Editor’s Note: Carl is still recovering and is not back to writing full-time, but he did have this gem tucked away that we are sharing this week.
A wine customer called me the other day and told me he had some bad bottles of Sauvignon Blanc wine. He went on to explain that there were little white “things” on the bottom of the corks. Actually, the “little white things” are Tartrate (Tar-trate) crystals (also called wine diamonds) and are absolutely harmless. You may also find them at the bottom of the wine bottle or sometimes they’ll end up in your wine glass. Personally I have had them show up on the bottom of corks and in my wine glass.
Some people think they are salt, sugar or sediment. The fact is they are harmless…occurring naturally in some wines. When wine is exposed to cold temperatures, below 50 degrees (they can materialize if you store your wines in the refrigerator too long), the tartaric acid found in grapes binds with potassium (also in wine) to form a compound known as “potassium-bitartrate.” It is known as potassium hydrogen tartrare and is a byproduct of winemaking. In cooking it is known as “cream of tartar.” The compound is actually a form of acid salt. In the fermentation process of winemaking the potassium-bitartrate crystallizes and forms the little crystals or diamonds.
White grapes contain fairly large amounts of potassium-bitartrate. If it isn’t removed, the wine will form these little crystals when placed in a refrigerator or chilled below 50 degrees for a longer period of time.
To remove excess potassium-bitartrate before bottling some wineries, not all, place the wine in stainless steel tanks and lower the wine’s temperature to above 30 degrees. The wine stays at that temperature for two to three weeks allowing the crystals to form and settle to the bottom of the tanks. The crystals are then removed by filtration or by pumping the wine from the tank and leaving the crystals in the bottom where they formed.
Higher-end wines are more likely to have tartrates since many of these wines are not filtered in an effort to preserve the nuances and/or complexity of the wine. The crystals are found in both red and white wines. However, they are more typical in white wines.
First: Remember that these tartrate crystals are not harmful. The crystals will have a salty, slightly sour taste. They don’t dissolve very fast and will feel more gritty in your mouth than anything else.
Second: If you encounter these crystals in your wine (normally in the bottom of the bottle). Unless you pour them into your glass with the last bottle pour they shouldn’t be an issue.
If it bothers you to have them in the bottle or you experience some in your glass you can certainly decant the wine through a fine mesh sieve or screen to remove them should they be a nuisance.
Finally, do not store you wines in a refrigerator for long periods of time. Temperatures in refrigerators average between 34 and 40 degrees. If you want or need to store the wine in the refrigerator for three to five days it will not be a problem…just don’t do it for weeks at a time.
As always I appreciate your support of our wine blog and encourage you to share it with family and friends. If you are reading this blog for the first time please consider subscribing while you are on the website. This way you’ll get our reviews and articles in your email. If you care to share your comments on this blog posting or other topics please do so in the comments section below.
Until next week,
Calendar of Events
- April 17th – International Malbec Day
- May 4th – International Sauvignon Blanc Day
- May 9th – National Moscato Day
- May 21st – National Chardonnay Day
- May 25th – National Wine Day
- June 11th – National Rosé Wine Day