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The results of a 12 month CMC trial are in!    What have we learnt?

 

At twelve months both the white and red wines treated with CMC remained tartrate stable. However the colour precipitation caused by CMC would appear to preclude its use in red wine.

From this trial we can conclude that CMC’s can successfully cold stabilise white wine for at least twelve months. However the wine needs to not be initially too unstable as determined by the Stabilab DIT% test. Analytical parameters like pH & TA were not affected as is the case with some other cold stabilisation techniques. Also Alcohol, Residual Sugar, Volatile acidity and turbidity remained unaffected.

As noted by Janice McDonald, Senior Winemaker for Burch Family Wines “We did taste the wines and did not detect any differences in appearance, aroma and taste in the wine treated with CMC and the control”

Apart from the known constraint caused by CMC which after addition can cause filterability issues for 48hrs we have observed several other effects which need to be considered when deciding to use CMCs.

Preparation issues associated with the dry/granular forms of CMC may cause issues in wineries, as high shear forces (very vigorous stirring) are required to dissolve the CMC.  Liquid forms of the CMC are easier to handle in large quantities.

Young white wines maybe too unstable for CMC use. So analysis like the Stabilab DIT% test needs to be performed to assess wine stability and potential usefulness of CMC to achieve stability.  White wines with Tsat K values of 15-16 will have a better chance of stability with CMC.

CMC ability to precipitate colour would seem to make it unsuitable for use in red wine. This also makes questionable CMC’s usefulness in tartrate stabilising Rose, it maybe prudent to do a bench trial to assess colour precipitation in Rose's, prior to use.

General Observations:

At Winechek we have been working with CMC products from various sources for about three years. Over this period we have experienced many successes and a few failures with regard to CMC use and I think relating the causes of the failures would be of use to the industry.

I would have to say that most of the problems come from trying to “bend the rules” of the manufacturers instructions on CMC use and these include;

  • Last minute additions of grape juice concentrate. Amounts equivalent to 1g/L residual sugar have caused issues.
  • Trying to reduce costs by performing trials and using less CMC than the manufacturer’s specifications.
  • CMC addition to wine prior to course filtration and inline filtration to bottle. This was undertaken in an attempt to reduce wine loss in a small batch of wine.
  • Not checking if the wine is too unstable before CMC use.
  • Acid additions, particularly tartaric acid just prior to bottling.

Another issue we have found is that deacidification, which is known to cause major changes in tartrate stability, can continue to cause effects for over a week if not more. This can mean that a wine could be de-acidified, a few days later have CMC added, the next, be tested and appear stable and then a week or months later become unstable. This is something to be seriously considered and planned for when wishing to use CMC for tartrate stabilisation.

More in this category: Tartrate stability »

Last modified on Friday, 09 August 2013 16:32

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