Seltzers, also known as sparkling waters, have become increasingly popular in recent years as a refreshing and lower calorie alternative to soda. With flavors ranging from classic lime to trendy options like black cherry or grapefruit, it’s easy to find a fizzy drink to suit any taste. But what happens if you accidentally leave your seltzer out in the sun or forget to refrigerate it after opening? Can seltzers actually go bad if they get too warm? Here’s a look at how heat affects carbonated waters and whether warm seltzers pose any risks.
Do unopened seltzers go bad at room temperature?
The good news is that unopened cans and bottles of seltzer are shelf-stable and should be fine at room temperature. Manufacturers create these beverages in sanitary conditions and seal them tightly to prevent contamination and maintain carbonation. As long as the can or bottle remains properly sealed, the seltzer inside should stay safe to drink even if stored for several months without refrigeration.
However, there are a few caveats to be aware of:
- Over time, unrefrigerated seltzer will lose some of its carbonation and go flat. The bubbles will dissipate faster in warm conditions. Storing seltzers in a cool, shaded area can help maintain fizz.
- If stored long enough, unrefrigerated seltzers may develop a metallic or cardboard-like taste as the ingredients degrade. This doesn’t make them unsafe, but affects flavor quality.
- Cans or bottles that become damaged, rusted, or swollen could be contaminated and should be discarded.
So while properly packaged seltzers don’t necessarily expire or go bad, you’ll get the best taste and texture by storing them chilled whenever possible. Letting seltzer sit out too long before drinking can make it lose its refreshing fizz.
Do opened seltzers go bad if left unrefrigerated?
Once opened, the story changes. Exposing seltzer to air allows microbes and bacteria to contaminate the beverage, which means an opened bottle or can shouldn’t be left unrefrigerated.
Bacteria grow rapidly in the nutrient-containing waters, sugars, and juices used to flavor many seltzers. Given time and warmer temperatures, they can produce gas, bloating the container or releasing carbonation. Visible signs of spoilage include:
- Bulging or leaking container
- Hissing sound upon opening
- Off odors
- Fizz that immediately bubbles over
- Slimy texture or stringy bubbles
- Unusual colors
- Mold
If you see or smell anything unpleasant, it’s best to discard the seltzer rather than drinking it. But how long do you actually have after opening before it goes bad?
| Beverage Temp | Time Before Spoilage |
|---|---|
| Room temperature (68–77°F/20–25°C) | 1–2 days |
| Warm conditions (77–90°F/25–32°C) | Within 1 day |
| Hot conditions (Over 90°F/32°C) | Within hours |
As shown, the warmer the temperature, the faster opened seltzer will become contaminated and develop off flavors. For best results, keep opened cans or bottles chilled in the refrigerator and finish drinking within a day or two.
Can heat damage or flatten the carbonation?
Carbonation gives seltzer its refreshing, tingling mouthfeel. But bubbles are delicate and can escape easily when heat is applied. Storing seltzer in warmer conditions allows carbon dioxide gas to come out of solution faster, flattening the drink. Signs of heat-related carbonation loss include:
- Less fizz and tingle on the tongue
- Softer or smaller bubbles
- Flat, watery texture
Excessive agitation can worsen these effects. Drops, kicks, or shaking a warm seltzer container will accelerate carbon dioxide escaping from the liquid. Short exposures to heat under 140°F (60°C) likely won’t completely flatten the drink, but may leave it less effervescent.
One experiment found that carbonation loss happened most rapidly above 86°F (30°C). After 6 hours at 86°F, seltzer retained around 80% of its fizz. But at 98°F, it lost about half its bubbles in the same timeframe. Higher temperatures can make seltzers go completely flat in a matter of hours.
Again, the effect is more pronounced once opened. The metal or plastic provides some insulation against heat before it’s unsealed. But an opened container lets gas escape more freely. Although flat seltzer is still safe to consume, the flavor and enjoyment is significantly reduced.
Can heat make seltzer unsafe or toxic?
While warm temperatures degrade the taste and fizz, seltzer doesn’t become toxic or hazardous when heated. The ingredients – carbonated water and natural flavorings – remain safe at typical storage conditions. There are a few circumstances where heat could potentially cause issues:
- Metal cans – Storing carbonated cans above 120°F could increase the risk of metal fatigue. This can lead to corrosion, cracks, or seam failures. Damaged cans may cut your mouth or leak dangerous contaminants.
