The Science of Wine Racking – Answering the Whys and Hows

Most people use the word “racking” to refer to the racks wine bottles rest upon in a custom wine cellar. But technically, the term “racking” refers to the process of moving wine from one container to another. Proper wine racking is necessary if you want to make quality wine. Learn more about wine racking by reading through this article.

Wine making process

Wine making in California

What is the Purpose of Proper Wine Racking?

Proper wine racking is done primarily to remove wine sediment. Sediment, which is also referred to as lees, consists of dead yeast cells and other particles, such as hydrogen sulfide compounds. Sediment has to be separated from wine, so that the beverage becomes clear. No one enjoys wine with sediment floating in it.

How Often is Wine Racking Done?

Racking wines should be done in a timely manner. Ideally, it should be done at least 3 times throughout the wine making process. Racking can be done more than 3 times if you are bulk-aging your wine.
The following information primarily relates to wine kits. Wine kits do not contain large solids, like pulp, flowers, stems, seeds or leaves. If you are starting from scratch, avoid leaving your wine with these large solids for a prolonged amount of time. Follow these instructions on how to perform wine racking:

1. Primary Racking

For kit wines, the 1st racking should be done on the 6th day of the fermentation process. The 1st racking is primarily done to protect the wine from oxygen, and to remove “gross lees” from it. “Gross lees” refers to the sediment that accumulates during the primary fermentation phase, which comprises about 80% of all the sedimentation that will occur. Some sediment aids in giving flavor and body to wine, but too much will affect its flavor negatively.

During the primary fermentation phase, a large open top bucket with a non-sealing lid is used. The yeasts used produce alcohol and carbon dioxide. The production of carbon dioxide protects your wine from oxygen and other airborne particles. As the fermentation process progresses, the production of CO2 decreases, until there is no longer enough to protect your wine from oxygen. At this point, the racking is done. The wine is then transferred to another container, so that it can be sealed with an airlock, and thus, oxygen and other damaging airborne particles are taken out of your wine.

2. Secondary Racking

Once the fermentation process is complete, the 2nd racking should be done. The length of time between the 1st and 2nd racking depends on how long it takes to convert all the sugar to alcohol. To accurately determine whether all the sugar has been converted, and all the yeast cells are dead, a hydrometer is used.

For kit wines, it usually takes 2 to 3 weeks after the 1st racking to do the 2nd racking. Different wine kits have different instructions on when to do the 2nd racking. Check the manufacturer’s instructions to determine the appropriate time to perform the 2nd racking.

When using kit wines, the 2nd racking is the time to add all the stabilizing and clarifying agents. There are different agents used in clarifying wine, and these include bentonite and isinglass. These 2 agents bond to the remaining solids in wine, so that they become heavy and settle to the bottom of the container, becoming sediment. One week after adding the clarifying agents, rack the wine again.

Wine Racking Processes

Ways to Rack Wine in California

Instructions When Bulk-Aging Wines

If you are bulk-aging wine, you need to rack wine every 3 to 6 months, or more. This depends on the amount of sediment occurring during the process. During this period, you will notice additional sediment falling into the bottom of the wine, and if this happens, you will need to rack it again. If no sediment occurs, no racking needs to be done.

Is it Possible to Over Rack Wine?

Yes, it is possible to over rack wine, and you do not want that to happen. The biggest disadvantage to having extra rackings is that there is more chances of exposing the wine to oxygen. Every single time you rack your wine, you expose it to oxygen. Therefore, too much racking means too much exposure to oxygen, which will ruin the flavor of your wine.

Other Ways to Rack Wine

There are various ways to rack wine. You can rack your wines in any way you want, as long as you keep in mind the main goal, which is to get rid of the sediment. Racking can be done by pouring wine, draining it, siphoning it, or pumping it. Among these, pouring is the least recommended, because it has the tendency to disturb the sediment. Draining and siphoning is easy if the container of wine is 2 to 3 feet higher than the container receiving the wine. Another option is to use electric pumps. Electric pumps allow the transfer of wine from the first container to the second, without the need to elevate the first container.
Whichever method you use to rack your wine, you must always remember the main objective for doing so, and that is to leave the sediment behind. But it is also important that you do not get carried away, and leave to much wine behind. If you leave too much wine behind, more water or wine will be needed to top off your carboys, and this can negatively affect the flavor of your wine. In order not to leave behind too much wine, it is alright to carry forward some sediment.
When the wines are bottled and kept in a custom wine cellar, there is still the opportunity to allow the sediment to settle at the bottom of the bottle. This happens as you allow your wine bottle to rest safe and undisturbed in your custom wine racks.