Scaling vs etching in boilers
Understand the difference between scaling and etching in espresso boilers and how water chemistry affects them.
- Coffee Basics Nerds
- 1 min read
Scaling vs Etching in Coffee Boilers
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Scaling:
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Formation of mineral deposits (mainly calcium and magnesium carbonates) inside boilers and pipes.
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Caused by hard water with high calcium and magnesium.
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Effects: reduced heat transfer, higher energy consumption, uneven water flow, potential clogging.
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Prevention: use softened water, regular descaling, monitor TDS and hardness.
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Etching:
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Corrosion or pitting of boiler metal surfaces, often copper or stainless steel.
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Caused by low pH, high chloride content, or aggressive water.
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Effects: metal degradation, leaks, metallic off-flavors.
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Prevention: avoid overly soft water with low buffering capacity, monitor pH, limit chlorides.
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Key Balance:
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Water must be soft enough to prevent scale but not so aggressive as to cause etching.
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SCA recommends specific hardness and alkalinity ranges to protect boilers while ensuring optimal coffee extraction.
Practical Tip: Regular water testing and adherence to recommended SCA water parameters prolong boiler life and maintain coffee quality.