Generally adding cocoa to jams is fine, though I've heard others say the chocolate flavor is very mild, so you may want to amend with a natural chocolate extract as well. (Cook's is excellent.)

Cocoa is alkaline (has a high pH) but is non-fat and a powder, so there's no water activity. Consider it safe in the way dehydrated peppers would be.

To compare your recipe's proportions you might look at this one posted some years ago by KatieC, an MFP and Idaho Extension employee:

Jeanne's Decadent Banana Split Conserve
Recipe By :Katie

Amount Measure Ingredient -- Preparation Method
-------- ------------ --------------------------------
4 cups thoroughly mashed bananas
5 cups granulated sugar
2/3 cup bottled lemon juice
1 teaspoon Fruit Fresh (absorbic acid)
1 tablespoon unsalted butter
1 package liquid pectin -- (3 ounce)
3 tablespoons pure cocoa powder
2 tablespoons light rum or rum extract
1 cup coarsely chopped walnuts

In a medium stockpot, combine the mashed bananas, lemon juice and Fruit Fresh. Gradually add in the sugar, cocoa powder and butter. Over medium heat, heat the mixture stirring constantly, until the sugar is dissolved. Increase the heat to medium-high and bring the mixture to a full rolling boil, stirring constantly so it will not scorch. Stir in the liquid pectin and return to a full rolling boil for 1 more minute, stirring constantly. Skim off any foam. Remove the stockpot from the heat, stir in the walnuts and the rum. Ladle into sterilized jars leaving 1/4 inch head space. Wipe rims. Cap and seal. Process in a water bath canner for 10 minutes for half-pints or 15 minutes for pints. Yields 9 to 10 half-pints.

One poster (sorry, don't remember who) said she felt chocolate flavor didn't stand out enough and recommended replacing the rum flavoring with chocolate flavoring. Or, of course, rum (either liquor or extract) and chocolate flavoring could both be used.

Carol

Awesome answer! Thank you so much for your time and advice! This forum is such a great resource as are you and others who donate your expertise to the rest of us! Even had the answer been no, it's great to know we have a place we can share all of this great preserving knowledge. Thanx again!

You are very welcome. I'm sure Dave or Linda_Lou or others could have answered just as well. I thought afterwards that if you have no objection to the alcohol a chocolate liqueur might be a nice addition (plain liqueur not crème de cacao).

Sometime you might want to do a search of the forum. There have been lots of discussions about cocoa in various jams. Chocolate raspberry comes to mind.

Carol