Why Is My Wine Fizzy? Normal Prickle or Refermentation

Why Is My Wine Fizzy?

A still wine fizzes for one of two reasons. The winemaker may have left a little carbon dioxide in it to keep it fresh, which is harmless. Or yeast or bacteria restarted fermentation inside the sealed bottle. That fault is refermentation, and it shows up as fizz usually alongside haze, sediment and a yeasty or sour smell.

What you notice	Likely cause	Drink or return?
Faint prickle only; wine clear and bright; smells fresh	Carbon dioxide left in on purpose, common in young whites, rosés and light reds	Drink. Swirl or wait ten minutes if you want it calmer.
Bubbles plus haze through the whole glass; yeasty or beery smell; maybe a fine deposit	Yeast refermenting leftover sugar	Return it. It will not improve.
Bubbles plus haze or sediment in a wine that should be crisp and dry, red or white; creamy or sour-milk note	Malolactic fermentation restarting in the bottle	Return it.
Cork pushed up or leaking; hiss on opening; wine spurts	Pressure from refermentation (heat damage can also push a cork)	Chill it, open it pointed away from people, then return it.
Fizz plus vinegar, nail-polish or barnyard smell	Volatile acidity or Brettanomyces, spoilage faults that can share a bottle with refermentation	Return it if the smell dominates.
Small clear crystals at the bottom, no bubbles	Tartrate crystals, harmless	Drink. Decant off the crystals if you like.
Gentle bubbles, sometimes cloudy, under a crown cap; label says pét-nat, frizzante or Vinho Verde	Deliberate style	Drink, well chilled.

Sediment on its own is not a fault. Aged reds and unfiltered wines drop deposits naturally, and wine sediment explained shows how a settled deposit differs from a wine cloudy all the way through. Tartrate crystals are tartaric acid salts that fell out of solution in the cold. For the smell column, how to identify wine faults by smell gives the vocabulary, with separate guides to Brett in wine and volatile acidity.

Is a Little Fizz in Still Wine Normal?

Often, yes. Many winemakers deliberately leave a small amount of carbon dioxide in young white and rosé wines to keep them tasting fresh. Wine Spectator's Dr. Vinny notes that winemakers sometimes add an extra dose of carbon dioxide right before bottling. You often notice it in crisp young whites such as Sauvignon Blanc, Grüner Veltliner and dry Riesling, and in pale rosé.

The law draws the line by pressure. Under EU Regulation 1308/2013, a semi-sparkling wine (frizzante on an Italian label) holds an excess pressure of 1 to 2.5 bar at 20°C, and a sparkling wine at least 3 bar. A faint prickle below 1 bar leaves a wine still, in law and in the glass.

Temperature changes how much of that gas you notice. Carbon dioxide is less soluble in warm wine, so a bottle poured straight from the fridge can seem to gain prickle as it warms in the glass. Swirl it and wait ten minutes, and a deliberate prickle fades. More on what serving temperature changes: how temperature affects wine taste.

Quick check

One question on what you just read

Your young white has a faint prickle but looks clear and smells fresh. What is it most likely?

AYeast restarted in the bottleBCork taint from the closureCA touch of gas the winemaker left in

Tap an answer to see how you did.

Is Fizzy Wine Safe to Drink?

Yes. VinePair says it directly: "a little bit of fizz in your red wine won't hurt you." Refermentation spoils the taste; the real risk is pressure. The Australian Wine Research Institute (AWRI) warns that wines above 10 g/L of residual sugar may explode if they referment.

A cork that has crept up, a bulging capsule or a hiss as the seal breaks all mean pressure has built. Chill the bottle first, which lowers the pressure. Then open it slowly with a towel over the top and the neck pointed away from faces, the way you would open sparkling wine. If a bottle has already burst or is bulging, see what to do when a wine bottle explodes. A pushed cork can also mean heat damage, a separate fault with its own signs.

Drinking it is a question of taste. The yeast ate sugar, which VinePair notes "might have altered the flavor or balance of the wine overall." A refermented wine usually tastes yeasty and off balance, and air will not bring it back. How to tell if wine has gone bad has the wider checklist. Cork taint is a separate fault with no bubbles at all; how to tell if wine is corked covers its test.

Why Is My Red Wine Fizzy?

A fizzy dry red has three usual suspects. Wine Spectator says it can be "only a temporary setback, usually caused by some extra carbon dioxide." VinePair blames yeast in a wine "bottled too young, or with too much residual sugar." Or malolactic bacteria finish under the cork. Clear and fresh means gas; haze or a sour-milk note means a fault.

Malolactic fermentation (MLF) is the bacterial step that turns sharp malic acid into softer lactic acid, releasing carbon dioxide. Most reds go through it on purpose in the cellar, where the gas escapes. Bottle a red with malic acid left and a few bacteria alive, and it can finish in the bottle. Vinmetrica, a winery lab supplier, warns that stragglers of Oenococcus oeni could "wake up to a nice malic acid breakfast and start making CO2 in your bottle."

