The alcohol, low oxygen content, relatively low pH, hops extracts (alpha-acids) and dissolved carbon dioxide in beer inhibit the growth of pathogenic bacteria. That is why beer has been a safe drinking alternative for so many centuries. However, there are microorganisms that can survive and even thrive in beer and spoil the flavor and aroma of any good brew.
While filter ratings are an important indication of how well a filter will remove particles of varying sizes from a fluid or gas, it is important to note that nominally rated filters from different manufacturers can have the same rating, but yield different results. The opposite is also true – nominally rated filters from different suppliers can have different ratings, yet yield the same result. Naturally, this can create confusion and impact your filter buying decisions.