In home brewing and wine making, ‘racking’ means syphoning the brew off the yeasty sediment that gathers at the bottom. This helps prevent off flavours developing and reduces the risk of bottles exploding later. Racking involves using a syphon tube to draw the liquid off the sediment without disturbing it. A variety of gadgets are available to make this easier and more successful.
When you ferment any liquid in home brewing and winemaking, the intial brew can look and smell pretty revolting. That’s because large quantities of yeast have grown in the liquid, and some pretty complex chemistry has gone on too. When fermentation slows down, the spent yeast cells fall to the bottom along with particles of fruit pulp and solids formed during the brewing process.
When this happens the brew ‘clears’ from the top down, and starts to smell more like the finished product. The unwholesome layer of yeasty muck that forms on the bottom of the fermentation vessel is called the ‘lees’. To avoid off flavours developing, it’s usually important to get your brew off the lees as soon as possible. This process is known as ‘racking’.
How to rack home brewed beer or wine
- Sterilise the syphon tube, new container and airlock or lid. Flush the tubing through with sterilising liquid, and rinse everything at least twice with clean water afterwards.
- Put the container full of cleared brew up on a bench or stool. Try to move it gently so as not to disturb the sediment. Put the new container right beside the original one, but lower down. The bigger the difference in height between the two ends of the syphon tube, the better.
- Carefully put one end of the tubing into the brew, stopping about 5cm above the layer of sediment. Either have someone hold it absolutely steady for you, or secure it somehow (see ‘equipment’, below). Take the other end of the tube below the level of the brew. Using your mouth, suck the end of it until liquid rushes down the tube.
- As soon as the liquid is flowing, quickly put the lower end of the tube into the new container. Gravity will gradually move the liquid from the old container to the new one. Be patient!
- When the level of liquid in the original container approaches the end of the syphon tube, gradually lower the tube down towards the sediment. You may want to gently tilt the container towards the side the tube is on, so that you get as much liquid as possible before the sediment is sucked up. If you look at the image above, you’ll notice that a catalogue is being used to provide the tilt.
- The transfer is finished when either air or sediment gets into the syphon tube. If more than a small bubble of air gets in, the tube will empty from both ends. If sediment does get into the tube, put your finger over the bottom end of it before the sediment reaches it and take the tube away. Finally close the new container with its lid or airlock. Wash the spent equipment ready to put away.
Equipment for racking
The only absolutely essential pieces of equipment for racking are a length of food-grade syphon tubing and a second container to syphon the liquid into. We recommend using at least a 1.5m length, so make sure you order enough. There are also various inexpensive gizmos that will make the job much easier.
The traditional way to start the syphoning process is to put the lower end of the syphon tube in your mouth and give it a good suck. This works well but contaminates the end of the tube, and you sometimes end up with a mouthful of your raw brew (sometimes pleasant, sometimes not). If this bothers you, a syphon pump makes the process a bit more hygeinic. Home Brew Online supply two sizes – a small one for demijohns, and a larger one for brew bins and carboys.
If you’re using a brew bin rather than demijohns, you’ll soon fine that syphon tubing is unruly and tends to move about if you don’t keep a good hold on it. This stirs up the sediment, which then gets sucked up along with the clear liquid. A tube clip keeps the top end of the tubing steady, leaving you free to worry about what the other end is doing. You can jury-rig your own clip out of clothes pegs and a rubber band, but purpose-made clips are sturdy and won’t give way when you’re least expecting it.
Syphon tube end
Since the whole point of racking is to leave as much sediment behind as possible, a syphon tube end is invaluable. This is a length of rigid plastic pipe that goes onto the top end of the syphon tubing, and has a cap on the end so that liquid is not drawn from the bottom of the pipe, but from a little way above it. This means that minor disturbances of the sediment are less likely to end up being sucked up the tube.
Taps and pinch clips
If you need to temporarily stop the flow of liquid through the syphon tube, you can simply put your finger over the end of the tube. This works well but isn’t ideal because, apart from the risk of contaminating your brew, it leaves you shackled to the tube with only one hand free. Using a tap or pinch clip gets round this problem. I favour a pinch clip, because it isn’t in direct contact with the brew so doesn’t need to be sterilised. It can also be used one handed, which is really important when you’re bottling your brew.
When to rack home brewed beer
Most beers are racked only once, right before bottling. When the beer has stopped frothing and clears from the top down, watch it closely to make sure there are no more tiny bubbles rising to the top. If you have a hydrometer, use it to check that the reading doesn’t change over three days, and that it’s in the range for bottling. Once you’re sure fermentation has stopped, it’s time to rack and bottle.
When to rack homemade wine
Most homemade wine is racked at least twice. This is partly because clarity is so important in winemaking, but also because wines can take longer to clear properly than beers. Wine gets its first racking when the fermentation slows down to a level that allows the liquid to clear naturally from the top down. There may be a little mistiness, known as ‘haze’, but you can ignore that at this stage.
A little wine is always lost with the sediment during racking, but as you get the hang of doing it you’ll lose less and less. If necessary, top your brew up afterwards using cool, previously boiled water. Move it to a cool location where the temperature doesn’t change much, such as a garage or shed that doesn’t get direct sun, and leave it to clear.
In two or three months the wine gets a second racking to remove the relatively small amount of sediment that it has thrown. At this stage it should be absolutely clear and ready to bottle. If it is still misty, rack it anyway: some wines are prone to develop a ‘haze’ of tiny particles that take a very long time to settle. If this happens you can choose between giving it more time, or adding something to hurry things along. Substances that help hazes to clear are known as ‘finings’.
Whether you fine it or not, once your hazy wine has finally cleared you will need to rack it again just before bottling.