Following is some good info from Jack Keller's web site:
Pectin Haze: The most common cause of a haze in wine is the presence of pectin, which forms gelatinous solutions in the wine. The problem is aggravated if the must is initially boiled to extract flavor, color or both. To check if a haze is pectin in origin, add 3-4 fluid ounces of methylated spirit to a fluid ounce of wine. If jelly-like clots or strings form, then the problem is most likely pectin and should be treated.
To treat the wine, for each gallon of wine draw off one cup of wine and stir into it teaspoon of pectic enzyme. Set the treated sample in a warm place (70-80° F.) and stir hourly for four hours. Strain the sample through sterilized muslin cloth and add to the bulk of the wine. Leave the wine at 70° F. for 4-5 days. The haze should clear. If it does not, strain the wine through sterilized muslin cloth and then through a vacuum-pumped filter. If it still does not clarify, the problem was misdiagnosed.
