Filtration is a process that is usually carried out right before bottling. It involves passing the wine through a filtration medium to separate any particles from the liquid in order to remove the opaqueness of the wine and create a clear and stable final product. The filters remove any sediments such as dead yeast cells and bits of grapes left from the winemaking process.
There are two reasons to filter wine: aesthetics and microbial stability. On the aesthetic side, filtration can make a wine more polished both in the glass and in the mouth; often creating a rounding effect that softens the wine‟s edges. If your wine is sound with no flaws, then you can decide if you want to further shape your wine by filtering it. However, if you have residual sugar or Malic acid left in the wine, or there was a problem with Acetobacter or Brettanomyces during the ageing/storage period, then filtration is no longer an artistic decision; it becomes the only way to guarantee microbial stability for the wine.
A multitude of different types of filters can be used, each cleaning the wine using a different method and level of intensity. The most normal filters either push the wine through a series of filtration plates or cartridges using intense pumping, but these can be quite harsh on the wine. We try to use as gentle filtrating as possible at Binivista to only just filter enough to ensure that the wines we ship to our members are stable and showing at their best. In general you can say that the more intensely you filter the more of also the good stuff in the wine you remove. A gentle filtration on the other hand aims to only remove the potentially problematic particles in the wine. So we have decided to use a highly sophisticated "tangential flow filtration" system that, without getting too technical, very gently lets the wine flow through some membranes that catches only the stuff that we do not want in the wine and nothing else. Again, only the best for our wines!
Filtration can stress a wine and cause it to temporarily “fall apart” right after the process. However, the filtered wines put themselves back together just fine over the following weeks. This is why we always let the wines rest for some time at the cellar before shipping them, as that also adds to this "shock" effect.