Is beer better filtered or unfiltered?
For beer brewers and connoisseurs alike, this question is likely to come up sooner rather than later. I would first tell you that this isn’t the full question as not all methods of filtering beer are the same. What it all comes down to is clarity and the prevention of sediment in bottling. Most homebrew and unfiltered beers lack the clarity of brewery filtered beers, and often will have a small yeast accumulation at the bottom of bottles from naturally carbonating in the bottles.
Now how do these big filtering breweries do it? In reality, a brewery that filters beer will likely have a few stages of filtration to separate the different size impurities that remain within the beer.
For our purposes, we can break it down to three main classes of beer, unfiltered, standard membrane filtered as above, and centrifugal filtered. Centrifugal filtering doesn’t involve passing the beer through any filters, and
Membrane filtering – Generally there are four main clarification stages including primary filtration, trap filtration, fine filtration and final membrane filtration. Filtration at each stage is for a particular purpose: 1. Primary filtration removes solids and bulk yeast from the beer. 2. Trap filtration removes DE or other process additives 3. Fine filtration may reduce yeast level and removes fine particulates that could foul a final membrane filter. 4. Final membrane filtration removes organisms (bacteria and yeast) that could spoil the packaged beer. Via Probrewer.com
Centrifugal filtering – Doesn’t involve passing the beer through any filters, as a result it seems to achieve good to great levels of clarity without affecting the other properties of the beer. This is a huge benefit over the traditional membrane filters as some theorize that they affect the final beer product taste among other characteristics. This method is very uncommon and to my knowledge is only in place at a couple breweries such as Deschutes Brewery in Bend, OR.
Unfiltered – Some purists out there believe this is the only way to enjoy beer the way it was meant to be enjoyed. Unfiltered beer will likely have murky clarity, some hop and yeast “contaminants”, and a pure unfiltered taste. Although it is technically unfiltered, many brewers using this method will use brewing strategies that reduce the amount of yeast and hops remaining in the beer. Basic chemical tablets can be used during the brew process to increase clarity of unfiltered beers as well.
Based on my studies, centrifugal filtering is the best bet for delivering a pure unadulterated beer taste without sacrificing clarity or having contaminates in the final product.
Follow me on Twitter for all your beer and cider information @Tanner_Brews