Definition - What does Wine Racking mean?
Racking is the process of moving wine from one vessel to another using gravity with the purpose of removing the sediment and lees. This step is completed to help clarify the wine, prevent negative flavors developing from the lees and sediment, and create a desired flavor profile.
Racking takes place an average of three times during the winemaking process: once during fermentation, once after fermentation and once more after fining. Winemakers can choose to do additional rackings, or they can choose not to rack at all (a process called “sur lie aging”). Either choice will result in a different flavor profile in the wine.
WineFrog explains Wine Racking
Racking was developed in 19th century France. Due to the lack of electricity, the first racking process included elevating a fermentation barrel above a second and opening the drain, located 3/4" from the bottom of the barrel; sediment is usually 1/4" thick, so it remained in the barrel.
This process evolved into siphoning, which requires a “siphoning cane” – a rigid plastic, L-shaped tube. A hose is connected to the cane, which is lowered into the original fermentation vessel. The cane has a diversion cap on the end, which shaped like bowl, preventing liquid or sediment from entering the tube from the bottom. Once the racking cane is in place, siphoning starts and the free end of the hose drains the wine into the 2nd vessel.
Racking takes place each time the wine is transferred from one vessel to another. Each transfer has a specific purpose:
After the first stage of fermentation is complete, 70 – 80% of the sediment/lees have fallen to the bottom of the barrel. These are usually made up of grape lees, which contribute negative flavors to a wine.
Fermentation is completed in the 2nd vessel and the remaining 20 – 30% of the sediment (yeast lees) has fallen. Winemakers must remove that within 2 months so that the dead yeast cells don’t negatively affect the wine. Also during this step, the winemaker can choose to add a fining agent.
After the fining is complete, the wine is racked a third time to remove the sediment.
If the wine has not be fined, the winemaker can choose to rack the wine several more times to clarify the wine. Also, if a wine is aged in oak barrels, the winemaker may choose to rack it after a time to ensure the correct amount of oak flavors are transferred. Wines that are aged in the barrel for a prolonged amount of time may require racking once every 3 - 6 months.
Each racking exposes the wine to oxygen. Beneficial in small amounts, as it helps develop aromas and flavors, over racking can lead to oxidation. Also, each racking increases the risk of exposure to bad microorganisms. Finally, each racking results in the loss of some wine – either due to wine left in the sediment or spillage. Winemakers accommodate by topping off the wine with an older vintage or creating a blend of two varieties.