#### Dustin_J

##### Well-Known Member

Hi Brooothru,Need some help with basic math.

Sad to admit, it's been over 50 years since I struggled through college math. I'm stuck in an endless Do Loop (been 50 years since I did FORTRAN coding as well) and can't figure out where I'm making my error. It's not Diffy Q. Not even advanced calculus. We're talking basic algebra. Somebody help bail this 70 year old brain out of dementia.

Background: Trying to determine how much additional sodium (PPM) will be needed to account for in a brewing water calculation. From the LoDO brewing website, I know that 1 mg NaMeta solute in 1 liter of water results in 24 PPM additional sodium. My target volume is 23 liters, strike volume ~29.5 liters. I add .65 grams of NaMeta to my strike water to scavenge DO prior to mash-in. How many PPM does this increase the amount of sodium in both the strike water and final concentration in post boil wort? Solve. {Please show work}.

Brooo Brother

Keep in mind that, in water, 1mg/L ~= 1ppm. So, 1 mg of NaMeta in 1L of water yields ~.24 ppm sodium, whereas 100 Mg of NaMeta in 1L of water yields ~24 ppm sodium.

To get there, the NaMeta (SMB) molecular formula is Na2S2O5

The Elemental/Atomic masses of constituent elements are:

Na: 22.9897

S: 32.065

O: 15.9994

So, for Na2S2O5:

-Na: 22.9897*2: 45.9794

-S: 32.065*2: 64.130

-O: 15.9994*5: 79.997

45.9794 + 64.130 + 79.997 = 190.1064 = Total molecular mass of NaMeta

The Percentage Na in NaMeta, then (by mass):

- 45.9794/190.1064 = .2419. or ~24.2% Na by mass

So 1 mg of NaMeta in 1L of water should yield ~.242 ppm (Mg/L) of Na

Moving on to your stated additions:

.65 grams of NaMeta added to 29.5 L of water yields ~22 Mg/L (ppm) of NaMeta

Of that 22 Mg/L (ppm) NaMeta in your strike water:

- 24.2% is Na, so you're adding ~ 5.32 Mg/L (ppm) of sodium to your strike water

Final water/batch volume (~23 L) will be a product of both absorption/losses (from grain, Mash tun deadspace, tubing, transfer loss, etc.) as well as evaporation/concentration (boil off), so exactly estimating ppm NA in your finished volume is tough without knowing more. It should be somewhere between ~ 5.32 ppm (Assuming no losses are from evaporation, which isn't true) and ~6.82 ppm (assuming all losses are from evaporation, which also isn't true). The difference between these, of course, is pretty trivial.

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