Racking is the process by which wine is siphoned from one container to another in order to remove it from the sediment (‘lees’). Sediment may be anything from left over grape skins to dead yeast cells.
Whereas some wineries may rack during the middle of secondary fermentation, we tend to rack only when we are ready to bottle. In fact, we rarely ever rack our wines more than once (only time being if there is a problem or in some cases when it is a dessert wine ). We do this as we like to be gentle with our wines and avoid possibly spoiling it through oxidization.
We begin racking after the wine has been ‘sur lees’ anywhere from 3 months to multiple years. Roses take 3 months to age, while any of our reserve Syrahs may take two or three years. However, the average time we age the wine before racking is about a year.
In order to rack we use a “bull dog” racking wand which pushes a gas into the top of the barrel and forces the wine out the bottom. We can adjust how high the bottom inlet level is so that the wine coming off is clean and only the lees are left. (We save lees for a variety of reasons – another post.) The wine is racked to a bottling tank where we blend the wines and bottle from.
Nitrogen, Argon and Carbon Dioxide are three gases used to transfer wine into the container. Donkey and Goat uses Argon to rack as it is gentle with the wine and does not dissolve into the wine.
GAS | NITROGEN | ARGON | CARBON DIOXIDE |
CHEMICAL SYMBOL | N2 | Ar | CO2 |
MOLECULAR WEIGHT | 280134 | 39948 | 4401 |
DENSITY GAS ( kg/M3 @ 15°C & 1 atm ) | 1189 | 1.691 | 1875 |
SPECIFIC GRAVITY | 138 | 153 | 2264 |
SOLUBILITY ( v/v ) | 17 | 38 | 101 |
Learn more at http://www.wineqc.com/papers/inertgas/inertgas.html