Addressing the aspect of sodium concentration

[Kit_B]

I've been seeing concerns for the amount of sodium we have recommended adding to brewing water, via campden additions.
Apparently, some folks are worried.
Let me put your minds at ease.
We can address this via simple mathematics.

Pure Sodium Metabisulfite is Na2S2O5.
This breaks down to:
Two Sodium
Two Sulfur
Five Oxygen

The molecular weight of this is 190.107 g/mol.

If we look at the individual weights of the components in this molecule, we see:
Sodium = 22.9898 g/mol
Sulfur = 32.065 g/mol
Oxygen = 15.9994 g/mol

So...Breaking this down into rough percentages:
Two Sodium atoms make up 24.19% of the total molecular weight
Two Sulfur atoms make up 33.73% of the total molecular weight
Five Oxygen atoms make up 42.08% of the total molecular weight

We are suggesting a small Na2S2O5 addition of 100mg/l, to your mash water, before dough-in.

This measurement further breaks down to approximately 24.19ppm of Sodium.
Looking at the paper you will plainly see that 24ppm has been stated on Page 4, Section 2.1 Water.

Rest easy...We're not trying to hurt you with Sodium content.

[Roachbrau]

I fear people aren't realizing how small the quantity actually is. There are 1000 milligrams in a gram. Most people measure water salt additions in GRAMS, not MILLIGRAMS.

I use about 35L (9.25 gal) water per 5 gallon batch. If I treated ALL the water at 100mg/L, that would still only be 3.5 grams of total sodium metabisulfite. That's about half a teaspoon or so of the powder.

People frequently add 5-10 grams of gypsum to pale ales and such

[mchrispen]

Good post Kit_B. I have been looking at the same. 24 ppm is not a problem with sodium.

One additional benefit that shouldn't be underplayed is the complete and total degradation of chlorine or chloramines. The latter especially requires an interminably slow filter through carbon block filters to remove. At the rates many people run their carbon filters, chlorine can easily break through, even if greatly reduced. Chloramine is even more difficult to filter - so metabisulfate is the only cost effective solution at home.

Judge a few beers at competition and even the good beers often have strange low phenols that are not appropriate (subjective, of course).

[Owenbräu]

Right, and to those worried that the sodium is impacting the flavor, add an equal amount of sodium to the control mash when you do the mini-mash comparison. That way they both have the same amount of sodium and thus eliminated as a variable for the flavor differences.