Is it safe to use copper measuring cups?

December 5, 2025 •

4 min read

According to the National Institutes of Health, copper is an essential trace mineral needed by the human body in small amounts for critical functions. However, the safety of using copper kitchenware, such as measuring cups, depends entirely on its construction and the type of ingredients it contacts. Pure, unlined copper can be reactive and pose risks, while modern, lined versions are generally considered safe for kitchen use.

Quick Summary

The safety of copper measuring cups relies on whether they are lined or unlined. Lined cups, typically with stainless steel or tin, are safe for use with both acidic and non-acidic ingredients. Unlined copper can react with acidic substances, potentially leaching unsafe levels of copper and causing toxicity over time. Proper care and maintenance are also crucial for ensuring longevity and preventing corrosion.

Key Points

Lined is Safe: Choose copper measuring cups with a food-safe interior lining, like stainless steel, to prevent copper leaching into food.
Avoid Acidic Contact: Never use unlined copper with acidic ingredients such as vinegar, lemon juice, or tomato products to prevent a toxic chemical reaction.
Hand Wash Only: Always hand wash copper measuring cups with mild soap and warm water, avoiding the dishwasher, which can damage the finish and lining.
Dry Thoroughly: Immediately and completely dry copper measuring cups after washing to prevent tarnishing and water spots from forming.
Aesthetic and Durable: Properly cared-for, lined copper measuring cups offer both a beautiful aesthetic and durable construction for long-term use.
Limited Unlined Use: Unlined copper is best reserved for specific, non-reactive tasks like whisking egg whites, where the copper aids in creating more stable foams.

The Truth About Copper's Reactivity

Copper's primary safety concern stems from its reactivity with acidic foods and liquids, such as vinegar, lemon juice, wine, and tomato products. When acidic substances come into contact with bare, unlined copper, a chemical reaction can occur. This reaction can cause copper salts to leach into the food, which can be toxic if ingested in large quantities. Symptoms of copper toxicity can include nausea, vomiting, diarrhea, and abdominal pain.

For this reason, reputable modern manufacturers line their copper cookware and measuring cups with a non-reactive metal, typically stainless steel or tin. This food-safe lining acts as a protective barrier, preventing the copper from coming into direct contact with ingredients and eliminating the risk of copper leaching.

Lined vs. Unlined: The Crucial Distinction

Not all copper measuring cups are created equal. The key factor is whether the interior surface is bare copper or protected by a food-grade lining.

Benefits of Lined Copper Measuring Cups

Safe for all ingredients: The protective barrier allows for safe measurement of all types of ingredients, including highly acidic ones.
Durable: Stainless steel-lined copper cups are highly durable and resistant to scratches and corrosion.
Aesthetic appeal: They still provide the classic, elegant look of copper on the exterior.
Hygienic: Copper has natural antimicrobial properties, which, combined with the non-reactive lining, makes them a hygienic choice.

Risks of Unlined Copper Measuring Cups

Chemical reaction: Acidic foods can react with the copper, potentially contaminating ingredients.
Metallic taste: Leaching copper can impart an unpleasant metallic taste to food and liquids.
High maintenance: Unlined copper requires more careful, delicate cleaning to prevent tarnish and corrosion, and is not dishwasher safe.
Limited use: They can only be safely used with non-acidic or dry ingredients.

How to Care for Copper Measuring Cups

Proper maintenance is essential to ensure the safety and longevity of your copper measuring cups, especially those that are lined.

Hand wash only: Never place copper measuring cups in the dishwasher, as the harsh detergents and high temperatures can damage the finish and potentially compromise the interior lining.
Clean immediately: Wash the cups with warm, soapy water and a soft sponge immediately after each use.
Dry thoroughly: After washing, dry the cups completely with a soft cloth to prevent water spots and tarnish.
Regular polishing: For a shiny finish, polish the exterior occasionally with a copper-specific cleaner or a homemade paste of lemon and salt.

Comparison Table: Copper vs. Other Materials


Feature	Lined Copper	Stainless Steel	Glass	Plastic
Safety (Acidic Foods)	Safe	Safe	Safe	Safe (BPA-free)
Durability	High	Very High	Medium (breakable)	Low (can crack)
Aesthetic Appeal	High	Medium	Medium	Low
Dishwasher Safe?	No	Yes (usually)	Yes	Yes (usually)
Liquid Measurements	Good	Good	Excellent (with spouts)	Good (with spouts)
Dry Measurements	Excellent	Excellent	Poor (can cause parallax error)	Fair (lightweight)
Heat Reactive?	No (due to lining)	No	No	Yes (melts/warps)
Tarnishes/Patina	Yes (exterior)	No	No	No

Identifying Quality and Safety

When purchasing copper measuring cups, prioritize safety by checking the product description and customer reviews to ensure the set is properly lined. Look for clear indications that the interior is made of a food-safe metal, such as stainless steel. This is more critical than a thick exterior copper coating, as the barrier prevents any reaction with your ingredients.

For those interested in the historical and practical uses of unlined copper, it is traditionally used for non-reactive purposes. For example, unlined copper bowls are excellent for whisking egg whites because the copper ions form stable bonds with the egg proteins, resulting in a more voluminous and stable foam. However, for general cooking and measuring tasks, especially with liquids, lined measuring cups are the safe and practical choice.

Conclusion

Using copper measuring cups is perfectly safe, provided you choose products that are lined with a non-reactive, food-grade material like stainless steel. The risk of copper toxicity only arises when acidic foods come into contact with unlined copper surfaces, which is not an issue with modern, properly constructed sets. By selecting a lined set and following proper hand-washing and drying procedures, you can enjoy the classic elegance and durability of copper in your kitchen without any health concerns.

Health Note

While copper is a necessary nutrient, and exposure from lined cookware is minimal, those with certain rare genetic conditions, such as Wilson's disease, which causes the body to retain excess copper, should consult a doctor regarding any copper exposure. For the general population, the trace amounts from incidental contact with tarnished exterior surfaces are not a cause for concern.

Sources

National Institutes of Health Centers for Disease Control and Prevention | CDC Advanced Mixology

Frequently Asked Questions

No, copper cookware is not inherently toxic. The danger lies in unlined copper reacting with acidic foods and leaching copper salts. Modern, quality copper cookware is lined with a non-reactive metal, making it safe for all food types.

Using an unlined copper cup with an acidic ingredient can cause a chemical reaction where copper leaches into the food. This can cause the food to develop a metallic taste and, in larger doses, can lead to copper poisoning with symptoms like nausea and abdominal pain.

Most modern, reputable copper measuring cups are lined. The interior will have a different appearance and sheen than the exterior, often a silvery color if lined with stainless steel or tin. Always check the manufacturer's product details.

Yes, lined copper measuring cups are suitable for measuring both wet and dry ingredients. For dry ingredients, ensure they are leveled off correctly, and for wet, make sure they are promptly cleaned.

Dishwasher detergents and high heat can be highly corrosive to copper, stripping its finish and damaging any interior lining. This accelerates tarnishing and reduces the lifespan of the cups.

Beyond their aesthetic appeal, copper measuring cups are exceptionally durable. High-quality ones are resistant to breaking or bending, and they offer antimicrobial properties. For cooking applications, copper is an excellent heat conductor.

Yes, unlined copper bowls are famously used for beating egg whites. The copper ions react with the egg proteins, creating more stable and voluminous foam. For this specific purpose, unlined copper is safe and effective.