I'll be the first to agree that if you have experience with a procedure that works, stay with it. However, the information on SO2 has been changing throughout the years, there's a lot of conflicting information out there. An article from 2012 indicates that the old charts shouldn't be applied to high pH wine, Ive included pieces from the original article below.
Sulfur Dioxide Basics Revisited March 2012 by Clark Smith
Thirty-two years ago my first published piece, printed in the inaugural issues of the University of California, Davis, Extension’s Enology Briefs,1,2 concerned the basics of conventional SO2 management. A table I worked out with pencil and paper in a Shields Library basement can still be found tacked up on winery lab walls throughout the United States. There are omissions I have since regretted, and it is high time for a rewrite.
The most important omission in my 1980 article was to point out the folly of applying the table to high-pH wines. If your wine is pH 4.0, you want to correct the pH, not try to stabilize its microbiology by maintaining 120 ppm FSO2. This applies to winemaking above 3.6, the peak of the bitartrate curve, which constitutes a natural watershed dividing winemaking into low- and high-pH regions. High-pH winemaking concerns itself mostly with red wines, which have more vigorous anti-oxidative phenolic reactions in this zone and greater maturation requirements.
The dominant theme of low-pH winemaking is focused on prevention and control. In high-pH winemaking, we often acknowledge that we have given up on prevention and try instead to direct the inevitable to a stable and agreeable outcome in which a microbial balance is sought rather than a draconian elimination strategy.
In low-pH winemaking, we stress the role of molecular sulfur dioxide to control the growth of microorganisms. Since its effectiveness as an inhibitor is greatly lessened at high pH, it is more sensible to forget about molecular SO2 in this zone and instead regulate free SO2 (FSO2).
Free SO2, which is substantially all bisulfite, should be maintained to combine with H2O2 as it is formed as a side product of chemical oxidation of diphenols. The reaction of sulfites and peroxide is the fastest reaction known to chemistry, and it may be relied upon to prevent the formation of aldehyde from ethanol oxidation. Since SO2 is depleted by this action and by aldehyde binding, it must be measured by aeration/oxidation and maintained at a reasonable level (20-30 ppm) throughout aging. Total SO2 should be measured to assess flavor impact (a soapy finish can be detected at about 200 ppm) and because of its inhibitory effect on malolactic bacteria at about 100 ppm.
A desirable consequence of sulfite oxidation to sulfuric acid is the liberation of free acidity. Over time, very high-pH wines tend to experience decreased pH and slightly increased TA. This effect can be ignored below pH 3.6 but can, during extended barrel age at pH 3.9, result in an increase of around 0.5 g/L in TA and a reduction of 0.1 in pH. Thus wines with sufficient reactive diphenol concentration can begin aging with unbalanced acidity (e.g. pH = 3.9, TA = 4.5) and finish on target (pH = 3.85, TA = 5.0).
The low-pH realm may be compared to in-town driving, where controlled navigation is paramount and little distance needs to be covered. We drive in town at 20 to 40 mph, corresponding to 3.2-3.4 pH. Maturing red wines more resemble freeway driving, in which there is less fragility and a greater imperative to traverse distance. The speeds with which we are comfortable on a divided highway are in the range of 55-75 mph, corresponding to pH 3.7-3.85. I must insist here that higher pHs are irresponsible. Wines at pH 4.0 are comparable to driving at 100 mph: demonstrably unsafe regardless of conditions.
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