By Bridget Reed

Tart vs. Sour: What's the Difference?

In a land that hasn’t known the taste of sour since the day the Final Boss was banished for his evil crimes, Hank finds himself suddenly fighting a battle against a power he knows nothing about. Acknowledging that he’s out of his depth was hard enough, but admitting that he needs help from the terminally delightful Quinnie just about does him in.

Still, at every turn, she’s proven just how useful her sour expertise is in their battle — until today.

Hank asks Quinnie what the difference is between tart and sour, and Quinnie draws a blank. But then she starts to wonder. Do tart foods provide the same power boost as sour foods? If there’s a difference, could that be a helpful clue in their fight against the Final Boss

She realizes she needs to find out the difference for the sake of their mission (and not to mention her pride) and quickly sets off on a research mission to figure it out.

How Are Sour and Tart Different?

Quinnie knows that hot-headed Hank teamed up with her begrudgingly, and the last thing she wants is for him to decide he’s better off without her. She’s a valuable asset in the fight against their powerful foe and is determined to prove it yet again.

Quinnie tracks down her fellow quokkas who all possess their own potent powers of sour perception. She gathers the most clever of her quokka clan and finds that, unfortunately, nobody has a clear answer about the difference between tart and sour. But they all cheerfully offer to help her figure it out.

It turns out that her sunshine disposition is a common trait in her home country!

Similar, but not the same

First, they determine the foods people usually qualify as either tart or sour. Citrus fruits and fermented foods are usually considered tart, whereas yogurts and cheeses, wines and vinegars, and even some umami-rich foods tend to qualify as sour.

They decide to gather all these foods and utilize their keen sour perception powers to decide for themselves what the differences are. While they nibble and snack away at their pile of food, each quokka takes meticulous, thoughtful notes to compare when they’re done.

After compiling, analyzing, and averaging their data, Quinnie and her quokka compadres determine tart and sour frustratingly fall into the “same-same, but different” category. But not one of these sour experts is content with such an anticlimactic result, so they break it down by category.

Flavor Profile

The tart flavor is tangy and sharp on the tongue with a refreshing zest that functions like a perfect palette cleanser.

Sourness has a broader profile that seems to overlap with other tastes like bitterness and even occasionally umami. It has a noteworthy astringency that’s distinctly different from tartness.


Could the separation come from which acids exist in the food? Fermented foods get their tartness from lactic acid, but then again, so do sour yogurts and cheeses. The sourness of vinegar comes from acetic acid, but that also gives apples their special bite of tartness. 

That doesn’t seem to highlight much of a difference.

Taste Receptors

Everyone agrees that they taste tart flavors mostly at the tip of the tongue, whereas the sour flavor envelopes their whole mouths. 

Quinnie theorizes there must be a difference in taste receptors for each flavor and wonders if that could be her first clue in understanding the difference.

Health Benefits

Because a lot of tart foods are fermented, lactic acid plays a role in digestion support in the form of probiotics. But the same health benefit shows up in sour yogurts.

On the other hand, vinegar, which is rich in sour acetic acid, supports healthy blood sugar levels and can even balance insulin sensitivity. That’s a pretty impressive punch of sour power that Quinnie takes special note of.

Potential Weaknesses

Both tartness and sourness have some serious power-boosting potential, so the next thing for Quinnie to figure out is how to tone down the potency of their powers in hopes of potentially finding a new weapon to use against the Final Boss. The quokka crew brings their tart and sour foods into a kitchen and experiments on how to tamp down the flavor powers.

The tartness balances out well with a reasonable amount of sugar — and then they all enjoy the nice refreshing lemonade that they made in the name of research. They find that sourness calms down when it’s mixed with other flavors like bitterness and sweetness. 

So, whether or not tartness provides the Final Boss with the same power as sour does, Quinnie learns that adding a bit of sugar to the mix works to reduce the potency either way.

Research Mission: Complete

Quinnie makes her way back to Hank with more answers than she left with, feeling somewhat vindicated by learning there really isn’t all that much difference between tart and sour. But there are a few subtle differences, and the fact that so many others also don’t know the difference might just give them the slightest advantage in their battle.

They determine that they’ll sneak into the Final Boss’ territory and mix sugar into his sour food supply to reduce the potency of his sour power and maybe even swap out some of his sour foods for tart foods to see if that knocks him down a few pegs. 

Fingers crossed for our heroes on their next adventures.


The evolution of sour taste | National Library of Medicine

Sour taste: receptors, cells and circuits | National Library of Medicine

Fermented Foods, Health and the Gut Microbiome | National Library of Medicine

Vinegar supplementation lowers glucose and insulin responses and increases satiety after a bread meal in healthy subjects | National Library of Medicine