What Makes Soda Go Flat Faster? (Keep It Fizzy)

Besides the sweet, sugary rush, we love soda for its fizz. It’s like champagne for kids. But taking an anticipatory gulp of ice-cold soda turns into disappointment when you find the bubbles are gone – and the bottle’s only been open for a couple of days. What makes soda go flat faster?

Soda will go flat faster when you allow the carbon dioxide gas that causes the fizz to escape. Soda loses its fizz if it is incorrectly stored: the container isn’t well-sealed, the temperature is too high, or the container is plastic. Shaking and stirring soda will also cause flatness.

Carbon dioxide gas gives soda its bubbles, so the key to keeping your drinks fizzy is to stop the gas from escaping. Let’s look at how to stop the fizz from fizzling out and avoid your soda going flat too quickly.

Why Does Soda Go Flat?

Soda goes flat because the carbon dioxide gas that forms the taste-bud tickling bubbles escapes.

To make soda, manufacturers use pressure to force carbon dioxide into soda, which is why fizzy beverages are called “carbonated” soda. 

During carbonization, the soda is kept at very low temperatures, as colder liquid stabilizes and dissolves the carbon dioxide more quickly than warm water (like sugar dissolves in hot coffee). 

Adding gas under pressure allows the soda to become super-saturated, filling the space above the liquid. The carbon dioxide gets locked in when the bottle or can is sealed.

As soon as you open the soda, the pressure is released, and the carbon dioxide rushes out, creating the characteristic hissing sound.

The bubbles you can see when pouring the soda are carbon dioxide fizzing out. 

Unless you seal the soda again, the carbon dioxide will keep dissipating until it is all gone. A soda with no gas bubbles is called flat soda.

Flat soda tastes unappealing because of the lack of fizz and a change in flavor. Carbon dioxide creates carbonic acid in the soda, giving it a characteristically zesty taste. The carbon acid and tangy flavor are lost as the gas dissipates.

Does Shaking Soda Make It Go Flat?

Shaking soda makes it go flat more quickly because you are helping the carbon dioxide to escape faster.

Shaking a soda mixes the air above the liquid with the carbonated drink, causing bubbles where the carbon dioxide clusters together. More and more bubbles combine, making it easier for the gas to escape from the liquid. 

However, if the container is closed, the gas bubbles are trapped, increasing the pressure inside.

Once you open the can or bottle, the carbon dioxide can escape, frothing and spilling out, leaving you with a flat, lifeless beverage. It can take several hours for a shaken soda to settle before opening it.

Do Warmer Temperatures Make Soda Go Flat Faster?

Soda goes flat more quickly when it’s warm because the liquid can’t hold the carbon dioxide – the gas dissolves in liquid at lower temperatures.

As the soda gets warmer, the gas escapes from the liquid, leaving it flat.

However, if the soda is sealed in cans or unopened bottles, the temperature will only cause gas to escape after a very long time as it still has to escape through the container and its seals.

Does Soda Go Flat Faster In The Fridge?

Soda does not go flat faster in the fridge like some people think. Instead, refrigerated soda will keep its fizz for longer.

Soda remains fizzier in the fridge because colder liquids retain carbon dioxide better than warm liquids, as the gas dissolves more easily. More gas means more bubbles, which is why cold soda tastes much better than warm soda.

If you have opened a bottle of soda, store it in the fridge with the lid tightly sealed. Leaving the cap open will allow the carbon dioxide to escape, even if the liquid remains cool.

Does Ice Make Soda Flat?

Ice can make soda flat because of the motion of adding ice into or pouring the soda. This motion has the same effect as shaking, causing the carbon dioxide and outside air to create clusters of bubbles that allow the gas to escape.

This makes the drink a little flatter in the short term, but ice is good in the long run as it keeps the drink cold. If you’ve ever had a drink without ice, forgotten about it then return to take a sip, it’s usually warm and flat.

Ice will make soda flat even faster if it is cloudy. Cloudy ice comes from water that contains trapped air bubbles, which attract the carbon dioxide in the soda. As soon as the soda and ice touch, the gas escapes, fizzing and frothing.

Clearer ice will keep a soda fizzy for longer as it has no air pockets or bubbles, so the carbon dioxide doesn’t cluster around it. The gas will slowly escape as the liquid is exposed to air.

Drinking your soda without ice helps keep your beverage bubbly if you are to drink it quickly without it getting warm.

How Long Does Soda Take To Get Flat?

How long your soda will stay fizzy and tasty depends on whether it is opened, how you store it, and what brand it is.

How Long Does Unopened Soda Take To Get Flat?

Unopened soda will get flat in 6 to 9 months or longer as indicated on their “best before” dates.

The USDA says you can drink unopened diet sodas within 3 months after the date expires and regular sodas within 9 months – they are classed as “not perishable” but still go flat and taste bad.

If soda is unopened, the pressurized carbon dioxide remains trapped inside. Unopened soda keeps its effervescence the longest.

Soda stored in glass bottles or cans lasts longer and can have up to a one-year shelf life. After this, you’ll find that the soda may still be fizzy, but the flavor will deteriorate, especially in poor-quality brands.

If you’ve got soda in plastic bottles, the fizz lasts for 6 months or so. Although the plastic lids lock in the carbonation, the gas eventually escapes. Plastic is also very slightly permeable.

It’s worth noting that “diet” drinks last a shorter time as the artificial sweetener loses its flavor and breaks down.

Store your soda in a cool pantry or cupboard, out of direct sunlight. 

How Long Does Opened Soda Take To Get Flat?

Once your soda is open, the carbon dioxide will start escaping immediately, giving it a short shelf life of three to five days if stored well.

An open can of soda or bottle without a lid will remain fizzy for two to three days if you store it in the fridge. 

However, the soda will go flat within a day at room temperature.

Although you can’t reseal a plastic bottle of soda as tightly as the manufacturer, closing the lid helps keep the soda bubbly for longer. 

A bottle of soda in its original bottle and lid will go flat after two to five days if stored closed at room temperature. Keeping the soda in the fridge will extend its shelf life to four or five days.

How To Purposely Decarbonate Your Drink

If you enjoy your sodas without the pop, you can make them go flat faster. It’s perfectly safe to drink flat soda and might even be better for you as I covered in a previous article.

Leave Your Soda Open 

If you’re not in a rush to drink the soda, open it, and leave it at room temperature.

Leaving the soda in a sunny spot will speed up the process of the gas escaping naturally.

The soda will lose its fizz within a day.

Stir Your Soda

An easy way to decarbonate soda is to stir it.

Stirring the soda mixes air into the liquid, causing bubbles with surfaces that attract the carbon dioxide, enabling it to escape the soda.

The stirring motion also forces more bubbles to the surface, releasing carbon dioxide.

Heat Your Soda 

Another method of making soda flat quickly is to heat it. 

Pour the soda into a saucepan and heat it low on the stovetop, stirring with a whisk. 

Combining heat and stirring will turn the soda flat very quickly, within a couple of minutes.

Once flat, put the soda in the fridge to cool it down before drinking it.

Note that heating soda can change the flavor a little so don’t overdo it.


Hopefully, you now know what makes soda flat faster. Soda goes flat when the carbon dioxide bubbles escape. As soon as you open a soda, the gas starts leaking out, so keep the soda unopened or tightly closed as long as possible. Avoid shaking or stirring the beverage, and store it in the fridge to keep it fizzy and refreshing.

Tom Hambly

Tom Hambly is the founder of Totally Drinks. He loves to cook and drink nice things - his favorite drinks are wine, beers and whiskey. About Tom Hambly.

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