Calcium chloride

Calcium chloride (CaCl₂) is one of the main brewing salts used for water mineral adjustment because both ions are commonly desired in the brewing water. Calcium improves mashing enzyme activity, beneficially lowers pH, improves protein coagulation, lowers oxalate, and improves yeast flocculation. Chloride provides a roundness, fullness, and accentuates the sweetness of the malt. Calcium chloride can be used in combination with calcium sulfate to control the sulfate:chloride ratio of the water, which affects the resulting hoppy vs malty balance of the beer.

Calcium chloride rapidly absorbs water from the air. As it absorbs more water, the amount of salt by weight decreases. Therefore, weighing on a scale is not an accurate way to measure the amount of this salt. For example, if your salt has absorbed enough water to become the hexahydrate form, it contains only half of the calcium chloride as the anhydrous form by weight! This inaccuracy can have significant negative effects on mash pH and other brewing parameters. Different commercial sources may also have different levels of purity. The best way to avoid both of these problems is to create a calcium chloride solution (dissolve the salt in water), which is stable and can be accurately measured by weight.

Products available online

Always buy food grade brewing salts.

• MoreBeer - 2 oz, 1 lb, 5 lb, 50 lb
• Pure (via Amazon) - 1 lb
• LD Carlson (via Amazon) - 1 lb

Accurately measuring the amount

As discussed above, measuring the dry salt is problematic due to the fact that it absorbs water from the air. There are a couple options to help measure the correct amount of salt.

Create a 10% solution:
A simple way to create a solution is to use 1 part calcium chloride to 9 parts water, such as 100 g salt and 900 g water to make approximately 1 liter of solution. Use cool water to dissolve calcium chloride because it will generate significant heat. Once the solution cools, measure the density with a hydrometer. The goal is to add calcium chloride until the density is 1.084, corresponding to a 10% solution by weight (at 20°C). If you overshoot the density, add more water. The solution is shelf stable when kept in a sealed container, although the density can always be checked to verify the strength. You may notice white precipitate drop to the bottom, which is the calcium carbonate impurities. 10 grams of solution contains 1 gram of calcium chloride.

Bake the salt to remove water:
An alternate option commonly suggested for increasing the accuracy of measuring your calcium chloride is to bake the salt at 392°F (200°C) for an hour or longer. The heat converts the calcium chloride dihydrate (or higher hydration) to the monohydrate or anhydrous forms, potentially removing much of the water. This works because the melting point of calcium chloride dihydrate is around 176°C, where it decomposes and releases the water. This method has several problems:

• The salt will absorb water as it is cooling, and it continues to have poor shelf stability.
• Calcium chloride monohydrate decomposes at 500°F (260°C), higher than the typical baking temperature recommended by other brewing websites.
• Heating the salt to decomposition can release toxic chlorine fumes.

Therefore, baking calcium chloride is not recommended by Brewing Forward.

Usage

To calculate how much calcium sulfate salt should be added, try our calculator for water mineral adjustment.

Using a solution: Simply weigh the necessary amount of solution with a scale and add it to the brewing water.

Using the salt directly: Add solid calcium chloride slowly while continuously mixing.

Calcium chloride should be stored in a tightly-sealed container and resealed promptly after use.

Chemical characteristics

Calcium chloride anhydrous solubility: 0.745 g/mL (at 20 °C)

See also

• Water mineral adjustment