Calcium Carbonate Powder (Chalk) – 2 oz or 1 lb | Brewing Water Adjustment

Raise Mash pH and Add Carbonate for Dark Beer Water Profiles

Calcium Carbonate (chalk) is a classic brewing water adjustment used to increase alkalinity and help prevent mash pH from dropping too low—especially in dark, roasted-grain beers. It can be useful when building traditional water profiles for styles like stout, porter, and other malt-forward dark ales where added alkalinity helps balance acidity from roasted malts.

At SoCal Brewing Supply, we carry Calcium Carbonate in powder form in both 2 oz and 1 lb sizes, making it easy to stock a small jar for occasional use or keep a bulk bag on hand for frequent water building.

Key Characteristics

• Product: Calcium Carbonate (CaCO₃)
• Form: Powder
• Use: Raises alkalinity and helps support higher mash pH in acidic/dark grists
• Best For: Dark beers and water profiles that need added carbonate
• Sizes Available: 2 oz and 1 lb

When to Use Calcium Carbonate

• Dark Grain Bills: Roasted barley, black malt, chocolate malt, and other acidic malts can push mash pH low
• Low-Alkalinity Water: Soft water sometimes needs extra buffering to keep mash pH in range
• Classic Profiles: Helpful for building stout/porter-friendly water with higher carbonate

How to Use

• Use a Water Calculator: Add chalk based on predicted mash pH and target alkalinity
• Best Practice: Calcium carbonate does not dissolve well in water, so it’s typically added directly to the mash
• Go Slow: Small additions can make a meaningful difference—measure carefully and re-check pH if possible
• Target Mash pH: Many brewers aim for roughly 5.2 - 5.6 at mash temperature, depending on style and preference

Storage & Handling

• Keep Dry: Store sealed and away from humidity to prevent clumping
• Easy Measuring: Powder form is simple to weigh for precise water adjustments