Tag: sulfites

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Some notes on sulfites, pH and TA

Since harvest is again upon us all, we at Vinmetrica thought it would be a good time to share a few tips on measuring and adjusting the three key parameters you need as fermentation begins and shortly after: pH, TA and free SO2.

First, just a reminder that we have lots of information on our web site (www.vinmetrica.com).  You might want to browse through our Support section on the home page.  There you can find useful resources like videos, the latest version of the manual for your instrument, and our troubleshooting guide.

Second, we recommend you look through the latest version of your manual to refresh your memory as needed!

Measuring and adjusting pH and TA

Measuring pH is technically simple.  You calibrate your pH electrode, then insert it into the wine sample, let it equilibrate a few seconds and take the reading.  Here are some tips to keep it from going awry. Keep Reading More!

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Not Getting An SO2 Reading.. Why?

We get this question a lot so we thought we would discuss it here.  [Note: Most of this information is available on our troubleshooting guide under SO2 Problems]

There’s two situations that may cause concern about the reading.

  1. Your instrument indicates an endpoint (beeps) right away, either before adding any SO2 Titrant, or after adding just 1 or 2 drops.
  2. Your instrument apparently never indicates an endpoint, even after titration with a large amount of the SO2 Titrant.

Situation (1.) happens a lot. Most of the time, this is just the normal endpoint response, telling you that your wine’s ppm of free SO2 is zero. To verify that the endpoint indication is valid, add 1 drop of 10% KMBS and stir.  The signal should drop to below 50 right away, and the endpoint indicators should stop signaling.  If the endpoint signaling does not stop, you may have a problem with the instrument.

Situation (2.) also crops up from time to time. Let’s say you are running an SO2 test on your wine and you use the ENTIRE 5mL syringe of SO2 Titrant, but your instrument stays on 0.00 or a low number, indicating that you still haven’t reached the endpoint. This would normally mean you have over 100 ppm free SO2 in your wine. But you’re pretty sure there isn’t that much SO2 present. So your instrument must not be working, right?

Actually, it might be working just fine! Keep Reading More!