The AWRI lists the result as dissolved carbon dioxide, haze and sediment. That is how a bone-dry red can fizz: no sugar for yeast, but malic acid for bacteria. The typical clue is a creamy or sour-milk smell in a red that should smell of fresh plum or cherry. What is malolactic fermentation covers MLF when it goes to plan.

What Is Refermentation, Exactly?

Refermentation is alcoholic fermentation starting again after bottling. WineMaker Magazine's Wine Wizard column names the two ingredients: a re-ferment "can happen anytime there are yeast present and there is still fermentable sugar present in the wine." The sealed bottle traps the carbon dioxide. Wine yeast and fermentation covers what yeast does in the first place.

Very few cells are needed. The AWRI warns that "even a small number of cells in a bottle can referment, causing cloudiness and eventually sediment," along with a yeasty aroma. The smell is usually close to bread dough or beer.

Residual sugar sets the risk. The same column says most wineries treat under 0.3% residual sugar as dry, which leaves yeast almost nothing to eat. So if a bone-dry wine fizzes, suspect bacteria or leftover gas. Off-dry and sweet wines carry sugar on purpose (tasting residual sugar in wine shows how much), and above 10 g/L the AWRI's explosion warning applies. If a sweet wine fizzes and its cork has risen, open it with the care described above.

Which Wines Are Supposed to Fizz?

Pét-nat, Vinho Verde and Italian frizzante are bottled with gas on purpose, and for them bubbles, haze and even sediment are features. Their labels name the fizz, so a label that says nothing about bubbles belongs to a wine that was meant to be still.

Pét-nat (pétillant-naturel) is bottled before its first fermentation finishes. The last sugar becomes bubbles under a crown cap, and the yeast often stays in as haze. It is refermentation by design, in a bottle built for it; the pét-nat guide says what to expect. Vinho Verde is often bottled with a light spritz (Vinho Verde region guide). Italian frizzante wines, such as many Lambrusco bottlings, sit in the 1 to 2.5 bar semi-sparkling class.

How Do Wineries Prevent Refermentation?

Wineries remove one of the ingredients before bottling: the sugar, the malic acid or the organisms. Most use several steps at once, because a few surviving cells are enough to restart fermentation. Off-dry and sweet wines need the most protection, since they keep sugar on purpose.

• Ferment to dryness, so yeast have nothing left to eat.
• Finish or block MLF, so no malic acid is left for bacteria.
• Sulfur dioxide (SO2), wine's standard preservative. The Wine Wizard column suggests 28 to 35 ppm free SO2 to keep most bacteria in check. The AWRI cites 0.8 mg/L molecular SO2 against spoilage microbes. See sulfites in wine.
• Sterile filtration at bottling, which the AWRI calls the best defence against Zygosaccharomyces, a hardy spoilage yeast. Vinmetrica uses a 0.4 micron filter to catch bacterial stragglers.

Low-intervention wines often skip filtration and keep sulfur low, so refermentation is more likely in them. Natural wine explained sets out that trade-off. If a natural wine is hazy and lightly fizzy, ask the shop whether that bottle is meant to be that way.

Should You Return a Fizzy Bottle?

Return it when the fizz comes with haze, sediment, an off smell or a pushed cork in a wine sold as still. Keep it when the prickle stands alone in a clear, fresh-smelling glass. In a restaurant, VinePair notes, you can "easily just send the bottle back." Shops usually replace a refermented bottle when told what was wrong.

Run these checks before you decide:

1. Read the label. Pét-nat, frizzante, Vinho Verde, "col fondo" or any sparkling category means the fizz is intended.
2. Hold the glass against something white. Haze all the way through, plus bubbles, is the strongest single sign of a fault.
3. Smell it. Bread dough or beer points to yeast, sour milk to bacteria, and fresh fruit to a sound wine.
4. Check the cork. A risen cork, sticky capsule or weeping seal means pressure or heat, and either justifies a return.
5. Wait ten minutes. If the wine passed all four, swirl it. A style prickle softens with air and time.

After a glass, stop if it tastes wrong and take the rest back. When to send wine back covers how to raise it at the table, and wine flaws vs faults draws the line between a quirk and a flaw. The wine faults hub collects every fault guide. Sommy walks through look, smell and taste when you photograph a label, and logs the notes to a tasting journal.

Sources

1. WineMaker Magazine — Wine Wizard: Refermentation and Malo on the Move
2. Australian Wine Research Institute — Microbiological Hazes and Deposits
3. VinePair: Why Is My Still Red Wine Actually a Bit Bubbly?
4. Wine Spectator — Dr. Vinny: Is Fizziness a Flaw in a Still Red Wine?
5. Vinmetrica — Malolactic Fermentation Tips and Tricks
6. Regulation (EU) No 1308/2013, Annex VII Part II: Categories of Grapevine Products