You found a few cans of root beer pushed to the back of the pantry, well past the date stamped on the bottom, and you’re wondering if it’s safe to crack one open. Unlike milk or meat, soda doesn’t carry the same spoilage risk, so the question isn’t really about safety. It’s about whether it still tastes like root beer.
Does root beer go bad?
The short answer: Not in the way perishable food does. Root beer is a sealed, carbonated, acidic beverage, and that combination makes it inhospitable to the bacteria that cause foodborne illness. What actually happens over time is that it goes flat and the flavor fades, especially once the can or bottle has been opened. The date on the package is a quality estimate, not a safety cutoff, per USDA’s general guidance on food dating.
For a complete pantry storage reference, see our Food Storage Guide.
đź“‹ Does Root Beer Go Bad: At a Glance
| Unopened, pantry | Safe past the printed date; expect less fizz and duller flavor over time |
| Opened, refrigerated | Best within a day or two for carbonation; safe longer, just flatter |
| Bulging, rusted, or leaking can | Discard without opening, regardless of the date |
| Caffeine | Most brands are caffeine-free; Barq’s has 22mg per 12 fl oz |
Key Takeaways
- Root beer doesn’t spoil the way perishable foods do. Carbonation and acidity make it an unfriendly environment for the bacteria that cause foodborne illness.
- What actually changes with age is quality: the carbonation dissipates and the flavor fades, especially in a can or bottle that’s already been opened.
- An unopened can or bottle typically holds its best quality for months past the printed date; that date reflects flavor and fizz, not a safety deadline.
- Most root beer is naturally caffeine-free. Barq’s is a notable exception, with 22mg of caffeine per 12 fl oz can, per Barq’s own website.
- Root beer’s flavor traces back to sassafras root, but the safrole compound that federal regulation puts at about 80% of sassafras oil has been banned from U.S. food since 1960, so modern root beer uses safrole-free flavoring instead.
Why Root Beer Doesn’t “Spoil” Like Food Does
Root beer is built on the same basic preservation logic as most sealed soft drinks: carbonation, acidity, and sugar content together create conditions that bacteria and mold struggle to grow in. As long as the can or bottle stays sealed, there’s no real pathway for contamination to get in. That’s why soda is shelved at room temperature right alongside other shelf-stable pantry goods rather than in a refrigerated case.
What you’re actually watching for with an old can of root beer isn’t bacterial spoilage, it’s a slow decline in quality. Carbon dioxide gradually escapes through the can or bottle seal over months and years, even when it’s never been opened, so a soda that’s been sitting for a long time pours flatter than a fresh one. The sugars and flavoring compounds also shift subtly over very long storage, which is why an old can can taste a little duller or “off” in a vague way without being unsafe.
The Date on the Can: Quality, Not a Safety Deadline
The date stamped on a can or bottle of root beer isn’t a legal safety requirement. Per USDA’s general guidance on food product dating, “best if used by” and similar dates indicate peak flavor and quality, not a safety cutoff. Except for infant formula, dates aren’t required by federal law at all. If the date passes while a sealed can is sitting in your pantry, it should still be safe; you’re just more likely to notice it’s lost some fizz or flavor sharpness.
Why Carbonation Fades Even in a Sealed Can
Cans and bottles aren’t perfectly airtight at the molecular level, so over long stretches of time, carbon dioxide gradually works its way out through the seal. Plastic bottles lose carbonation faster than aluminum cans or glass, since plastic is naturally more permeable to CO2. That’s part of why a two-liter plastic bottle of root beer that’s sat around tends to go flatter sooner than an unopened can would. Nothing about this process makes the drink unsafe; it just means a soda that’s been stored for a long time won’t be as bubbly as one bought last week.
Once You Open It: Flat Is the Main Enemy
After opening, root beer loses its remaining carbonation fast, usually within a day or two in the fridge, faster at room temperature. There’s no food-safety reason to refrigerate an opened can immediately the way you would with dairy or meat, but keeping it cold does slow the loss of fizz somewhat and keeps the flavor fresher for longer. A resealable bottle cap helps more than a loosely re-covered can, since it limits how much carbon dioxide can escape.
This matters most if you’re the type to pour a glass and leave the rest for later rather than finishing the bottle in one sitting. Recapping tightly and refrigerating it is the best way to keep it drinkable rather than flat by the time you come back to it. And if a glass gets knocked over in the meantime, root beer’s dark color means it can leave a mark; see our guide on getting soda stains out of clothes.
