Opti-red, is a yeast derived mix of polysacchrides, which are designed to bind to polyphenols/tannis and provide fuller body and better colour stability.

I would not add more than the recommended dose, not becuase it will do you harm, but due to the fact the manufacturer has calculated and adding any more is a waste and may advresely affect the finished wine.

If it is about to go out of date, I would use what is recommended then dispose of the rest.

Regarding best before dates their data sheet states: "Opti-Red should be stored in a cool, dry place. Un-opened, Opti-Red has a shelf-life of 3 years."

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