Filtering is the last step in your wine making process, and is done right before the wine is bottled. But should it be done at all? Once again, this is a decision the homemade wine makers must make based on personal preference, and each type of wine may require a different decision. Let’s examine the pros and cons of filtering so you can make well informed decisions.
Why would you filter a wine anyway? Filtering can remove bacteria, leftover yeasts, fruit and grape pulp and other debris. Filtering can make a wine more stable, because by removing any leftover yeast you take away the chance that your wine will begin fermentation again by feeding on any leftover sugar.
Most red wines that have been bulk aged don’t really need to be filtered, and they seldom are by most wine makers. As a wine ages, the debris and solid particles will eventually fall out and the wine will clear on its own.
I’ve found that homemade wine made from kits doesn’t require ant filtering at all. These kits are supplied with juices and concentrates that don’t contain much if any pulp or other matter that needs to be removed. Additives such as oak chips won’t be bottled, and oak powder will precipitate out while in your glass carboy.
White wines can be a different matter. Some wine makers will filter these to put a final polish on an already clear wine.
Arguments against filtering have some valid points. One good point is that by filtering a wine you remove all the particles that would normally form a fine sediment over time while aging your wine in the bottle. This sediment has a way of contributing to a wine’s character by mellowing out the harsh “bite” of a wine.
There are a few kinds of filters available to homemade wine makers. One is a gravity filter that works by siphoning your wine from the container to your bottles while it passes through a filter pad. This method can be extremely slow. There’s another type of filter that works by using a hand pump to force the wine through the filter. Still another type uses an electric pump that takes away a lot of the work associated with had pumping.
There are three basic types of filter pads, a coarse, a medium one and also a fine one. If your wine has already aged for some time I believe the coarse filter is probably not necessary. If you pass your wine through a medium filter pad you will notice a difference in the color and the clarity. The fine pad is capable of actually stripping the color from your red wine, and will remove virtually all of the yeast cells and thus eliminate the chance of re-fermentation.
Remember, filtering is the absolute last step in your wine making process, even after adding Campden tablets.
To filter or not to filter? It’s a question that homemade wine makers face all the time. Armed with the above knowledge you can now make an informed and confident decision.