When you tilt a cup of espresso for that last sip, it shouldn\u2019t come as a surprise to spy some tiny sugar crystals stuck to the bottom. It\u2019s not cause for concern and simply means you didn\u2019t stir long enough to dissolve the sugar you added.\r\n\r\nBut a minor alarm often goes off when a similar scenario unfolds in a glass of wine. When tiny white or red crystals, or a dark, reddish sludge appears from an almost-empty glass, it\u2019s time to rinse and refill.\r\n\r\n\r\nWhat is wine sediment and is it dangerous?\r\nIs sediment in red wine really a cause for concern? Are crystals in white wine dangerous? Is it safe to drink wine with dregs of various sorts in the bottom?\r\n\r\nThe answers to these questions? No, no, and yes. Kind of.\r\n\r\nAlmost always, when sediment, dregs or the little crystals also known as \u201cwine diamonds\u201d appear in the bottom of a glass, they present no danger. It\u2019s often a sign that the wine was made with minimal intervention.\r\n\r\nWhen sediment, dregs or the little crystals also known as \u201cwine diamonds\u201d appear in the bottom of a glass, they present no danger.\r\n\r\nMost of the time, sediment in wine is either tartrate crystals (\u201cwine diamonds\u201d) or spent yeast, called lees, which are both natural byproducts. Neither is harmful to your body.\r\n\r\nBut if you don\u2019t see the sediment before it\u2019s on your tongue, you might gag on this gunky little surprise.\r\n\r\nTo get rid of sediment quickly, pour wine into a decanter or any good-sized pitcher, through a fine-meshed sieve, a few layers of cheesecloth or a paper coffee filter. It\u2019s smart to rinse the coffee filter first with hot water.\r\n\r\n\r\nNatural tartrate crystals\r\nTartrate crystals are bits of potassium bitartrate or calcium bitartrate that have fallen out of solution in the wine. They\u2019re more common in white wine and usually happen when wine has been refrigerated for a long time. If you remember from chemistry class, heat can help solid substances dissolve in fluids, while cold can force them back into crystal form.\r\n\r\nPotassium and tartaric acid are two natural components of grape juice. They link up and remain in wine after fermentation, when yeast turns the grape sugars into alcohol and carbon dioxide. Most of the world\u2019s commercial wineries prevent this through cold stabilization, a process that causes the tartrate crystals to precipitate out of the solution before being bottled.\r\n\r\nOne technique involves chilling the wine below 32\u00b0F for up to three weeks via temperature-controlled tanks or cold rooms. Afterwards, the potassium bitartrate crystals left in the tank can be gathered, finely ground and sold as \u201ccream of tartar.\u201d\r\n\r\nLabs and companies have devised other methods of tartrate stabilization. One employs mannoproteins extracted from the cell walls of yeast. This came from the observation that wines aged on the lees, which are the sediment of mostly dead yeast cells left after fermentation, are less likely to develop tartrate crystals after bottling. Another method, electrodialysis, passes the wine against an electrically charged membrane in a sophisticated filtration unit.\r\n\r\n\r\nRed wine means lees sediment\r\nMany wineries stabilize their white and ros\u00e9 wines, but not their reds. There are two reasons for this.\r\n\r\nMost high-quality red wines are aged on their lees for at least a few weeks. Thus, they\u2019re less likely to shed their tartrates later. White wines, though, are aged on their lees less often.\r\n\r\nSecond, most popular red wines don\u2019t need to be chilled to taste their best. This means they\u2019re less likely to be refrigerated and form tartrate crystals in the bottle.\r\n\r\nBut the other form of sediment, lees or dregs, is almost always a red-wine phenomenon. More specifically, it\u2019s a phenomenon in well-aged red wines.\r\n\r\nTypes of Wine Sediment\r\nWhite wine: Tartrate crystals, or "wine diamonds"\r\nRed Wine: Lees, or spent yeast\r\n\r\nWinemakers use whole crushed grapes\u2014the skin, juice, seeds and pulp\u2014to make red wine. Only the juice and pulp are used to make white wines. Red wine gets most all of its color and much of its aroma, flavor and texture from the skins. Because of this, red wine has more grape particles suspended or dissolved in it.\r\n\r\nA new wine is full of skins, seeds and bits of stems, as well as used-up yeast cells from the fermentation process. A portion of these stay in the wine.\r\n\r\nA lot of that debris falls out while the wine ferments and ages. Then, when the winemaker pumps, or \u201cracks,\u201d the wine, those lees stay behind and are removed. But microscopic solids remain, even after the wine is pressed, aged for months and filtered.\r\n\r\nAfter many months or years in bottle, some of that stuff will form a fine silt or sediment of lees at the bottom. This happens in almost every good, ageworthy and tannic red wine, whether Bordeaux, Barolo, Rioja or California Cabernet Sauvignon. The fine sediment can form a visible lengthwise strip if a bottle lays on its side undisturbed for years or decades.\r\n\r\n\r\nCan you decant?\r\nThe lees won\u2019t hurt anyone, but few people really want to drink them. Luckily, decanting was invented for just this purpose.\r\n\r\nThe idea is to pour the wine off the lees slowly, so they stay in the bottle. A flashlight can help with this. If you place a light under the bottle as you decant, you can see when the sediment starts to move into the neck. That\u2019s when you stop pouring.\r\n\r\nBefore you decant, it\u2019s critical to get all of the lees collected onto the bottom of the bottle. If the wine has rested on its side, stand the bottle upright for a few days before decanting.\r\n\r\nBut remember, this is not rocket science or a master sommelier exam. If there\u2019s no time to wait, or if you fumble the decanting, just pour the wine into your guests\u2019 glasses. When they get to the bottom and wonder how sediment got into their wine, you\u2019ll know what to tell them.