Sodium Metabisulfite

How Would this impact the flavor of the beer if there were no chlorine present in the water. I understand what it does and is used for, I just would like to know specifically what it would do if no chlorine were present.

Well, it also scrubs oxygen. Australian brewers use it to control any effects of hot side aeration (or mash-wort oxygenation, as I think they call it).

As far as flavor issues. The chemical itself has a strong sulfur smell, but it the chemical breaks down in 6 to 24 hours so you really shouldn't have an issues.

p-nut said:

How Would this impact the flavor of the beer if there were no chlorine present in the water. I understand what it does and is used for, I just would like to know specifically what it would do if no chlorine were present.

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It is essentially sulfur dioxide in solid form with some sodium or potassium It is used in such small quantities that the sodium or potassium is not going to contribute to flavor. The sulfur dioxide, if it can't find any chlorine or chloramine to reduce will go reduce something else. That which doesn't get oxidized to sulfate will fly off in the boil. As with the potassium/sodium the sulfate ion remaining is at too low a concentration to be noticeable.

Winemakers use it at significantly higher proportions than what is needed for chlorine removal, with no meaningful flavor problems arising. Regardless, anything it does add in terms of flavor or aroma will dissipate with time.

In wine and mead it's 1 tablet per gallon of the finished product and you can taste/smell it in newly bottled stuff. It does evanesce with time however. In treating water it is 1 tablet per 20 gallons.