By Ed Kraus
The When's, Why's & How's
Racking is an essential part to making any sound wine. It is a process that, on average, should be performed 2 to 4 times throughout the winemaking process. Doing so in a timely manner will aid in the clarification of the wine and help to inhibit the production of unwanted off-flavors.
What Is Racking?
Many home winemakers that are new to the hobby are sometimes thrown off by the term, at times, confusing it with meaning to bottle the wine, or worse yet, interpreting it to mean that they need to seal up the wine fermentation vessel air-tight in some fashion. Both misinterpretations can lead to disastrous results.
There are some variations on the definition of "racking" that can be found from one winemaking book to the next. But put very simply, racking means to siphon the wine must from one container to the next, so as to leave any sediment behind. In fact that is the sole purpose of racking, "to leave the sediment behind."
When To Rack
THE FIRST RACKING:
The first racking should normally be done around 5 to 7 days into the fermentation. This is an optimum time to rack a must for several reasons.
The first being, this is the time you will need to put the fermentation under the protection of an air-lock. And, this usually means moving the must to another container, anyway. The reason an air-lock is needed at this point is because this is when the fermentation will dramatically slow down. When the wine yeast becomes less active, the must is no longer able to sufficiently protect itself from the continuous, long-term threats posed by outside contaminants. The must needs the protection of an air-lock.
Secondly, it is at this slowing period that you will usually find that around 70 to 80 percent of the sediment will have already occurred. It will take much longer for the last 30 percent to show up. So, racking the wine on the 5th to 7th day is a good idea from a timing standpoint--an optimum time to get the bulk of the sediment out of the way.
The third reason for racking a must at 5 to 7 days is to remove any pulp that may be present. If you are dealing with fresh fruits as opposed to packaged juices, you will want to get the pulp out of the must at this time. Leaving the pulp in the must for a longer period of time could result in a wine that is too harsh tasting; and any shorter period of time could result in a wine that has less body and character than you may prefer.
THE SECOND RACKING:
The second racking should be done when the fermentation activity is complete. This could be just a few days after the first racking, or it could be up to 4 or 5 weeks after the first racking. It simply depends on how fast your fermentation has come along.
Once the racking has been done, you will want to put the wine airlock right back on. The must will now need more time to become completely clear.
THE THIRD RACKING:
The third and--quite often--the last racking should be done after the wine has completely cleared up. Again, this is an opportune time to get the sediment away from the wine. It only makes sense to rack the wine away from the sediment as soon as all of it has occurred.
Other rackings may need to be performed in certain situations, such as when bulk aging a heavy red wine, for example. Every 3 to 4 months it would be wise to rack the wine off any sediment that may have occurred over the coarse of long-term bulk storage. Sediment can occur throughout this storage time due to instabilities that may exist in the wine.
Another time that an additional racking would be required is if you decide to use finings or clarifiers in your wine such as Bentonite or Kitosol 40. This would require you to do a racking once before treating the wine and once again after the effects of the fining or clarifying process are complete.
TOO MANY RACKINGS:
It is possible to rack a wine too many times. The additional disruptions to a resting wine can work as a negative by way of over oxidation and/or the general deterioration of the wine's flavor. So, please do not get the idea that more is better when it comes to racking your wine.
Why Is Racking Necessary?
Why are we concerned about getting the sediment away from the must in such an timely manner?
With the exception of some solids that may have settled from the fruit, most of the sediment is the result of dead or inactive yeast cells falling out of the must. The yeast that is initially introduced into a must at the beginning of a fermentation, will multiply itself to anywhere from 100 to 200 times the original amount that was put in. Generation after generation of dead yeast cells is the bulk of what you see lying at the bottom of the fermenter.
Towards the end of fermentation there is a fairly sizable group of healthy, active yeast cells floating throughout the must that are running out of food (sugar). Once all of the sugars have been consumed, this active, now-starving group of yeast will start a process that can only be described as cannibalization.
The active yeast will instinctively start producing an enzyme that will break-down the dead yeast cells that lay on the bottom. This is done so that dead yeast's nutrients can be released and utilized by the still-active yeast. This break-down process is known as "autolysis" and its effects can eventually ruin a wine. If given enough time--weeks, not days--this process can produce off-flavors in a wine that range from bitter, to rubber, to even metallic.
Another reason for racking wine is to aid in the clarification process. If no rackings where ever performed, what you would eventually have is a container of wine that was clear on top, but with a thick, hazy layer at the bottom. In a typical five gallon batch, this hazy layer could be anywhere from 1 to 5 inches thick. This would be in addition to the heavy layer of sediment that would lay solid on the bottom.
How To Rack A Must
The process of racking your must is fairly straight forward. You simply start a siphon. The real trick is to do the siphoning without stirring up the sediment. You need to siphon the must "quietly," as I like to say.
You can rack your wine with nothing more than a length of food grade hose, but this can get a little tricky, especially when you get down to the end of the siphon. A hose will have a tendency to move around and draw from places you don't want it to--like in the sediment. Or worse yet, the hose may curl up out of the liquid causing you to loose your siphon all together.
This is why many people prefer using a Racking Tube on the end of their hose. A Racking Tube is simply a rigid piece of clear tubing around two feet long. It acts as a wand allowing you to point where you are drawing from within the container. The end of the Racking Tube has a diversion cap that helps you to draw away from the sediment, instead of in the sediment.
Starting the siphon can be done by sucking on the end of the hose--the old fashion way. However, we do not recommend this for obvious reasons. But, another alternative to this would be to use The Automatic Siphon.
The Auto Siphon is pretty slick to use. It is a Racking Tube and priming pump all in one. You simply put it into the must. Slowly pump the Auto Siphon up and down one time, like a bicycle pump, and your siphon is started.
How To Rack Efficiently
When doing the first 2 or 3 rackings, don't worry about leaving all of the sediment behind. Get as much of the liquid as you can, even if it some of the sediment comes with it. It is when you do your final racking that you will want to leave all of the sediment behind at the expense of some wine. By racking your wine in this way you will experience less loss of wine with no consequence to quality.
Using Sulfites When Racking
After racking a must that has completed its fermentation, it is recommended that a 1/2 dose of either Campden Tablets or Sodium Bisulfite be added to the wine. The sulfite gases that are released from these products will drive out any air that may have been introduced to the wine during racking. This will help to reduce the effects of oxidation on the wine.
During a fermentation this is not an issue. The CO2 gas that is produced by even a slow fermentation will quickly drive out any oxygen that may have gotten into the wine.
NOTE: Do not add sulfites to an active fermentation. This will cause the fermentation to slow down and become sluggish. It may possibly even stop the fermentation all together.
Ed Kraus is a 3rd generation home brewer/winemaker and has been an owner of E. C. Kraus since 1999. He has been helping individuals make better wine and beer for over 25 years.