Thursday, May 28, 2009

Cold stabilisation.

Cold stabilisation is an important step in the process of winemaking. It is the means by which the excess tartaric acid in wine is precipitated out as potassium-bitartrate salt. Tartaric acid is very soluble in wine, it's less soluble mono-salt, potassium-bitartrate preciptates out in an effect known as 'salting-out'. This lowers the total acidity, and alters the final pH, of the wine.
Now some people may like wine diamonds in their glass, but most consumers prefer a little less crunch in their wine beverage of choice. The purpose of potassium-bitartrate stabilisation is to prevent the crystallisation of the tartrate in the bottle.
This is a 3 week long operation at the winery with the tanks being frozen down to 27F, resulting in a good half inch of ice on the outside of the stainless steel. Additions, in ppm, of isinglass and bentonite aid in the fining process which produce a beautifully clear wine that is however still rich in ML bacteria...on to the filter.
On a 90F day, like it was yesterday, I try to find any excuse to be in the tank room so that I can give a frozen tank a hug...even if it does contain Chardonnay!

12 comments:

Weston said...

now is that because you don't like the chardonnay Vine? or the wine...because I'm not the biggest fan of chardonnay wine *shrug*

Vinogirl said...

That would be Chardonnay the wine. It's not the poor grapes fault. Overly oaked and overly manipulated in California. There are so many other white wines that I would rather drink.
Did anyone say Viognier?

Weston said...

Funny Viognier is probably one of my favourites grapes. As long as it isn't oaked people and there over oaking. I just love floral noses and the structure of it going with a lamb dinner good ole Coindreau

Only Chardonnay I like is Blanc de Blanc Champagne

The villager: said...

I like the image of ninety degrees outside and hugging a frozen tank.

Do you have any problems with water supply (rain) over there ?

Thud said...

As a visiting Brit I like the fact that for 9 months it doesn't rain...but then I'm not a farmer!

Vinogirl said...

Weston: Bubbly...Pinot noir based for me I'm afraid.

Villager: Yes, water a problem. In our second drought year and people are a bit worried.

Thud: Steady on, it's usually only 8 months. Rain forcast for next Wednesday, very unseasonal.

Therese-A-Saurus said...

Hi, I noticed you stopped by my blog and left comments.
I started my Vinogirl blog in 2007 and didn't realize there was another Vinogirl out there. I'm sure we aren't the only Vinogirls online. There's enough wine to go around in this world.

If you read my blog you would notice that my wine blog is fun and not meant to be a pretentious, technical wine blog. I write for the every day wine drinker. I am a native northern California and am a big fan of wine.

Vinogirl said...

Hi Therese, I am sure there are a million vinogirls, and women, out there.
Thanks for stopping by Vinsanity.

Craig Justice said...

This why I appreciate white wine and this is why I don't make it! However, we made a blush wine from a field blend of our red grapes last year: picked, pressed and ended up with a wonderful rose color juice. Added the yeast -- there was no cap to punch down -- but essentially I treated it like a red fermentation. Fermented to total dryness. Racked a couple of times (OK, this was a small batch, so easy to rack.) And it came out beautiful, and wonderful to drink on hot days (which we had last weekend). No refridgeration. No cold stabilization. Done in the garage. Easy as pie. (I think one of the keys was no residual sugar.) Beginner's luck? What do the experts say?

Thud said...

I quite like this pretentious and technical blog...but then some of us look for a little more in life.

Vinogirl said...

Craig: I think you may have experienced beginners luck! I think Vinomaker may have a comment for you.

Thud: You know me, I'm an every day wine drinker!

Vinomaker said...

The main differece between using a red winemaking process for a white or blush wine is air contact. With reds, air, specifically oxygen, is essential in forming compounds that otherwise may become reductive. With whites, air can accelerate oxidation resulting in an off aroma and taste. Even with careful air contact management, different yeasts, lees protocol and cooler fermentation temperatures in the 50F range can assist in retaining the fruity esters of a particular grape variety. Certainly less attention to these details does not mean you will not produce a wine that is drinkable, but you may be giving up some of the qualities that would enhance it.