- Plastic bottles – Letting plastic bottles get too hot could increase leaching of chemicals like BPA into the seltzer, especially if left in direct sun. This is more of a concern in older, scratched bottles.
- Fire risk – Cans or bottles that get extremely hot can rupture and spray contents rapidly. This poses a minor fire risk if the seltzer sprays onto an open flame or sparks.
However, these scenarios require quite extreme heat beyond just leaving a seltzer on the counter overnight. As long as it’s stored safely, brief warmth won’t make seltzer toxic or hazardous to drink.
Tips for keeping seltzer from warming
Here are some tips for keeping opened and unopened seltzers cool and preventing carbonation loss:
- Refrigerate after purchase and store any extras in back where it’s coldest
- Keep fridge set to 40°F or below
- If refrigeration isn’t possible, add seltzer to cooler with ice packs
- Avoid storing cans or bottles directly in sunlight
- Consume refrigerated seltzers within 1-2 days of opening
- Don’t let seltzer sit out more than 6-12 hours after opening
- Purchase smaller bottles or cans to finish quickly after opening
- Avoid shaking or agitating warm seltzers
- Keep spares in garage or basement where it’s cooler if fridge space is limited
Proper chilling helps seltzers hold their carbonation and taste refreshing. But the most important rule is to trust your senses. If the seltzer looks, smells or tastes off after sitting out, it’s better to be safe and throw it away.
The shelf life of popular seltzer brands
Shelf life can vary slightly depending on the brand, ingredients, and packaging. Here are some general guidelines for how long popular seltzers last:
LaCroix
- Unopened – 3-6 months in pantry, over 1 year in fridge
- Opened – 2-3 days in fridge
Perrier
- Unopened – 1 year in pantry, indefinitely in fridge
- Opened – 3-5 days in fridge
Spindrift
- Unopened – 10-12 months in pantry, over 1 year in fridge
- Opened – 3-5 days in fridge
Polar Seltzer
- Unopened – indefinite in pantry and fridge
- Opened – 5-7 days in fridge
Bubly
- Unopened – 18+ months in pantry, indefinite in fridge
- Opened – 1-2 days at room temp, 3-5 days in fridge
The bottom line is that unopened, factory-sealed seltzers stay fresh for many months in cool, dry storage. But consume opened cans and bottles quickly within 1-5 days for optimal taste and fizz.
Can you re-carbonate seltzer that has gone flat?
It is possible to revive some of the carbonation in seltzer that has started going flat using a home carbonation system like a SodaStream. Here’s how:
- Empty the warm, flattening seltzer into a carbonating bottle
- Add fresh water to fill line in bottle
- Carbonate with CO2 system per device instructions
- May require a few cycles to re-carb fully
- Consume immediately before bubbles dissipate again
This technique infuses more bubbles into the liquid. However, it won’t restore the seltzer’s flavor if it has already become spoiled or bad tasting. And repeatedly carbonating and decarbonating a seltzer can degrade quality over time.
A simpler option is to pour the flat seltzer over fresh ice. The colder temperature helps bubbles remain suspended in the liquid for a bit longer. Add a squeeze of citrus for an extra refreshing flavor. But it’s still best to drink the seltzer sooner than later, before the fizz is gone completely.
Conclusion
Seltzers can gradually lose their carbonation and start to go flat when stored in warm conditions, especially after opening. While sealed cans and bottles are shelf-stable at room temperature, the bubbles dissipate faster without refrigeration. Opened containers should be refrigerated and consumed within a few days to retain the best quality.
However, seltzer doesn’t necessarily spoil or become hazardous to drink if it gets warm. As long as it hasn’t become contaminated with mold or bacteria, flat seltzer is still safe to consume. But the enjoyment of drinking it declines significantly without the refreshing fizz.
Storing seltzers chilled, avoiding heat exposure, and finishing opened containers quickly are the best ways to prevent carbonation loss and flat, lifeless drinks. With proper handling, seltzers can maintain their satisfying bubbles and flavor.
