Serious Eats: Drinks
Cocktail Science: Is Tap Water Ruining Your Homemade Cocktails?
You find an amazing cocktail at a bar, get the recipe, and try it out at home. But, no matter what you do, your home version tastes flat, boring, or just plain off. Your mixing skills might be to blame, but what if the real problem lies in a cruddy water source? Here's how to find out.
Before anything else, do this.
Run, do not walk to your kitchen sink. Pour yourself a glass of cool tap water. Does it taste awesome? Like cool morning dew clinging to the underside of a blade of unadulterated grass?
Then leave your water alone.
The United States maintains respectably high standards for drinking water. In fact, the Environmental Protection Agency enforces higher standards for tap water than the Food and Drug Administration uses for bottled water.
So why worry about tap water?
Because the government cares that your tap water is safe to drink, not that it tastes awesome. Plus, the government only controls centralized water sources, and as resident Food Lab expert Kenji Lopez-Alt has pointed out, the water coming out of your tap can be contaminated by the very pipes in your home.
How Much of a Difference Can Water Really Make?
If you've ever traveled around the United States, you've probably noticed a strange sensation: sometimes soap feels more slippery when you shower.
What's going on?
- Soap reacts with the "hard-water" minerals magnesium and calcium to create soap scum.
- People install water softeners that replace those minerals with sodium and potassium.
- Sodium and potassium don't form soap scum, but they will react with soap to create a "slippery" film on your body.
Here's the so what: a measurement of just 160 parts per million (ppm) or mg/L* total dissolved solids (TDS) means you've got hard water. The EPA, on the other hand, considers a TDS of up to 500 mg/L acceptable of drinking water.
If a 160 TDS reading can mean the difference between slippery or squeaky skin, imagine what 500 TDS can do to your tongue.
What's the solution? Well, filter your water, of course. But the question then becomes: how filtered?
*In water at sea level, ppm comes out to the same thing as mg/L though that's not always true in other situations.
Myth: The Best Water Tastes Like Nothing.
Distilled water? Been there, done that, kinda sucks.
People associate the best water with being 100% free of contaminants, but that's not strictly true. By definition, distilled water has had all its impurities chemically removed. By itself, it doesn't exactly taste bad, but it doesn't taste good either.
Here's another big problem with distilled water. Water with absolutely zero minerals in it is highly reactive, which means it quickly absorbs impurities from whatever it touches. That's why high school chemistry students associate distilled water with that weird "paper cup taste."
So if distilled water doesn't taste amazing, what water does taste best?
Why I'm Obsessed with Spit
If distilled water doesn't taste like "nothing," what does?
The answer, as it turns out, is saliva.
Since our natural saliva occupies our mouths all the time, we naturally become adapted to its taste. What's adaptation? Think about this: what happens when you taste something sour and then sip water? The water tastes sweet. When the tongue adapts to vinegar, less-acidic water tastes sweet for a few moments.
Saliva is the baseline you're permanently adapted to; you experience the taste of all other liquids only as they compare to that baseline.
So what does that baseline look like? Saliva contains a viscous mix of digestive enzymes, proteins, and most importantly, the minerals sodium, potassium, calcium, and magnesium, among others. Oh, and its pH (acidity) is roughly neutral, though it varies depending on what you've been drinking.
That's why distilled water tastes weird: compared to saliva, it's lacking in key minerals. Hence, the "off" taste.
After I figured this stuff out about saliva, I realized that truly good tasting water must contain minerals, and probably in concentrations similar to what's found in human spit.
The pros, it turns out, were way ahead of me.
Look carefully at the label of any bottled water you might buy and information should be provided about that water's mineral concentrations. You see, most water-bottlers don't actually collect water directly from streams or "glaciers" (wtf?), they actually filter everything out of a decent water source and then add minerals back into the water for taste.
What minerals? The ones most prominently found in saliva.
"Perfect" Water: Lessons from the Coffee and Tea Folks
When I was researching my book, I found several bottled water taste tests that all pointed to one conclusion:
A total dissolved solids level of around 35 mg/L tastes the best.
And what minerals made up those dissolved solids? Not to beat a dead horse, but they were sodium, potassium, calcium, and magnesium. To read way more about the science of water and minerals, check out this excerpt from my book on Camper English's Alcademics blog.
For coffee, the experts seem to agree that a higher TDS level is ideal. In a taste test between 45 mg/L, 150 mg/L, and 450 mg/L water for brewing coffee, experts unanimously chose the 150 mg/L sample as ideal.
The tea folks seem to have settled on a similar range: between 50 mg/L and 150 mg/L is considered a good range.
And both the coffee and tea folks agree that using artificially softened water will change the extraction profile of the final beverage.
How to Hack "Perfect" Water
I started on this crazy project after noticing that the water from my tap made homemade cocktails taste... off.
Even though no water is directly added to a cocktail, ice melt can be significant. In my tests, water due to ice melt made up roughly 40% of the total mass of a cocktail.
When I tested my home water source, I found that the water straight out of my tap came in at a whopping 300 TDS and a slightly acidic 6.8 pH.
To test your own water,
- Consider buying a simple TDS meter
- You can buy a pH meter as well, but I've found that they're hard to use, unreliable, and aren't as useful in detecting problems as a TDS meter.
- Ultimately, let your nose (and tongue) be the judge.
- Most home models use activated charcoal, which captures most minerals and chlorine. Some varieties are more effective than others.
- Activated charcoal works poorly against dissolved metal ions (like lead or sodium). Reverse osmosis (RO) can deal with these contaminants, though effectiveness depends on the membrane size used in the RO system.
- Multi-stage filters are designed to remove the most common contaminants step by step.
So what's the best approach? Honestly, it depends on your water source. You might do fine with a simple charcoal-based filter. In my case, my water had high levels of sodium, so I went with a 5-stage ZeroWater system. Unfortunately, these filters are slow and can be expensive.
A Recipe for Water?
As I alluded to earlier, the highest-rated water generally contains a small concentration (around 35 TDS) of sodium, calcium, and magnesium. The most widely-available brand of water that fits this bill is SmartWater, a bottled water that is nothing more than distilled water with minerals added back in.
To make a replica at home, simply start with distilled water (you can get it in gallon or larger sizes at Walmart or use a combination of filters to get 0 TDS water) and add a very small amount of sodium bicarbonate (baking soda), calcium chloride, and magnesium chloride to the mix.
Want to read more?
I was specifically interested in finding out what basic water tastes great to most people. But, there are some amazing folks out there exploring the boundaries of what you can do with water. For example:
- Chemist/bartender Darcy O'Neil writes about mineral waters, their taste, and how to make them at length in his must-read book Fix the Pumps.
- Organic chemist/food blogger Martin Lersch provides an overview of mineral waters and handy calculator that tells you exactly how to recreate your favorite brand's flavor.
- And most recently, popular cocktail blogger Camper English has partnered with Bowmore distillery to learn about the waters that form the foundation of great Scotch. This series is fascinating, particularly for lovers of neat spirits.
What's your favorite bottled water? What else do you want to know about water?
About the author: Kevin Liu likes to drink science and study cocktails. Wait, that's backward. Ask him geeky food and booze questions on twitter @kevinkliu. While you're at it, check out his book about cocktail science and his blog about food and science