Tuesday, January 12, 2010

Wine diamonds.

This is what happens in a bottle of wine if cold stabilisation has NOT taken place. It is not essential for wine to be cold stabilised, as evidenced by the underside of the cork in the photograph above (from a bottle of Chenin blanc), but it does make it more palatable to the consumer.
Crunchy wine, anyone?


Wartime Housewife said...

Forgive my ignorance, but is cold stabilisation a fast, industrial way of fining? Does it then have to undergo more filtering or syphoning to leave the sludge behind? Ergo,if one is making wines or liquors on a domestic scale, will they fine more quickly in a cold environment? Answers on 4 sides of A4!

Do Bianchi said...

Tracie B and I found diamonds in a wonderful bottle of Lapierre Morgon we drank the other night.

But alas, these diamonds are not everyone's best friend! ;-)

Vinogirl said...

WH: Two different processes, but in this case, performed simultaneously to minimise handling the white wine too much. Tartaric acid is the main, and unique, acid in grapes and wines, the concentration of which becomes supersaturated as fermentation proceeds. The deposition of potassium bitartrate in the bottle is considered to be an aesthetic defect and so steps are taken to stabilise the wine prior to bottling. The cold temps, for 2-3 weeks do indeed aid potassium bitartrate stabilisation.
Fining is the process that removes impurities in wine; proteins, polyphenols, pectin etc. The wine is then filtered prior to bottling (in this case to also remove the ML bacteria), but this process is not always performed as you can buy unfiltered (and unfined) wines out in the market place. Many small producers do not have the means to perform some (or all) of these winery operations and so you sometimes find cream of tartar in your glass, hence wine diamonds.
(Wine can also be heat stabilised.)

Do Bianchi: While I would much prefer the friendly diamonds immortalised in song by Ms. Monroe, the presence of diamonds in my glass is of no big importance. That is until you knock back the last sip in your glass and find your mouth full of grit...it's not an experience for everyone!

Wartime Housewife said...

Blimey - that's cleared that up! One more question. Why do I need to add tartaric or citric acid to elderflower cordial?

Vinogirl said...

Cordial? Like Quash orange drink in the 70s?
Most beverages benefit from a certain degree of acidity, it improves the mouth feel, makes you salivate a little bit that in turn makes you want to drink more.
If your cordial is going to be alcoholic I would recommend tartaric acid, if not just use citric acid (because citric acid can be converted to vinegary acetic acid during fermentation.)

Wartime Housewife said...

That's brilliant Vinogirl, thank you. I'd forgotten about Quosh - it had a very odd bottle. Oh no, that was Treetop!

I make elderflower cordial and sometimes blackberry or any other fruits which happen to be around and the old recipes suggested tartaric acid but it's quite hard to get hold of. Now I use citric which works just as well but I didn't know why I had to use it at all. I'd assumed it was a preservative.

Now could you just quickly explain the first law of thermodynamics?

Vinogirl said...

Well acid can act as a preservative. High acid wine (low pH) creates a more inhospitable enviroment for microbes...but also adds to our enjoyment, a flabby wine just dies on the palate.

Quash did have a weird big cap I believe.

Can't help you on the thermodynamics...except to suggest picking up an extra log and throwing it on the fire to keep yourself warm in chilly Blighty.