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Tartrate stability testing has become increasingly difficult to assess with the new stabilising products on the market.

At Winechek we can test reasonably quickly and objectively the stability of your wine with the Stabilab™.

 CMCs  & mannoproteins work in a very different way than previous processes to stabilise wine and so most of the traditional analyses for Tartrate stability won’t work well and at best only provide a rough guide pre addition. This includes our routine Tsat test and the 3 day at -4°C.

A lot of work has been done in Europe with CMCs and the Stabilab machine and so the two tests offered on the Stabilab have been shown to have good correlations with stabilising effects of the CMCs. We have been involved in analysis for CMCs and mannoproteins since early 2010 with our Stabilab.

I am sure that the CMC producers have informed you all of the state of the wine required for its use which may have included testing to see if the wine is not too unstable for CMC usage. The test we do to assess this is called a DIT% or degree of tartrate instability. Usually only wines less than 3 months old need testing or wines that have not been stored at cold temperatures. However if uncertain it maybe worthwhile doing a DIT% test for reassurance.

Post addition of CMCs we can perform an ISTC50 (Critical Tartaric Stability Index with a 50g/hL KHT addition) test on the Stabilab machine to confirm tartrate stability.

THINGS OF NOTE ABOUT CMCs;

  1. They precipitate colour and so are not good for use on Reds (better to use mannoprotein)
  2. Can cause turbidity and colour drop out in Rose so a bench trial may indicate potential problems
  3. Some young whites maybe too unstable for CMC use – do DIT% analysis to evaluate
  4. CMC additions does effect filterability directly after addition, so it is best to wait 48hrs before bottling  

THINGS OF NOTE ABOUT MANNOPROTEINS;

  1. They help to stabilse colour in red wines
  2. They are not suitable for use in young white wines

THINGS OF NOTE ABOUT THE ANALYSIS;

  1. Our Busselton lab has the Stabilab machine so send samples there
  2. We need 200mL for each analysis
  3. For DIT% it is preferable to have at least cellar bright wine
  4. If posting, either send in a plastic bottle or if in glass ensure it is well protected against breakage in transit
  5. Confirmation of stability by ISTC50 can be made directly after addition of CMCs (in the 24-48hrs prior to bottling)
  6. The tests take 5hrs for DIT% and 6hrs for ISTC50 plus 1.5hrs to prepare the Stabilab. Also we can’t do both tests at once although we have the capability to do 8 of either at one time. So results are generally sent mid-afternoon of the day following receipt into the lab

If you have any other questions please don’t hesitate in contacting me or have a look at some of the published articles attached.

Rodney Marsh

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Last modified on Thursday, 21 November 2013 09:37

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