Calcium Carbonate (Chalk) 500g is an essential brewing salt used to increase residual alkalinity and raise mash pH when brewing darker beer styles. Also known simply as chalk, it is commonly added to brewing water or directly into the mash to help balance the higher acidity found in roasted and dark specialty malts.

Water chemistry plays a major role in brewing performance and flavour development. Dark beers such as Stouts, Porters, Brown Ales, and other malt-forward styles often require higher carbonate levels to prevent the mash from becoming overly acidic. Calcium Carbonate (Chalk) 500g provides the carbonate ions needed to increase alkalinity and help maintain optimal mash conditions.

The carbonate component helps buffer acidity during mashing, while the calcium contributes several important brewing benefits. Calcium supports enzyme activity, improves yeast performance, assists with protein precipitation during the boil, and contributes to overall beer stability and clarity.

Unlike brewing salts such as gypsum or calcium chloride, which are often used to lower mash pH, Calcium Carbonate (Chalk) 500g is primarily used when brewers need to increase alkalinity and raise mash pH. This makes it particularly useful when working with very soft water or brewing recipes that contain large percentages of dark roasted grains.

Whether you’re building a custom water profile, recreating traditional brewing water from historic beer regions, or simply adjusting your local water supply, Calcium Carbonate (Chalk) 500g is an important tool for producing balanced dark beers with improved mash performance.

Key Features

• Raises residual alkalinity
• Increases mash pH
• Adds calcium and carbonate ions
• Ideal for dark beer styles
• Helps balance acidic dark malts
• Supports healthy yeast performance
• Improves brewing water chemistry
• Can be added to brewing water or mash
• Useful for custom water profile adjustments
• Suitable for all-grain brewing

Benefits for Brewers

Raises Mash pH

• Helps counter acidic dark malts
• Supports optimal mash conditions
• Improves brewing consistency

Increases Alkalinity

• Boosts residual alkalinity
• Improves buffering capacity
• Supports darker beer recipes

Supports Brewing Performance

• Provides beneficial calcium
• Supports enzyme activity
• Assists yeast health and beer stability

Ideal Beer Styles

• Stout
• Imperial Stout
• Porter
• Brown Ale
• Robust Porter
• Dark Mild
• Schwarzbier
• Dark Belgian Ales

Water Chemistry Information

Calcium (Ca)

Calcium is one of the most important brewing minerals and contributes to:

• Improved mash performance
• Enhanced yeast health
• Better protein precipitation during the boil
• Increased beer stability
• Improved clarity

Preferred calcium levels for brewing:

• 50–150mg/L

Carbonate & Bicarbonate (CO₃ / HCO₃)

Carbonate is one of the most important ions for controlling mash acidity.

Recommended levels:

• 25–50mg/L for pale beers
• 100–300mg/L for darker beers

Higher carbonate levels help offset the acidity contributed by roasted and dark malts.

Ion Contribution

1 gram of Calcium Carbonate per litre of water contributes approximately:

• 400ppm Calcium (Ca²⁺)
• 600ppm Total Alkalinity as CaCO₃
• 20 mEq/L Alkalinity as CO₃²⁻

Adjusting Brewing Water

Different beer styles require different water profiles. Brewers commonly use water treatment salts to modify their local water supply and match target brewing profiles.

Common brewing salts include:

• Calcium Carbonate (Chalk)
• Calcium Sulphate (Gypsum)
• Calcium Chloride
• Magnesium Sulphate (Epsom Salt)
• Baking Soda
• Table Salt

For best results, use a brewing water calculator or water profile software to determine accurate addition rates for your specific brewing water and recipe.

Product Information

Product Type:
Brewing Water Treatment

Also Known As:
Chalk

Weight:
500g

Primary Ions Added:
Calcium (Ca²⁺) and Carbonate (CO₃²⁻)

Suitable For:
Dark Beers, Water Chemistry Adjustment, Mash pH Control, All-Grain Brewing