White Wines
After we have decided on the final blends of matured and ready to bottle wines, each blend is checked for the quantity of heat-unstable proteins. If such proteins are present then a haze is likely to form in the wine after bottling. The addition of a fining agent called bentonite, a type of clay, is made at the required level to remove these proteins from the wine. This process is called heat-stabilization.
At Chateau Carsin we minimize the amount of fining agents added to the wine. As well as taking out undesirable flavour components these fining agents can also remove some good ones. During the earlier stages of production, our efforts are aimed at limiting such additions.
The wine is then racked, chilled to -2 degrees Celsius, and then kept at this temperature for 10 days in order to remove excess tartaric acid. This process is called cold-stabilization. If this process is not carried out, crystals of salts of tartaric acid may form in the wine after bottling.
The wine is then filtered and brought up to 15 degrees Celsius before bottling. At Carsin we do not have our own bottling equipment and prefer to leave this process to the experts. There are a number of specialized bottling companies in Bordeaux that bring their mobile equipment to the property. The only operations needed prior to bottling are setting up and sterilizing the filters, as well as the bottling and corking machines.
The white wine passes through sterile-grade cellulose filterpads, just before bottling. These pads block the passage of yeast cells. Bottles are filled by an automatic filler and then corked using a vacuum corker that takes the air out of the headspace just before the cork goes in. The bottling equipment is quite sophisticated. We minimize contact between the air and the wine and we carry out the whole operation under sterile conditions.
Each style of wine requires different packaging. The type of bottle and cork used depends on the price of the wine and the length of time the wine is designed to stay in bottle. The bottles are then labelled, placed into cartons, and shipped according to the customer's requirements.
Red Wines
Because of its chemical properties and long ageing, red wine does not need as much preparation prior to bottling as white wine. The tannin content of red wines makes them heat-stable. If the wine has been barrel-aged in a cold cellar then there is every likelihood that the wine is cold-stable. Nevertheless it is perfectly normal for there to be some crystals of pigment or acid in bottled red wine. We keep our red wine at -1 degrees Celsius for at least 8 days to minimize crystal formation in bottle. The bottling procedure is the same as for white wines, except that we do not filter the wine through the same grade of filter pad. The bottling equipment is sterilized as above, but the wine is filtered only to give it a final 'polish' - and to ensure that there are no 'nasties' in the bottle!
Corks
With all the problems which have risen from corked wine bottles, also we have tried to find new closures for wine.
We have used for a few bottlings screw cap closures which have been a little complicated for us due to additional logistical problems. In other words the screw caps have meant additional bottlings since not all our customers have accepted the screw cap as a good closure quality wines. We have also had in several cases some problems of reduction of white wines. Now we try to bottle as much of our wines as the market will accept with "Nomacork" closures which esthetically are very near natural corks.
