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ChangeMe
Grape Truck Driver
Posts:44
 | | 01/23/2006 12:08 AM |
| wine stone - Collaborative International Dictionary of English v.0.48 :
Tartar \Tar"tar\, n. [F. tartre (cf. Pr. tartari, Sp., Pg., &
It. tartaro, LL. tartarum, LGr. ?); perhaps of Arabic
origin.]
1. (Chem.) A reddish crust or sediment in wine casks,
consisting essentially of crude cream of tartar, and used
in marking pure cream of tartar, tartaric acid, potassium
carbonate, black flux, etc., and, in dyeing, as a mordant
for woolen goods; -- called also argol, wine stone,
etc.
Webster] | | | |
| WineJedi
Grape Sorter
Posts:351
| | 01/23/2006 1:31 AM |
| great information in this thread but i have a question. does this occur only in white wine or reds also?  | | | |
| ChangeMe
Grape Picker
Posts:3
| | 02/02/2006 11:50 PM |
| Quote:
great information in this thread but i have a question. does this occur only in white wine or reds also?
Newbie here... To answer your question, yes there is precipitation is reds, too, though I don't think it's the same stuff that precipitates in whites. My understanding is that in reds the precipitation is a bi-product of the tannins, and again, it's nothing to be concerned about, though it's best to avoid getting the gritty stuff in your glass (hence, older wines are sometimes decanted and/or strained before serving). Is the tannins part correct? | | | |
| Dave Tong
Santa Clara, CA
Barrel Filler
Posts:1331
| | 02/08/2006 2:38 AM |
| Quote:
I really don't see it that often myself but when it happens it doesn't bother me in the least. Just pop and pour. BTW, for some reason, I mostly see it on the bottoom of the cork after it is removed. I usually don't see that much in the bottle itself for some reason. I'm guessing since it is laying on its' side it is sticking to the bottom of the cork because it's easier to form there for some reason, correct good people?
The reason that you'll typically see crystals forming on the corks is because when wineries bottle the wines they are initially stored inverted. The initial process of crystal formation is called nucleation. The presence of the rough cork surface may assist in the nucleation, in the same way that an impurity or rough spot in a champagne glass tends to assist the formation of bubbles.
Eventually the crystal becomes too heavy to remain in solution and is precipitated out. Once this initial solid crystal has formed it will attract other similar molecules and grow. You may have grown salt crystals as a kid, or maybe your kids have.
If the crystal didn't form on the cork initially it will sink to the bottom and land on the cork. Then, as it grows it will naturally spread into the porous surface and thus attatch itself more strongly. If the wine is then inverted (right side up) the crystals will remain attached to the cork. then, when the wine is laid down the crystals will resume forming on the cork due to the inter-molecular attraction. It's easier to join an existing crystal than to form a new one. | |
http://scmwine.blogspot.com - My wine blog.
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| Dave Tong
Santa Clara, CA
Barrel Filler
Posts:1331
| | 02/08/2006 2:46 AM |
| Quote:
great information in this thread but i have a question. does this occur only in white wine or reds also?
You can get crystals in red wines. The crystals are potassium tartrate. Grapes naturally contain tartaric acid and small amounts of potassium. They precipitate out at low temperatures. Typically white wines are stored at lower temperatures than reds which assists in the formation of the crystals. | |
http://scmwine.blogspot.com - My wine blog.
http://scmwine.wikispaces.com - your guide to the Santa Cruz Mountains and Santa Clara Valley
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| Joseph Filippi
Grape Picker
Posts:22
| | 05/07/2006 5:02 AM |
| yes the "stuff" on the bottom is most likely tartrates, the wine was not cold stableized enough or not at all. Cold stableization is simply fining the wine with some gelatin, not much maybe 1/8 pound per 1000 gallons at the most, then seeding the wine, droping the temperature to say 30 to 50 deg. F to help coagulate the crystals. Then the wine is filtered while cold, then it is tested again in a lab. The wine could also have a protein problem from not being heat stableized. This is accmplished at the same time as cold stableization in some wineries to save time and expense by adding Bentonite (volcanic clay) to the wine and after mixing the Bentonite "latches" on to the proteins and being that it is clay, it drops everything in the wine to the bottom. Then filtered out.
Joe | | | |
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