The Gritty Truth: Why is there Sediment in my Wine?

Kelsey Chesterfield

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Have you ever poured yourself a nice glass of wine just to notice something gritty or sand-like has suddenly invaded your wine and is now swishing around unpleasantly in your mouth? That would be the wine sediment.

So what is sediment?

Sediment is a byproduct of winemaking that usually settles to the bottom of your glass, and it can form during the fermentation process or while a wine matures in a bottle. Sediment is completely natural and not harmful, with most of it made up of bits of seeds, grape skin, and crystal-like tartrates. Some winemakers fine or filter their wines to remove these solids, while others prefer to leave it, believing it gives the wine more character and complexity. If its presence bothers you, simply decant or aerate the wine before serving.

If you’re an avid wine drinker like the majority of us in our office, or if you receive any of our wine club shipments, you’ve experienced this phenomenon at least a handful of times. If you’ve only recently encountered sediment in your glass, don’t worry, as we stated above, there is nothing wrong with your wine! No matter the amount of sediment, it is a completely natural occurrence in red and white wine, and can actually be a sign that you’ve gotten yourself a high quality bottle! But we’ll get to that.

Technically speaking, sediment is also called “wine dregs” - but before you judge your bottle of wine by this unfortunate double-entendre, sediment can also be referred to as ‘wine crystals’ or ‘wine diamonds’. Sounds a bit better than ‘dregs’, right?

Sediment can come in two forms: tartrate and colloids.

1) Tartrates are the larger ‘crystals’ you may find on the end of a cork or clinging to the sides of the bottle or your wine glass. These jagged, burgundy-colored, diamond-like structures are formed when tartaric acid (a natural element in grapes) binds with potassium while exposed to cold conditions. Under these circumstances they form beautiful crystalline salt formations.

2) Colloids, on the other hand, are the smaller and finer-grained sediment which are made of polysaccharides and protein, or can simply be leftover remnants of grape skins, stems or seeds. And yes, both forms of sediment are harmless!

What are Polysaccharides?

Polysaccharides, for those of us who somehow missed that day of chemistry class, are carbohydrates made up of multiple sugar molecules bonded together. They also contribute to the overall mouthfeel of a wine.

But we’re getting off track.

Although sediment is usually more prevalent in red wines, they can occur in white wines too! Winemakers will sometimes intentionally leave tartaric sediment in the barrel while the wine ages. This is called ‘sur lie’ aging, which translates to ‘on the lees’ and can supplement and intensify flavor in the finished wine. You may also see this term used in some of the tasting notes for wines you’ve received from any of our six wine of the wonth clubs.

Related: How does an oak barrel influence the aging of wine?

Finally, these crystals, diamonds and gritty-goodness can indicate you have a high quality bottle of wine! The best winemakers know that, oftentimes, less is more when it comes to intervening with methods like filtering. When wines are filtered, it not only gets rid of the sediment but it also strips the wine of quality features such as mouthfeel and even palate flavor expression. (See our Wine Glossary for further explanations of wine terms!)

So the next time you see wine sediment settle to the bottom of your glass, rejoice! You could be in for a real treat.