Root Beer for Entertaining: Common Mixers and Pairings
Root beer’s vanilla and caramel notes make it a popular mixer for dessert-style cocktails, which is one more reason you’ll often open a bottle and only use part of it at a gathering. Vanilla vodka poured into root beer is the simplest version of a boozy root beer float, and swapping in Kahlua gets you closer to a root beer white russian. RumChata is another common partner, since its cinnamon-and-cream profile plays well against root beer’s sweetness, and spiced rum, Captain Morgan being the usual pick, shows up in root beer cocktails for the same reason. If you keep any of these open behind the bar for mixing, they each hold up differently than the soda does. Vodka and rum have a much longer open shelf life than root beer does. RumChata and KahlĂşa are closer to the soda’s own timeline, and RumChata’s label specifically calls for using it within about 6 months of opening. Check each spirit’s own post for specifics rather than assuming they all behave the same once the bottle’s open.
Signs Something Is Actually Wrong
- Bulging or swollen can: A sign of internal pressure buildup or possible contamination. Don’t open it; discard it.
- Rust, leaks, or a damaged seam: The seal may be compromised. When in doubt, throw it out.
- Mold or visible particles floating in the liquid: Not a normal quality-fade issue. Discard.
- A sharply off, sour, or chemical smell or taste: Uncommon in sealed soda, but if it happens, don’t drink it.
Normal Changes That Don’t Mean It’s Bad
- Less fizz than when it was fresh, even in an unopened can.
- A flavor that tastes slightly duller or flatter than a brand-new bottle.
- Minor condensation or a damp can from cold storage, which has no bearing on what’s inside.
A Short History, and What’s Actually in the Bottle
Root beer’s commercial origins trace back to 1875, when pharmacist Charles Hires developed a “root tea” from sassafras and other roots. He debuted it as “root beer” at the 1876 Centennial Exposition in Philadelphia, reportedly renaming it to appeal to Pennsylvania coal miners. A&W followed decades later: Roy Allen opened his first root beer stand in Lodi, California, in 1919, and partnered with Frank Wright in 1922 to build out what became the A&W brand.
Root beer’s flavor historically came from sassafras root, which contains safrole, a compound the FDA has banned from U.S. food since 1960, after studies found it caused liver damage and acted as a carcinogen in rats. The same regulation states that oil of sassafras is about 80% safrole, which is close to the whole oil rather than a minor component of it. Rather than relying on the raw plant, the FDA separately permits a purified, safrole-free sassafras extract. That’s what modern commercial root beer draws on, often alongside artificial sassafras-style flavoring, to keep the traditional flavor while meeting current food-safety regulations.
Root Beer’s Caffeine Content
Most major root beer brands are caffeine-free by design; A&W Root Beer, for instance, is consistently labeled “caffeine free” on current retail packaging. Barq’s is the well-known exception: per Barq’s own website, it has 22mg of caffeine per 12 fl oz can, roughly two-thirds of the 34mg in a same-size can of Coca-Cola Classic. If caffeine content matters to you, it’s worth checking the specific can’s label rather than assuming, since this varies by brand.
Quick Storage Reference
- Unopened, pantry: Store cool and dry. Holds best quality for months past the printed date; not a safety concern once that date passes.
- Opened: Reseal tightly and refrigerate to slow carbonation loss. Best consumed within a day or two for fizz, though it stays safe longer.
- Damaged can or bottle: Discard regardless of date, bulging, rust, or a compromised seal.
| Situation | What to Do |
|---|---|
| Unopened can past its printed date | Safe to drink; expect somewhat less fizz and flavor sharpness. |
| Opened bottle, a day or two old, refrigerated | Safe; likely noticeably flatter but still drinkable. |
| Can is bulging, rusted, or leaking | Discard without opening, regardless of the date. |
| Checking caffeine content | Read the specific brand’s label; don’t assume based on other root beers. |
Does Root Beer Go Bad FAQ
Can old root beer make you sick?
Unlikely, as long as the can or bottle was sealed and undamaged. Root beer’s carbonation and acidity aren’t friendly to the bacteria that cause foodborne illness, so an old soda is far more likely to just taste flat than to make you ill. A bulging, leaking, or rusted can is the exception, since that signals the seal may be compromised.
Does root beer go bad after the expiration date?
It doesn’t go bad in a food-safety sense. See “The Date on the Can” above: per USDA’s general dating guidance, that date marks peak quality, not a safety deadline. A sealed can or bottle should still be safe past it, just possibly flatter or less flavorful.
Why does old root beer taste flat?
Carbon dioxide slowly escapes through the can or bottle seal over time, even when it’s never been opened. See “Why Carbonation Fades” above. It’s a gradual physical process, not a sign of spoilage.
Does root beer have caffeine?
It depends on the brand. Most major root beers, including A&W, are caffeine-free. Barq’s is the notable exception, with 22mg of caffeine per 12 fl oz can on its own label. Check the specific can if caffeine matters to you.
Can you freeze root beer?
It’s not a good idea. Water expands as it freezes, and that expansion pushes against the can or bottle at the same time the dissolved carbon dioxide is trying to escape, which can crack a bottle or split a can. It’s more of a mess-and-waste problem than a safety hazard, but it’s still worth avoiding; the fridge, not the freezer, is the right place for a root beer you want cold fast.
Further Reading
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