How to use calcium chloride to reduce pH level of beer wort

Tuesday, January 16, 2024
Delving into the world of brewing reveals the vital role of pH in crafting exceptional beer. 

This seemingly simple measure, which gauges the acidity or basicity of a solution on a scale from 0 (intensely acidic) to 14 (extremely basic), with 7 denoting a neutral state, is a cornerstone in the art of brewing.

The pH level in the brewing process wields considerable influence over several critical aspects: it governs enzyme efficiency, determines mineral solubility, affects the extraction of flavors from hops, and maintains yeast vitality. These factors collectively shape the final product's flavor profile, its visual appeal, and its overall quality and shelf life.

Optimal pH Range for Brewing Beer

For beer to achieve its optimal characteristics, the pH should ideally be maintained within the range of 5.0 to 5.5. 

This specific pH window is key to maximizing the efficiency of enzymes during the mashing process, crucial for the effective conversion of starches into fermentable sugars. Additionally, maintaining pH within this range promotes effective protein coagulation, which plays a significant role in minimizing haziness, thereby enhancing the beer's visual clarity.

It also establishes an environment conducive to healthy yeast fermentation, pivotal for the beer's flavor development. Straying outside this pH range can lead to undesirable outcomes, such as the emergence of off-flavors, compromised head retention, and issues with the beer's overall clarity and appearance.

Water Chemistry's Role in Brewing

Water, as the largest component in beer, has a significant impact on mash pH and, consequently, the beer's taste. Understanding and manipulating the water's mineral content enables brewers to tailor their products to specific beer styles.

Key ions in brewing water include calcium, magnesium, sulfate, chloride, sodium, and bicarbonate. Calcium is vital for lowering pH and stabilizing enzyme activity, while chloride enhances beer's fullness and sweetness.

Calcium Chloride in Brewing
Calcium chloride (CaCl2) affects water hardness and chloride content. It dissolves in water, releasing calcium (Ca2+) and chloride (Cl-) ions.
Equations and Reactions

The dissolution of calcium chloride in water is represented as:


This process releases calcium ions, which react with bicarbonate (HCO3-) in water to form calcium carbonate (CaCO3) and carbonic acid (H2CO3). The latter dissociates to release hydrogen ions (H+), lowering the pH:


Adding calcium chloride to the mash can reduce pH, enhancing enzyme activity and improving protein coagulation. It also assists in yeast flocculation and reduces beerstone formation risks.

Brewers first test water pH and hardness to determine the required amount of calcium chloride. Tools like the Brewer's Friend Water Chemistry Calculator facilitate precise measurements.

Practical Application in the Brew House

  • Measurement: Determine the exact quantity of calcium chloride based on the water report and the desired beer style.
  • Dissolving: Dissolve calcium chloride in warm water, ensuring the temperature is appropriate for efficient dissolution without degrading quality.
  • Solution Concentration: Adjust the concentration by varying the water volume used for dissolution.
  • Storage: Store unused solutions in clean, airtight containers.

Adjusting Mash pH with Calcium Chloride

  • Initial Testing: Check water pH before adding grains.
  • Adding Calcium Chloride: Integrate the solution into the mash water before adding grains.
  • Stirring: Ensure thorough mixing for even distribution.
  • Re-testing: Recheck pH after a short period and adjust as necessary.

Adjusting the Chloride to Sulfate Ratio

Different beer styles require varied chloride to sulfate ratios. This ratio significantly affects the beer's perceived bitterness and overall mouthfeel. Calcium chloride is instrumental in adjusting this balance.

Steps for Adjusting Chloride to Sulfate Ratio:

  1. Understanding the Desired Profile: Recognize the specific chloride to sulfate ratio needed for the beer style being brewed.
  2. Calcium Chloride Addition: Precisely add calcium chloride to the kettle based on the desired profile, significantly impacting taste and mouthfeel.
  3. Taste Assessment: Conduct small-scale test brews to find the right balance, using sensory evaluation to understand the effect of the chloride to sulfate ratio.

Practical Considerations

  • Incremental Adjustments: Make small, cautious additions of calcium chloride to finely tune the desired pH or chloride to sulfate ratio.
  • Consistency: Maintain batch consistency through detailed record-keeping of all adjustments.
  • Equipment Maintenance: Regular maintenance is necessary to prevent off-flavors and prolong brewing equipment life, as calcium chloride can cause residue buildup.

Monitoring and Measuring pH Levels

pH strips or digital pH meters (the latter being more accurate) are used for measuring pH in brewing.

After initial calcium chloride addition, measure pH levels. If necessary, make incremental adjustments, stirring well and re-measuring.

Troubleshooting Common Issues with pH

Mash pH issues, whether too high or low, can be corrected with further calcium chloride additions or other treatments like calcium sulfate or phosphoric acid.

For high pH, add more calcium chloride. To raise low pH, use calcium carbonate (chalk) or sodium bicarbonate (baking soda).

Safety and Handling of Calcium Chloride

  • Safety Precautions: Use gloves and eye protection when handling calcium chloride to avoid skin and eye irritation.
  • Disposal: Dilute excess calcium chloride solution with water before disposal. Check local regulations for specific guidelines.


The use of calcium chloride in brewing is a nuanced process that requires an understanding of water chemistry, precise measurements, and careful adjustments. By manipulating pH levels and the chloride to sulfate ratio, brewers can significantly influence the flavor, clarity, and overall quality of their beer. Proper handling and consistent practices ensure the production of exceptional brews.

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