we will start with is from the Bull Run Reservoir.
You may recall from “Miyamizu – Heavenly Water – The Gold Standard?” that the mineral content of the miyamizu water is:
And that the mineral content of the Bull Run reservoir is:
|Bull Run water (ppm)|
Where should we start? Well, from the tables above we can see that we need to increase the potassium from 0.2ppm to 20ppm or by 19.8ppm. That is close enough to 20ppm that we can just use 20.
Ions are usually measured in parts per million (ppm). But we need to know how many grams of potassium chloride to add. Well, parts per million is equivalent to milligrams per liter, mg/L, and this is just what we need.
If we want to provide the correct concentration for the moto, we will need to hit 20ppm in 2.5 cups of water. 1 cup is 0.24 liters, so 2.5 cups is 0.6L.
0.6L * 20mg/L = 12mg of potassium
Now, only 52% of potassium chloride (KCl) is potassium (see table below). So we will need:
12mg/0.52 = 23mg of KCl
Now we can do the same for magnesium using the salt magnesium sulfate (MgSO4). We want the water to have 5.6ppm of magnesium but it only has 0.9ppm. So, we need to increase magnesium by 4.5ppm.
0.6L * 4.5mg/L = 2.7mg of magnesium
Now, again from the table we see that only 10% of the salt is magnesium, so
2.7mg/0.1 = 27mg of magnesium sulfate
We could do the same for calcium and sodium. However, with each of these salts we are adding other ions that we are not specifically interested in adding. For example, we would be adding chloride and sulfate with the above two additions. Often this is not an issue but we should not ignore them because they could reach concentrations that could have negative effects.
|Common Name||Name||Chemistry||Weight g/mol||Ions|
|Gypsum||Calcium Sulfate||CaSO4*2(H2O)||172||Ca = 23%||SO4 = 56%|
|Calcium Chloride||CaCl2*2(H2O)||146||Ca = 27%||Cl = 48%|
|Potassium Chloride||KCl||75||K = 52%||Cl = 48%|
|Epsom salts||Magnesium Sulfate||MgSO4*7(H2O)||246||Mg = 10%||SO4 = 39%|
|Chalk||Calcium Carbonate||CaCO3||100||Ca = 40%||CO3 = 60%|
|Table salt||Sodium Chloride||NaCL||58||Na = 40%||Cl = 60%|
More on water to come.