Are wine crystals the same as sediment?

No. Wine crystals are potassium bitartrate, formed when the wine's natural potassium and tartaric acid drop out of solution, often after cold storage. They have edges and facets, look clear in whites and dark red in reds, and often cling to the underside of the cork. Red wine sediment is pigment and tannin that bonded together as the wine aged, and looks more like silt or flakes. The AWRI says tartrates pose no health risks if consumed.

Is it safe to drink red wine with sediment in it?

Ordinary sediment in an older red is safe to drink; Wine Spectator calls it perfectly safe, though it can taste bitter and feel gritty. To avoid it, stand the bottle upright for 24 hours or more, then pour slowly over a light and stop when the deposit reaches the neck. If anything looks like glass, or the wine smells of vinegar or mould, do not drink it; take it back to the retailer.

Do bits of cork in wine mean it is corked?

No. Floating cork crumbs only mean the stopper broke up when it was pulled, and they can be lifted out with a spoon or caught in a strainer. Corked wine is a smell problem, usually caused by a compound called TCA, which the Australian Wine Research Institute describes as having a distinct musty, mouldy aroma that suppresses fruit. A corked wine can have a perfectly intact cork.

Why does white wine get crystals in the fridge?

Cold lowers how much potassium bitartrate a wine can keep dissolved. AWRI solubility data for a 14% alcohol solution show 2.51 g/L at 20°C but only 1.24 g/L at 5°C, so a long spell in the fridge can push the excess out as small clear crystals. They are harmless and do not change the flavour; pour gently and leave them behind in the bottle.

Serving & Storage

What Is Wine Sediment? Crystals, Deposits and Cork Bits

Tiedemann on Wines · 2026-10-15 · 7 min read

In briefWine sediment is solid material that settles out of wine in the bottle. In older reds it is mostly colour pigments and tannins that have bonded and dropped out; in any wine it can also be tartrate crystals (potassium bitartrate, the compound in cream of tartar) or spent yeast called lees. These affect texture, not safety, so stand the bottle upright and pour gently. Anything that looks like glass, or haze with an off-smell, is a reason not to drink the wine and to return it.

Contents

What is wine sediment?
Why is there sediment in red wine?
Is sediment in red wine safe to drink?
Wine crystals vs sediment: how do you tell them apart?
Do bits of cork mean the wine is corked?
What if the wine is hazy or something looks wrong?
How do you separate wine from sediment gently?
Can you stop crystals or sediment forming?
Sources

What is wine sediment?

Wine sediment is solid material that settles out of a wine in the bottle. In older red wines it is mostly colour pigments and tannins that have bonded together and dropped out of the liquid. In any wine it can also be tartrate crystals (potassium bitartrate, the same compound sold as cream of tartar) or lees (spent yeast left from fermentation). These common deposits change the look and texture of a glass, not its safety. Something that looks like glass, or a cloudy wine that smells wrong, is a different matter, covered further down.

It is also one of the most common reasons people query a bottle. In a column for winemakers, the Australian Wine Research Institute (AWRI) reports that hazes and deposits in packaged wine "consistently make up around 40% of investigations" handled by its helpdesk, and that the majority "are protein, tartrate crystals and wine yeast/bacteria."

Why is there sediment in red wine?

Time, mostly. Wine Spectator's decanting guide explains that older red wines and Vintage Ports naturally produce sediment as they age, while white wines rarely do, because "the color pigments and tannins bond together and fall out of solution." The same guide says it is fairly safe to assume a red will have accumulated sediment after five to 10 years in the bottle. The deeper, more structured reds in our guide to red varietals are the usual candidates, since they start with more of the tannin and pigment that later drops out.

Winemaking choices matter too. Many wines are fined and filtered before bottling to remove solids. The Quebec liquor board's SAQ guide to sediment notes that wines that have not undergone filtration or fining "will obviously contain more solids, and thus, more deposits," and that older wines, or those labelled "non-filtered," can safely be assumed to "contain some sediment."

Where the sediment ends up depends on storage. A Wine Spectator answer on whether sediment is harmful points out that it can collect on the side or the bottom of the bottle depending on how the wine was kept, and that a bottle stored for a long time in one position can have sediment stuck to the side.

Is sediment in red wine safe to drink?

The ordinary pigment-and-tannin kind is. That same Wine Spectator answer calls sediment in an older red "perfectly safe to drink," while adding that it is "pretty unpleasant and can have a bitter taste." The decanting guide notes that stirring it up as you pour clouds the wine and can add bitter flavours and a gritty texture. The reason to keep it out of the glass is pleasure, not protection.

Wine crystals vs sediment: how do you tell them apart?

Tartrate crystals are a separate thing from aged red sediment. The AWRI column explains that grape juice naturally contains both potassium and tartaric acid, which pair up as potassium bitartrate; when a wine holds more of it than the alcohol-and-water solution can keep dissolved, it "drops out of solution as crystals." In white wine they "might look like small glass shards." In red wine they are usually dark red "and could be mistaken for residual colour, tannin or even pieces of oak/wood."

