A brilliant, clear wine is synonymous with quality. You may craft a superb tasting wine but if it doesn’t pass the clarity test it will be judged poorly. So it’s important for you to remove any turbidity from your wine before bottling. I’ve found that the best way to assure this is to use a three-step clearing method. I begin by adding finings followed by mechanical filtering. I then let my wine sit for a few days before bottling. Let’s look at these three steps individually.
It’s important that you fine your wine before filtration. Cloudy or hazy wine will quickly overload your filters.
1. Most wines will eventually clear on their own but this can take some time. Finings are substances that act as a catalyst to speed up the clearing process. Most finings are organic such as gelatin and isinglass but there are some inorganic finings with bentonite clay being the most popular. For the most part, finings work by providing a positive charge that attract yeast cells which are negatively charged. Think about how a magnet works and you’ll get the idea. As the attracted yeast cells clump together they become heavy and gradually fall to the bottom of the fermenting vessel leaving clear wine behind. Suspended yeast is the most common cause of turbidity in wine but there are other substances that produce hazes. Some of these have a positive charge which is different from the yeast. That’s why most wine kits contain two packets of finings. One will be negatively charged and the other positively charged. This covers the whole spectrum.
2. Filter media will mechanically separate wine from yeast and other solids. The most effective way to do this is to force your wine through a series of filter pads or a cartridge. This is accomplished by using a pressurized filtering machine. You can also filter by gravity but this is less effective and is usually restricted to small amounts of a gallon or less. Filter media comes in various porosities and grades depending on the application it is meant for. The wine is forced through the filter and solids are trapped in the pads or cartridge. Less porosity will trap smaller particles. Filter porosity is rated by microns. Most winemakers will use 1 micron polishing filters. You can follow-up a 1 micron filtration with a .5 micron filtration. This is considered sterile filtration and will remove over 80% of any yeast that passed through the 1 micron filter. I recommend this extra step.
It’s important that you fine your wine before filtration. Cloudy or hazy wine will quickly overload your filters. If this happens you may have to change your filters several times during the process. This can be expensive and frustrating.
3. I let my wine sit for a week or more after filtration. I do this in a cool area. I use a refrigerator in the summer time. This will aid in the precipitation of any bitartrate crystals that may occur. I’ve also found that if I let my wine sit for a period of time after filtering it sometimes throws a slight sediment. After a period of rest the crystal-clear wine is easily siphoned off any residue that may be at the bottom of your carboy. You’re wine is then ready for bottling.
That’s my method for brilliant and clear wine. Try it the next time and let me know if you see a difference.