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The Ripper Titration: Recent Improvements in Measuring SO2

handrawing of an old wine barrel

In the effort to create high quality wines, it is critical to maintain proper free sulfur dioxide (SO2) levels during all steps of the winemaking process. Keeping SO2 levels at optimum values is key to preventing the discoloration, off-flavors and unpleasant aromas resulting from oxidation and microbial contamination. Suffice to say that all those award winning wines going for $200 a bottle or more have the correct levels of sulfites added to them!

The problem with the task of maintaining SO2 levels is the tendency for this component to disappear over time. The SO2, typically added as a sulfite like potassium metabisulfite, undergoes an equilibrium between free and bound forms which is pH- and temperature-dependent. In addition, oxidation by atmospheric oxygen continually reduces SO2 levels especially when the wine is briefly exposed to air as occurs during racking and bottling. Therefore it is important to have a reliable method handy for measuring free SO2.
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An Encouraging Start in the Wine Analysis Business

hand drawing of grapes on a wine barrell

…continued from “How It All Began“.

In July of 2008, a year after my former company (Molecular Devices) was acquired, my position as Vice President of reagent R&D was phased out.  Soon after that I was able to wrap up my affairs in Palo Alto and join my wife Marcia in Encinitas near San Diego, where we had conducted a commuting marriage for the last 7 years.

Jobs were not plentiful at that time, especially in my field.  I started Sportsman Consulting and had a few clients, but it wasn’t much.  I also worked on a startup called Ascent Biosciences, but in December of 2009 the company moved away.
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How It All Began

"a line drawing of grapes being crushed"

I founded Vinmetrica in December of 2009 on the belief that I could put together products that would help winemakers like me.

This belief  crystallized over several years and several events.  In 1993 I moved to Palo Alto with my family after living in Indianapolis for 8 years working as a research scientist at Eli Lilly.

We bought a house that had a venerable apricot tree in the back yard.  This tree was probably a remnant of the fruit orchards that used to occupy most of the Silicon Valley area in the early part of the 20th century.

apricots in a tree
Too Many Apricots?

It was a very productive tree, and after making several cases of apricot jam one summer, I still had several pounds of apricots.

It occurred to me to try to make wine out of them.   It wasn’t long before I was fussing over 5 gallon batches of apricot wine, and gradually I found myself learning the ropes of fermentation chemistry.
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