What’s Really in Your Soda? A Scientific Look at Sugar and Sweeteners

Why This Experiment Matters

Sugar is one of the most talked-about ingredients in soda, yet it’s often misunderstood. Labels may tell us what sweetener was added, but they don’t always tell us what that sweetener looks like after weeks or months inside an acidic, carbonated beverage.

In this video, a team from the Chemistry Department at Shippensburg University takes a closer look at how different sugars behave in soda — and what actually remains by the time a bottle is opened and enjoyed.

How Scientists Analyzed the Sugar

Chemistry professors Jeb and John, joined by their student Rebecca, used a high-performance liquid chromatograph (HLC) to separate and identify individual sugars present in soda samples. This lab technique allows researchers to see distinct sugar components such as glucose, fructose, and sucrose rather than relying on ingredient lists alone.

This approach provided a clear, science-based picture of how sugars change once they’re inside a carbonated, acidic environment.

What Happens to Sucrose Over Time

One of the most important findings from the video is that sucrose does not always remain intact in soda. In acidic conditions, sucrose can naturally break down — or hydrolyze — into its two components: glucose and fructose.

When a cane-sugar-sweetened cola was tested, researchers found nearly equal amounts of glucose and fructose, indicating that about 97% of the original sucrose had already broken down.

Testing Sugar Breakdown with Heat and Acidity

To better understand why this happens, the team conducted a controlled experiment using sarsaparilla soda to mimic similar acidity levels.

Their results showed:

• At 39°C, all sucrose disappeared within 14 days
• At room temperature, nearly half of the sucrose broke down in about three weeks
• 
  

These findings confirmed that temperature and acidity play a major role in how quickly sucrose changes inside soda.

A Surprising Discovery in Corn-Sweetened Soda

When sodas sweetened with high-fructose corn syrup were analyzed, researchers observed an unexpected sugar peak that did not appear in cane-sugar-sweetened samples.

This unidentified sugar — possibly a glucose-based compound such as maltose or other glucose oligomers — appeared at a concentration high enough to potentially influence flavor, highlighting that sweetness is more complex than just “fructose versus glucose.”

A Rare Cane Sugar Soda That Stayed Intact

One standout result came from a limited-edition soda made with cane sugar. Unlike other samples, much of its original sucrose remained intact, measuring roughly 64 grams per liter.

This revealed a unique sugar profile, different from both typical corn-sweetened sodas and cane-sugar sodas, where sucrose had already hydrolyzed — showing that formulation and storage conditions can dramatically affect the final product.

Does Sugar Chemistry Affect Taste?

To see whether these chemical differences translated to real-world experience, the team conducted blind taste tests with guests from Planet Money.

The results were mixed:

• Some participants correctly identified different sweeteners
• Others could not consistently tell the difference
• 
  

Economists also explained that cane sugar generally costs more than high-fructose corn syrup, largely due to agricultural pricing structures rather than flavor alone.

What This Means for Soda Lovers

This investigation shows that soda sweetness isn’t static. Time, temperature, acidity, and ingredients all influence what sugars are actually present when a soda is consumed.

For fans of traditionally made and craft sodas, this research reinforces the idea that how a soda is made — and how it’s stored — matters just as much as what goes into it.

Watch the Video

We invite you to watch the full video to see the experiments, chromatograms, and taste tests firsthand.