Why Are Acidic Drinks So Refreshing When It’s Hot?

Answers to your questions about the news.
July 17 2013 2:43 PM

Why Do We Drink Lemonade When It’s Hot Out?

The role of acidity in quenching thirst.

Lemonade.
The acid in lemonade stimulates salivation, making you feel hydrated.

Photo by Thinkstock

A heat wave has many people in the eastern United States reaching for cold beverages such as lemonade and citrus-flavored soda. American settlers used to cool off with vinegar water. Why are sour drinks associated with refreshment?

Because they stimulate salivation. When you start to become dehydrated on a hot day, your body’s need for liquid manifests as a dry mouth. Research out of Japan in the 1960s showed that sour flavors stimulate salivation more than any other taste. Acidic drinks wet the mouth and give the impression of hydration even after your lemonade or vinegar water is finished.

Acidity also masks less refreshing flavors. Coca-Cola, another popular summer beverage, has a whopping 39 grams of sugar per serving. Those calories provide an energy boost on a hot day, but experiments suggest that sweetness is among the least refreshing flavors. Chilling the beverage to near-freezing temperatures and carbonating it help cover the sweetness, but it’s the acidity that makes cola palatable. The pH of Coca-Cola is approximately equivalent to that of vinegar. To fully experience how much acidity is required to offset high sugar contents, try chewing a piece of gum containing gymnemic acid, which binds to the sweetness receptors on your taste buds and blocks your perception of sugar. Then drink an acidic beverage. Your lemonade or cola will taste uncomfortably sour.

Advertisement

Conditioning is at play as well; we’ve learned to associate acidity with refreshment. Cleansers and air fresheners reek of lemon, and we probably make the connection between the clean smell in our dish soap and the flavor in our foods. Celebrity chef Mario Batali likes to refer to acid flavors as “bright,” and other cookbook authors use “fresh,” “perky,” and a range of other adjectives suggesting refreshment to describe the flavor of lemons. In 1975 taste researcher Howard Moskowitz showed that subjects from different cultures prefer vastly different levels of sourness, even though the preference for salt and sweetness is more universal, suggesting that our interest in sourness is largely learned.

We don’t seem to find acid refreshing in all forms and contexts. A 1998 study, for example, suggested that consumers find acidic beers less thirst-quenching. (Carbonation was the main driver of a beer’s refreshment level in the study.) It’s not entirely clear why the acid in beer failed to refresh, but it may have to do with how the researchers manipulated the acid levels. Vinnie Cilurzo, founder of Russian River Brewing Co., which makes some of America’s most popular sour beers, insists that simply adding acid directly to a beer creates “harsh” and “medicinal” flavors. Allowing bacteria to sour a beer naturally makes a smoother and more refreshing brew.

Got a question about today’s news? Ask the Explainer.

Explainer thanks Tom Finger of the University of Colorado, John Hayes of Penn State University, and David Labbe of Nestlé.

TODAY IN SLATE

History

The Self-Made Man

The story of America’s most pliable, pernicious, irrepressible myth.

The GOP Senate Candidate in Iowa Doesn’t Want Voters to Know Just How Conservative She Really Is

Does Your Child Have “Sluggish Cognitive Tempo”? Or Is That Just a Disorder Made Up to Scare You?

Why Indians in America Are Mad for India’s New Prime Minister

The Strange History of Wives Gazing at Their Husbands in Political Ads

Television

See Me

Transparent is the fall’s only great new show.

Doublex

Lena Dunham, the Book

More shtick than honesty in Not That Kind of Girl.

Rehtaeh Parsons Was the Most Famous Victim in Canada. Now, Journalists Can’t Even Say Her Name.

Parents, Get Your Teenage Daughters the IUD

The XX Factor
Sept. 30 2014 12:34 PM Parents, Get Your Teenage Daughters the IUD
Moneybox
Sept. 30 2014 12:04 PM John Hodgman on Why He Wore a Blue Dress to Impersonate Ayn Rand
  News & Politics
Jurisprudence
Sept. 30 2014 2:36 PM This Court Erred The Supreme Court has almost always sided with the wealthy, the privileged, and the powerful.
  Business
Building a Better Workplace
Sept. 30 2014 1:16 PM You Deserve a Pre-cation The smartest job perk you’ve never heard of.
  Life
Education
Sept. 30 2014 1:48 PM Thrashed Florida State’s new president is underqualified and mistrusted. But here’s how he can turn it around.
  Double X
The XX Factor
Sept. 30 2014 12:34 PM Parents, Get Your Teenage Daughters the IUD
  Slate Plus
Slate Picks
Sept. 30 2014 11:42 AM Listen to Our September Music Roundup Hot tracks from a cooler month, exclusively for Slate Plus members.
  Arts
Brow Beat
Sept. 30 2014 2:56 PM How Faithful Is David Fincher’s Gone Girl?
  Technology
Future Tense
Sept. 30 2014 2:38 PM Scientists Use Electrical Impulses to Help Paralyzed Rats Walk Again
  Health & Science
Bad Astronomy
Sept. 30 2014 7:30 AM What Lurks Beneath the Methane Lakes of Titan?
  Sports
Sports Nut
Sept. 28 2014 8:30 PM NFL Players Die Young. Or Maybe They Live Long Lives. Why it’s so hard to pin down the effects of football on players’ lives.