Copper, the pinkish-orange brassy metal that coats our pennies can also be found in the kitchen! We often see copper in those fancy mugs known for serving Moscow mules, but it is also found in other kitchenware like pots and pans. You may have seen some articles or blog posts warning about the dangers of kitchenware made of copper, or other voices claiming this fear is unnecessary and that these dishes and mugs are completely safe. Or, maybe you've never thought twice about it. Well…what's the deal?! Here we will clear up this mystery so you can feel comfortable and safe sipping on your refreshing Moscow Mule.
Copper Exposure and Health
Copper is a naturally occurring metal used industrially for electrical wiring, pipes, and other metal products and used agriculturally and in healthcare as an antimicrobial agent or contraceptive. Copper is an essential element, meaning that humans require some level of copper in our bodies(1). However, at high levels, (above 1,300 parts per billion), ingesting copper can irritate your digestive system and cause nausea, vomiting, stomach cramps, and diarrhea (2).
So, how are humans exposed to this metal? Like other metals, copper, when in contact with a liquid has the potential to leach off and become dissolved in the liquid. When consuming the liquid, any leached copper will be ingested and could cause the unfortunate digestive irritation mentioned above. The rate of this dissolution reaction depends on the properties of the metal, the properties of the liquid, and the temperature of these substances.
Copper in the kitchen is most commonly found in the form of mugs, or cookware like pots and pans. Copper kitchenware is sold either lined, meaning the inside is coated with a different, less corrosive metal, or unlined, where the item entirely copper. Going back to our fun chemistry lesson above, the potential to ingest copper at home (or at the bar!) comes from the possibility of the copper leaching into whatever substance you are cooking or drinking. So, the big question: Will the copper in your kitchen products leach and cause toxicity? In short, probably not.
Mugs – Although copper does leach faster than most metals used in cups, it would take many, many hours of sitting in the mug before your Moscow Mule became dangerous to drink (3). Of course, Moscow mules are not the only drink served in copper mugs, and other substances can behave a little differently. Most beverages are OK, but acidity and heat speed up the dissolution reaction (4). Something as acidic as lime juice would still take a few hours to leach, but to err on the side of caution, leaving hot and/or acidic substances in unlined copper dish ware should be avoided (3).
Pots and Pans – Because of the high temperatures used when cooking, unlined copper cookware should not be used (4)! The good news—nearly all copper cookware on the market is lined with a different metal. However, you can never be too careful! When cooking with copper items, make sure the inside is a different color, or that the label specifies "lined" to be certain that it is safe to use.
Pipes – The most common way humans are exposed to ingested copper is through tap water when copper faucets or storage pipes are used. If you are concerned about your water at home, run the water 15-30 seconds prior to drinking (2).
Our Advice
Don't fret about enjoying a drink out of a copper mug! If you are investing in new copper mugs, we recommend purchasing stainless steel-lined ones, but regardless there is no need to panic. If you have unlined mugs, just take care to ensure super hot or acidic substances don't sit in them for extended periods of time, and be extra cautious around children. As for pots and pans, invest in lined copper only. If you're on the market for some new copper kitchenware, here are some lined options pots, pans, and mugs. Now enough anxiety about copper, it's time to sit back, relax, and enjoy that Moscow mule!
Sources
1 https://medlineplus.gov/ency/article/002419.htm
2 https://www.atsdr.cdc.gov/ToxProfiles/tp132-c1-b.pdf
3 https://www.huffpost.com/entry/moscow-mule-not-poisonous_n_598c7552e4b0a66b8bb1938d?guccounter=1
4 https://accelconf.web.cern.ch/accelconf/p01/PAPERS/TPAH106.PDF
