Filtration 

Distilleries use filtration for a couple of reasons:

One of these reasons is to address the sediment or haziness issue in alcohol.  The issue with any filtration is that the more heavily you filter the product, the more of the "good" flavor compounds, color, and oak aging notes you may be stripping away as well.  

The other reason to filter, is to remedy unwanted, and harsh flavors from a final product.  Have you ever heard that you can take a very cheap bottle of vodka and put it through an active carbon filter (i.e. Brita) a few times and it will taste better?  It is true to some extent. 

 

Likewise, a product created from inferior ingredients or using production techniques that lead to unfavorable flavors being carried into a product can be cleaned up with the use of filtration.