Free SO2 "standard"

[wine_wizard]

OK,

So I buy ph calibration standards for cal /checking my ph meter.

And with a decent scale, di water, and sugar, can make a calibration checking solutions for my refractometer and hydrometers.

So now I am starting into free so2 testing. ( aeration / oxidation method )

So any ideas on buying / making a "calibration" solution ?
( just adding kmeta to di water will give some level, but not sure how the bound vs free so2 will end up ? )

May send some wine to the Virginia Tech enology lab
lab URL
for a $45 one time check ... (but they want a whole split to test

 

[ibglowin]

There is no calibration standard. Just calibrated reagents (acid and base).

Since your testing for free SO2 and SO2 is always trying to react with Oxygen and be bound up its impossible to make a stabilized standard unless you want to make it up each and every time right before you do an analysis.

Make sure your reagents are fresh and at room temp and that you allow the same amount of aeration/oxidation time for each analysis. Then make sure you go always start and end each titration at the same point on the titration curve.