Acid Substitute

Hi Mike,.

I think he means the aeration/oxidation reaction to measure free SO2. The acid just serves to put the pH of the wine below 1.0, so that all the SO2 in solution exists as molecular SO2 rather than HS03-.

I've thought about using sulfuric acid, but I wasn't sure if you would blow over something that would look like, or react like sulfuric acid in your hydrogen peroxide. Sulfuric acid is ultimately what you're titrating for to meausre SO2.

Dave

**************************************************************************** Dave Breeden snipped-for-privacy@lightlink.com

Clyde,

I'm not sure what you mean by an A/O, but if it's some kind of acid titration, you've got to take into account that phosphoric, H3PO4, has

50% more H+ ions per mole than sulfuric, H2SO4. Sorry I can't be of more help.

(snip) I've thought about using sulfuric acid, but I wasn't sure if you

Dave,

Ah, I learn something every day. Thanks.

I suspect you're right: that the common ion effect might interfere a bit with the ultimate rxn, but a rough result could probably be obtained, if that was adequate. I'd want to double check for peace of mind though.

Clyde I am rather puzzled as to what you intend adding Phosphoric acid too. unless Soft drink manufacturers use phosphoric acid in some of their products to provide a pleasant tartness.

Sulfuric Acid Product Type: Liquid Also known as oil of vitriol or dripping acid, it is the most important and widely used industrial acid. It is used in the manufacture of inorganic and organic acids, electronics, batteries, neutralization, synthetic drugs, technical gasses; an important laboratory reagent; a nitrating, sulfonating, pickling and drying agent; used in preparing soluble phosphates.

Stephen SG

Hi, Clyde -

Yes, I'm pretty sure that's OK. All you're doing is bringing down the pH so the free sulfite all becomes molecular free SO2 and you can drive it off with a gas stream into H2O2. The actual amount of phosphoric or sulfuric isn't critical - just as long as it's in excess.

I noticed that Titrets use phosphoric acid for their reverse Ripper analysis. I've always used 25% sulfuric when running a Ripper. I suspect they're interchangeable, with the sulfuric being cheaper but the phosphoric being safer to handle.

Tom S

Thanx all for the responses. As usual, I was cutting it to the wire, so here's a rundown of how it went.

I checked the pH of the little bit of

25% phosphoric on hand, and it was 0.50 pH. So then I went about making a suitable concentration of sulfuric, which came out to 0.60 pH at 5%. I just used slightly more of this mixture to compensate for the higher pH, but that was probably overkill.

It seemed to work out fine. I tested this against a ripper and the results were consistant. Was testing three barrels of red (pH of 3.45) which were tested, adjusted, and topped 3 months ago. For the record, these wines were all in the

35-38 ppm range and were bumped up by 15 ppm for bottling. We bottled the blend of the three yesterday, so I was desperate for an accurate reading.

Thanx again everyone for responding. I'm assuming that the misunderstandings/questions about what I was doing have been cleared up through the rest of the thread, but if anyone has any other questions or comments...

clyde Steelville, Missouri, USofA

No thanks required. A few bottles of whatever that was you bottled will cover the consulting fee. ;^D

I hope it was Norton...

Tom S