Cold drives it. The AWRI's page on potassium bitartrate instability reproduces solubility data (Berg and Keefer, 1958) for alcohol-water solutions: at 14% alcohol, 2.51 g/L dissolves at 20°C but only 1.24 g/L at 5°C, roughly half. That is why crystals often appear after a long spell in the fridge. The same page describes deposits ranging from just a few crystals adhering to the cork to several grams at the bottom of a bottle. Wine Spectator adds that they are usually found clinging to the bottom of the cork, are safe to consume and do not affect the wine's flavour.

The AWRI column goes further: tartrates are non-toxic and non-allergenic, are used as food additives such as cream of tartar, and "pose no health risks if consumed."

A quick way to read what you are looking at:

What you see	Likely identity	Where it usually sits	What to do
Clear or white crystals in a white or rosé; dark red crystals in a red	Tartrate crystals	Underside of the cork, or the bottom of the bottle	Pour gently and leave them behind
Dark, fine, silty or flaky deposit in an older red	Pigment and tannin sediment	Bottom, or along one side if stored lying down	Stand the bottle upright, then pour off the clear wine
Fine, pale cloud that swirls up when the bottle moves	Lees (yeast) in an unfiltered wine	Settled at the bottom until disturbed	Let it settle, or accept it as part of the style
Light brown, spongy crumbs floating at the surface	Pieces of the cork	Floating in the neck or the glass	Lift out with a spoon or pour through a strainer

Colour alone is not a reliable test in red wine, since crystals and sediment can both be dark red. Shape is the better clue: crystals have edges and facets; sediment looks like silt or flakes.

Do bits of cork mean the wine is corked?

No. Crumbs of cork in the wine mean the stopper broke up on the way out. "Corked" describes something you smell, not something you see: cork taint, usually caused by a compound called TCA (2,4,6-trichloroanisole). The AWRI's guide to wine faults describes TCA as having "a distinct musty, mouldy aroma" and notes that it suppresses positive fruit-derived characters. A wine with cork crumbs and a clean, fruity smell is fine to strain and serve; a wine with a musty, mouldy smell may be corked whether or not any cork is floating in it, and is worth taking back to the shop.

What if the wine is hazy or something looks wrong?

Some haze has a harmless explanation. The AWRI column explains that grape proteins can survive winemaking and cloud a finished wine, particularly a white, and that while such a protein haze "may not look attractive, it poses no risks to human health." The same column notes that natural wines, and deliberately unfiltered and unfined wines, often contain residual yeast lees to aid texture.

The difficulty is that a reader cannot tell one haze from another by eye, and this article cannot diagnose a bottle. The following are reasons not to drink a wine and to take it back to the shop or contact the producer instead:

Anything that looks like glass and does not match the crystals described above, or a chipped bottle neck or rim. Do not taste the wine to find out. Keep the bottle and the fragment for the retailer.
A still wine that fizzes or pushes against the cork when opened.
A cork that has pushed partly out, or a capsule that is sticky or leaking.
Haze that comes with a strong off-smell. The AWRI faults guide lists volatile acidity as "generally perceived as the odour of vinegar," along with descriptors such as nail-polish remover for ethyl acetate.

Sediment in an old red and crystals on a cork are normal. Anything outside those descriptions is a question for the retailer.

How do you separate wine from sediment gently?

The method is patience, light and a steady hand. The steps below follow Wine Spectator's decanting guide unless noted.

Stand the bottle upright for 24 hours or more before opening, so the sediment can slide to the bottom. The SAQ suggests letting the bottle rest vertically "for a few hours, or even a few days" for older wines.
Remove the capsule and cork and wipe the neck clean, leaving the bottle standing.
Put a light under the neck. A candle or a torch works, so you can watch the wine pass through the shoulder.
Pour slowly and steadily into a decanter or clean jug, without stopping, and more slowly still through the bottom half of the bottle.
Stop as soon as sediment reaches the neck, or if the wine turns cloudy or you see what look like specks of dust.
Discard the last ounce or two of sediment-filled wine in the bottle.

On short notice, a fine-mesh tea strainer or a rinsed, unbleached coffee filter in a funnel catches most crystals, cork crumbs and coarse sediment; that is our own suggestion, not a step from the guides above. For crystals alone, pouring gently and leaving the last centimetre in the bottle is usually enough.

Once poured off, the clear wine behaves like any opened bottle; how long it keeps depends on its style.

Can you stop crystals or sediment forming?

Not entirely, and there is no need to. Sediment in an aged red is a by-product of the slow changes people age red wine for. Crystals are more likely after long, cold storage, so a white chilled for an evening rather than a month is less likely to throw them; the serving temperature guide covers how cold is cold enough.