A/O Free SO2 results

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ForzaItalia

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Hi All!
So I have some 2013 Amarone which I am about to bottle but wanted to make sure the free SO2 was at the right level before bottling. The pH is 3.3 and the first result after running the AO was 3 ppm free SO2. I ran the calculation to achieve a 26ppm level and added the appropriate amount of meta, .8 grams. Waited 2 days and tested again, next result was around 6.4 ppm. Added more so2 according to the calculation waited another coulple days and tested again. The free SO2 now is at 13.6 ppm. I am concerned that my results are not accurate and will over sulfite my wine. Does anyone have any experience with this type of issue? Thanks!
 
Are your chems fresh?

Are you using the Morewine A/O Rig?

The titration is a color endpoint change and thus takes some training and experience to master the endpoint.
 
The chems are pretty fresh. I just bought the hydroxide peroxide and my sodium hydroxide has been kept in the fridge and is less then a year old. I diluted 3% hydrogen peroxide to .3% and .1n sodium hydroxide to .01n. I have the vintners valley A/O setup. I guess my question is it possible for all this meta to get bound and not increase the free SO2. Or is it most likely the chems or way I'm testing.
 
I would not mess with diluting Peroxide or NaOH. First mistake. If you need 0.01 then order it don't try to make it. It is not uncommon for 50% of the first addition of Sulfite to become immediately bound. That is why wine kits come with 2-3X what you need to sulfite 6G of wine. Next thing is to start out with a neutral receiving solution. You need to titrate it to neutral endpoint so you are starting out with a neutral solution and not one that is acidic or basic.
 
Do I need to dilute to .01 sodium hydroxide and .3 hydrogen peroxide? Or can I just use the the .1 sodium hydroxide and 3% hydrogen peroxide for the test?
 
You need to use 0.01N NaOH as the 0.1 is too strong. Just buy it pre-made (and pre standardized) its CHEAP. You can use off the shelf Peroxide from the grocery store, no need to dilute. What are you doing for Phosphoric acid?
 
Ok perfect, I'll try that. I have 25% phosphoric acid. Should I be worried about the shelf life of this as well or does it keep well?
 

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