Food-Grade Magnesium Sulphate for Brewing Water
Adjust the magnesium and sulphate content of your brewing water with food-grade Magnesium Sulphate, commonly known as Epsom salt.
Magnesium supports healthy yeast activity, while sulphate can help produce a drier finish and enhance the perception of hop bitterness. It is particularly useful when building a brewing water profile from reverse osmosis or other low-mineral water.
This 250g packet is intended for precise brewing water adjustments and should be measured according to your water profile and recipe requirements.
Why You'll Love It
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Food-grade magnesium sulphate
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Adds magnesium and sulphate ions to brewing water
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Supports healthy yeast activity
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Can enhance dryness and hop bitterness
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Useful for pale ales, IPAs and other hop-forward beers
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Suitable for adjusting reverse osmosis water
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Does not add calcium or chloride
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Convenient 250g resealable packet
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Suitable for use with brewing water calculators
What Does Magnesium Sulphate Do in Brewing?
Magnesium sulphate supplies two important brewing water ions:
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Magnesium: A yeast nutrient and enzyme cofactor that supports fermentation at appropriate concentrations
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Sulphate: Accentuates hop bitterness and can produce a drier, crisper finish
It can also reduce mash pH slightly, although its effect is considerably smaller than calcium-based brewing salts or brewing acids.
When Should Magnesium Sulphate Be Used?
Magnesium sulphate is most useful when your brewing water requires additional magnesium and sulphate without adding more calcium.
It may be suitable for:
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Pale ales
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India pale ales
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West Coast IPAs
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Extra pale ales
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Dry and hop-forward beers
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Reverse osmosis water profiles
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Low-mineral brewing water
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Recipes requiring additional sulphate without calcium
It should only be added after considering the existing mineral content of your water and the requirements of the beer being brewed.
How to Use
Use an accurate scale to measure the amount specified by your recipe or brewing water calculator.
Magnesium sulphate can be mixed through the crushed grain before mashing or added according to your chosen brewing water treatment method.
For the most accurate results:
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Obtain or estimate your starting water profile.
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Enter the profile into brewing software such as Brewfather.
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Select the target water profile for your beer.
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Add only the calculated quantity of magnesium sulphate.
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Check the predicted magnesium and sulphate concentrations before brewing.
Do not use a fixed amount for every batch, as the correct addition depends on your starting water, batch size and target beer style.
Approximate Mineral Contribution
Food-grade Epsom salt is generally magnesium sulphate heptahydrate.
As an approximate guide, 1g added to 23 litres contributes around:
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4.3ppm magnesium
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17ppm sulphate
These figures are approximate and should be confirmed using your brewing water calculator and the exact product specification where required.
How Much Should I Add?
There is no universal dosage because every water supply and beer recipe is different.
Malted grain already supplies magnesium, so many beers require little or no additional magnesium sulphate. Excessive additions may produce an unpleasant bitter or sour mineral character.
Always calculate the addition from your starting water profile rather than adding Epsom salt automatically.
Is Magnesium Sulphate the Same as Epsom Salt?
Yes. Magnesium sulphate is commonly called Epsom salt.
For brewing, use a food-grade product without fragrances, perfumes or bath additives. This product is food grade and suitable for brewing water adjustments.
Is Magnesium Sulphate a Substitute for Calcium Sulphate?
No. Magnesium sulphate and calcium sulphate both add sulphate, but they supply different minerals.
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Magnesium sulphate adds magnesium and sulphate
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Calcium sulphate adds calcium and sulphate
Calcium sulphate is generally used when the water requires additional calcium, while magnesium sulphate is useful when magnesium is required without increasing calcium.
Will It Lower Mash pH?
Magnesium sulphate may lower mash pH slightly, but it should not be relied upon as the main method of controlling mash pH.
Calcium salts, acidulated malt, phosphoric acid or lactic acid may provide more effective pH adjustment depending on the recipe and starting water.
Can Too Much Magnesium Sulphate Affect Beer Flavour?
Yes. Excessive magnesium may create an unpleasant sour, bitter or mineral flavour.
Use a brewing water calculator and measure carefully. More magnesium sulphate does not automatically produce better fermentation or stronger hop character.
Is It Suitable for Reverse Osmosis Water?
Yes. Magnesium sulphate can be useful when rebuilding a water profile from reverse osmosis water because it allows magnesium and sulphate to be added in a controlled amount.
It will normally be used alongside other brewing salts selected for the target beer style.
Storage
Keep the packet tightly sealed and store it in a cool, dry location away from moisture.
Magnesium sulphate can absorb moisture from the air, which may cause clumping and reduce measuring accuracy.
Why Buy from Border Brewing Supplies?
Border Brewing Supplies stocks brewing salts, acids and water-treatment products for home brewers throughout Tweed Heads, the Gold Coast, Northern Rivers, Brisbane and the wider Queensland–New South Wales border region.
Shop online for Australia-wide delivery or select Click & Collect from our Tweed Heads South home brew shop.
Recommended Products
For accurate brewing water adjustment, consider adding:
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Calcium sulphate
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Calcium chloride
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Sodium chloride
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Phosphoric acid
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Lactic acid
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Digital brewing scales
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Digital pH meter
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Mash pH test strips
