Wine sediment: what you need to know

Why does wine sediment form? 

Often, the wine sediment appears in the form of crystals, which are sometimes called tartar.

Have you ever noticed small crystals or particles in your glass? Of course, it would help if you were not afraid of them. However, they are entirely safe for health and do not affect the taste of the drink in any way. So let’s try to figure it out.

The wine sediment is crystals of the salt of tartaric acid, the essential acid found in wine. In the language of chemistry, they are called potassium and calcium bitartrates. They appear naturally in wine and can precipitate over time.

Wine sediment
Sediment in the wine bottle

Although crystals are perfectly safe, many consumers are confused, so producers often cold stabilize before bottling wine. To understand what it is, it is worth recalling chemistry and physics a little: high temperatures increase solids’ solubility in liquids, and low temperatures, on the contrary.

Winemakers use this principle by chilling the wine before bottling, causing the salts to precipitate and thus minimizing the risk of wine sediment in the bottle. Unfortunately, this procedure is quite costly: the wine must be kept at temperatures below 32 F (0 ° C) for two to three weeks, dramatically increasing electricity costs.

Wine sediment – types of sediment


Some wineries use a method called electrodialysis. The collected (wine sediment) crystals are not thrown away but used to produce tartaric acid or the so-called “tartar,” food production, cooking, and pharmaceuticals. Also, metatartaric acid, mannoproteins, and carboxymethyl cellulose are used to suppress tartrates (the names are scary but not harmful to health).

Wine sediment
Tartaric Acid – Wine Diamonds

Cold stabilization is usually done for white and rosé wines, but not for reds. The fact is that red wines are often aged after fermentation on yeast sediment, which binds tartrates. In addition, red wines usually mature longer, so there is time for the formation and precipitation of bitartrates.

Phenolic compounds

In red wines, especially aged ones, you can find another type of wine sediment – particles of red-brown color. In producing red wines, grape juice is used for traditional whites and the skin and seeds. Respectively, red wines contain much more microparticles. This is because yeast cells are added to them after fermentation.

During aging, a lot of wine sediment settles to the bottom of the containers in which the wine is stored. To remove sediment, winemakers regularly carry out suction or removal from the deposit. But some of the residues remain in the wine after.

Wine sediment
During aging, a lot of wine sediment settles to the bottom

The so-called phenolic compounds pass from the skin and seeds into the wine: anthocyanins, which give the wine its color, and tannins, which are responsible for the astringent sensations in the mouth, which over time form polymer chains that can also precipitate.

The sediment in the wine enhances the taste of the wine

Many producers choose not to filter the wine before bottling to preserve its flavor and aroma characteristics to the maximum and prolong the aging potential. Don’t be alarmed if you find sediment in a bottle of good old wine from Bordeaux, Rioja, or Barolo. It just means that the winemaker didn’t filter the wine too hard.

Causes of clouding wine

This phenomenon is most often associated with production errors, and most experts will call such a wine defective. Particles suspended in wine can be the result of yeast and bacteria. Wines with residual sugar that have not passed sterilizing filtration are at greater risk. We did not receive a sufficient dose of sulfites to deactivate microbiological processes. In such wines, under the influence of microorganisms, re-fermentation may start, turbidity or wine sediment may appear.

Red Wines
Re-fermentation may begin in wines

Another type of defect occurs mainly in white wines. It is called “protein haze.” Grapes contain a small amount of protein. If they are not removed during production, the same “protein sediment” may appear in the wine. To cope with this problem, which does not pose a threat to the consumer’s health, but significantly spoils the appearance of the wine. Manufacturers use bentonite, a natural substance that binds proteins and causes them to wine sediment, which can easily remove.

Decantation – wine sediment filter

The problem of sediment has become a concern of consumers only recently. For centuries, it was a common thing and did not raise questions. Today, producers take on most of the responsibility, reducing the risk of sediment precipitation already in the production process. However, there are still types of wine in which it is almost inevitable: mainly red wines with long aging and vintage ports, which are deliberately bottled without filtration.

Red Wines
Decantation is a process that is necessary to separate the wine from the sediment and saturate it with oxygen

If you come across such a bottle, it is a great joy! You can practice decanting like a real sommelier. To effectively eliminate the wine sediment, the wine must be carefully poured into a clean jug or a particular decanter without shaking, leaving the residue inside the bottle. To achieve the perfect result, you can use a light source (candle or phone flashlight) to shine through the bottle and stop the overflow in time, preventing sediment from seeping into the decanter. If the residue is mixed with the wine, you can strain the drink through a fine sieve or muslin cloth.

If you don’t have the time and desire to carry out all these manipulations, it’s okay: in most cases, the wine sediment does not pose any danger to health and only affects the aesthetics of consumption.

Drink Like a Pro – All About Decanting


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