What the heck is that?!?

[bein_bein]

Last fall we made some wine out of concord grapes from our back yard. Once the wine was done and cleared we added a tiny bit of raspberry liquor and some vanilla for flavor. After a couple more weeks we bottled. Everything was crystal clear. We have drank 4 bottles and have about 5 left. I went to get some today and noticed a crsystals like structure ( that's the best I can explain it) in the bottom corner of the bottles. It's maybe .250 or smaller in a sort of irregular round shape. And it hard. I can hear it make a slight 'tink' sound when I tip the bottle.... Anybody run into this before?!? It wasn't in the bottles that were previously consumed (that I noticed) so it looks like they have formed in the last 2-3 months?? Any ideas???

 

[St Allie]

my guess would be tartaric acid crystals aka 'wine diamonds'

I have read that they are the sign of a good wine in germany.

Allie

 

[Tom]

Yep Allie got it right. You can get them when you cold stabilize or if you keep it in a cool area

 

[B-well4200]

I had that happen with my muscadine last year. What I gathered was that is tartric acid or "wine crystals" as previously mentioned. The way I understand it is, those crystals actually form from an excess in acid and will make your wine better. I am no expert in the subject so I could be completly off. Anyway, it looks almost like sugar crytals in the bottom of the bottles. My wine still tastes good. I just don't drink the last little bit in the bottles.

 

[surlees]

Chemically they're known as Potassium Bitartrate crystals or commonly called "wine diamonds." They usually participate out of wine that has been exposed to temperatures of about 40F or less. They are harmless and can be filtered or decanted out of your wine prior to drinking if you want. They are no reflection on wine quality and the very best wines can have this happen if the wine is not "cold stabilized."

Cold stabilization is often practiced by winemakers to purposely precipitate wine diamonds prior to bottling. At anytime during aging place your carboy in a cold (25F-40F) place for a couple of weeks. This can be a refrigerator or exterior room depending on the climate and time of year. Don't let the wine go below about 25F because it will freeze and may burst your carboy.

Fred