pH and Sulfite

[Ernest T Bass]

After reading another post, a question came up. "Also, knowing your pH is
important for knowing how much sulfite a wine needs for preservation". Is this something related to a SO2 test kit, do you take the results from the SO2 test and reference it to the pH and that tells you how much sulfite to add to your wine just before bottling? Or, have I just deducted all of this from not knowing what I'm talking about. Could you explain how you use the pH to tell how much sulfite to add just before bottling using the pH reading?
Thanks
Semper Fi

 

[NorCal]

One of the first articles I read was regarding SO2. Because you are looking for free SO2 and the resulting free SO2 is a function of the PH, you must adjust how much is being added to have the same net effect. See the article and graph.

http://morewinemaking.com/public/pdf/so2.pdf

 

[sour_grapes]

Ernest, check out these resources, which detail the interplay between pH and SO2 required:

http://morewinemaking.com/public/pdf/so2.pdf

http://nanaimowinemakers.org/Winemaking/General/SO2Levels.htm

 

[whackfol]

Check out this article also:

http://www.brsquared.org/wine/Articles/SO2/SO2.htm

 

[Turock]

And it's not just proper sulfiting before bottling. It's wise to take an SO2 test around your first racking, if you used sulfite in the primary, so you know where you're at. After MLF a reading needs to be done too. Your test tells you the free SO2 in the wine and based on the PH of the wine, you'll know how much sulfite you should have. There's numerous charts out there to tell you how much sulfite is needed at a specific PH level.

 

[Ernest T Bass]

Thanks for all the help, looks like I have a lot of reading and trying to understand what I have read. One thing I have learned is that you have to know the present SO2 level before you can do anything. I make mostly red wine and from what I have read is that it's hard to determine the SO2 level in a red wine because the color change is hard to detect, but I'm working on it.
Thanks again
Semper Fi

 

[Turock]

If you can afford it, you can buy a Vinmetrica 100 for SO2 tests. It has a digital readout so you don't have to worry about looking at color change anymore. We use the Vinmetrica and it is a great way to monitor your wines.