Free SO2

[Steve]

What is the recommended free SO2 for a white wine prior to bottling?


It is a Pinot Grigio...

 

[Coaster]

I'm no expert in this area but I beleive the target is about 50-75 ppm.

 

[masta]

Steve,


The amount of free SO2 needed to properly protect your wine at bottling is most dependent on the pH than any other factor. A good target is 35-50 ppmand the latter is best for longer term storage.


Here is a portion of a article I wrote for a past news letter that helps explain it in more detail:



pH and Sulfites


Molecular SO2 is the principal form of free SO2 that is responsible for anti-microbial activity. The amount of molecular free SO2 available is a direct function of the pH of your must or wine. Since the lower the pH (more acidic) the more molecular SO2 is available, sulfite additions should be calculated with reference to pH. Not every home wine maker has a pH meter so general guidelines are written so the amount of sulfite added would provide the protection your wine needs based on a average pH for the style of wine. It has been written that the amount of molecular SO2 needed to protect your wine is a level of ~0.8 mg/l. The chart below shows the amount of free SO2 needed to provide protection of molecular SO2 at the level of 0.8 mg/l. Remember that the level of free SO2 will slowly decrease over time, so if you plan to age your wine for an extended period of time you need to increase the amount of sulfite added so you don’t lose the protection over the years


Free SO2 required for a level of 0.8 mg/l molecular SO2
<TABLE borderColor=#0033cc cellSpacing=0 cellPadding=10 align=center border=2 ="tableNew"><T><T>
<T>
<TR ="#ffff00">
<TD noWrap width="52%">
pH Level</TD>
<TD noWrap width="44%">
Free SO2 </TD></TR>
<TR>
<TD width="52%">
2.8 </TD>
<TD width="44%">
8 </TD></TR>
<TR>
<TD width="52%">
2.9 </TD>
<TD width="44%">
10 </TD></TR>
<TR>
<TD width="52%">
3.0 </TD>
<TD width="44%">
12 </TD></TR>
<TR>
<TD width="52%">
3.1 </TD>
<TD width="44%">
16 </TD></TR>
<TR>
<TD width="52%">
3.2 </TD>
<TD width="44%">
20 </TD></TR>
<TR>
<TD width="52%">
3.3 </TD>
<TD width="44%">
25 </TD></TR>
<TR>
<TD width="52%">
3.4 </TD>
<TD width="44%">
31 </TD></TR>
<TR>
<TD width="52%">
3.5 </TD>
<TD width="44%">
39 </TD></TR>
<TR>
<TD width="52%">
3.6 </TD>
<TD width="44%">
49 </TD></TR>
<TR>
<TD width="52%">
3.7 </TD>
<TD width="44%">
62 </TD></TR>
<TR>
<TD width="52%">
3.8 </TD>
<TD width="44%">
78 </TD></TR>
<TR>
<TD width="52%">
3.9 </TD>
<TD width="44%">
98 </TD></TR>
<TR>
<TD width="52%">
4.0 </TD>
<TD width="44%">
124 </TD></TR></T></T></T></TABLE>



Edited by: masta

 

[Wade E]

Booyah Skeedaddy! I need to read more! Masta, sorry I used your saying but the chart left me speechless!</font></font></font>
Edited by: wade

 

[Steve]

Thanks for the info masta, we can always count on you...

 

[Mack]

Masta, thanks guy for the info on SO2. I would like to do some of the SO2 testing
also. As I understand it, you can test with ph strips or buy a digital
tester, which has to be calibrated (as I read it). Which is best? Thanks.


Mack

 

[rshosted]

You'll want to get a digital one if you want it to be accurate. The PH strips only get you in the ball park.

I bought a digital PH meter and love it. It is easy to use. I calibrated it when i got it. I kind of cheat and don't always calibrate it. I do however test it on distilled water to see if it is in the right neighborhood.

Toys, toys, toys, toys, toys.....