What micron level is good for carbon filtering your water?

Question

I went and built a version of this filtration system, but the only filter I could find at Home Depot was a 5 micron. The guy in that thread seems to be using a .5 micron. I have been using water coming out of a Brita pitcher (which I love the taste of), however it is very cumbersome to do it this way, which is why I wanted to do this. So I have a few questions concerning water filtration on this,

1. Is a 5 micron enough? Is it to much?
2. Why does Brita not tell what micron rating their filters are? Better yet, many of the filter manufactures seem to not tell it.
3. Either way I go, should I drop a campden tablet in for good measure?

Answer 1

5 microns is fine for brewing water. At the micron/sub-micron level you're filtering yeast and flavor compounds. Some people do filter their beer at this level for clarity/consistency/packaging concerns, but that's by-and-large not necessary itself. For most municipal water, you're looking just to filter macro compounds, and 5 microns is more than enough, I think.

If you're using an active carbon block, you need to run it below one gallon/minute to have a chance to break down chloramines, which your water supply might use. Chlorine and chloramine will be reduced almost instantly by a small amount (let's say 50µg/gallon to be safe) of Campden. My regular process is carbon-block filtration of my brewing water at a not-particularly-reduced speed, and add potassium meta-bisulfate (Campden) for dealing with chlormaines.

Answer 2

0.5um is perfectly fine for water filtration. Keep in mind that the porosity of the filter is only good for removing non-solubilized particles in the water. Its the activated carbon or other elements that you want for neutralizing things like chlorine or other hazardous contaminants.

Even in the Britta, the pore size isn't whats stripping out the soluble flavor molecules that make the water taste odd.