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Is your Moscow Mule poisoning you? Recent news says acidic drinks in copper mugs can leach copper. I grabbed pH strips and tested every ingredient.
Copper mugs are a big part of the Moscow Mule’s popularity. The concern is that liquids more acidic than neutral (below 7 on the pH scale) draw copper into the drink, and then you drink it. A Moscow Mule only has three ingredients, so I wanted to know which ones make it acidic. This is for entertainment, not a lab test. The button goes to copper mugs lined with stainless steel, so the drink never touches the copper.
- Neutral is 7; anything lower is acidic
- Vodka alone tested about neutral
- Plated or lined mugs keep copper out of the drink
- Stainless steel mule mugs are another option
- The Mule tested clearly acidic (3 to 4)
- Ginger beer, the biggest ingredient, is acidic
- Lime juice is very acidic
- Strip readings are rough, and my lighting wasn’t great
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The pH scale in 30 seconds
Seven is neutral. Water and milk sit right around there. Anything below 7 is acidic, down toward 0 or 1 for full-on acid. Above 7 is basic or alkaline, which includes things like bleach, which I didn’t know.
The claim is that a Moscow Mule comes in at 6 or below, which could be a problem in a pure copper mug, especially if you drink them a lot.
The test kit
I ordered a universal pH test strip kit on Amazon. You might remember these from high school: wet the end, it changes color, and you match it to the color scale from 1 to 14.
As a control, I tested regular bottled water. I expected 7, but it looked more like 6 to me, so maybe the water around here is a little acidic anyway.
Testing a Moscow Mule
I made a small one: a little Polish vodka, mostly Trader Joe’s ginger beer, and some generic lime juice from my local grocery store. My percentages might be a little off.
The strip turned bright orange right away. It looked like a 3 or 4, probably closer to 4. Definitely acidic.
Which ingredient is the problem?
Ginger beer turned orange right away too, about a 3 or 4. Since it’s the biggest part of the drink, it’s probably the biggest contributor.
Lime juice turned the brightest orange yet, close to red, so about a 1 or 2. Very acidic.
Vodka turned a light green, about a 7, right in the middle. So vodka alone in a copper mug is probably fine. But with only a shot or two in the drink, it doesn’t change the overall mix much, and with two acidic ingredients, the Mule ends up acidic.
So, are copper mugs safe?
Drinking a Moscow Mule out of a pure, unlined copper mug doesn’t look like a safe thing to do. If the mug is plated or lined with something else, the copper won’t leach into the drink.
Stainless steel Moscow Mule mugs also became really common when copper prices were high, and I might pick up a set of those. If you love the copper look, a copper mug with a stainless steel lining gives you both.
FAQ
Are copper Moscow Mule mugs safe?
Acidic drinks can leach copper from unlined copper. Plated or lined mugs keep the drink off the copper.
What pH is a Moscow Mule?
My strip test read about 3 to 4.
Which ingredient is most acidic?
Lime juice, about 1 to 2 on my strips, followed by ginger beer at about 3 to 4.
Is vodka acidic?
My vodka tested about 7, roughly neutral.
What mug should I use?
A copper mug lined with stainless steel, or a stainless steel mug.
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