Cooking For Engineers

[jkesr]

I would like to learn how to determine the correct amount of sugar that is needed to make jelly. I have found recipes for the more common jellies but when it comes to the exotic fruits or such there are no recipes. I am certain that it must have something to do with the S.G. of the fruit or do I use a Refractometer? Is there a total sugar target that I need achive? Also I have noticed that some recipes call for lemon juice. Am I suppose to have a specific PH value or range for the product?

[Guest]

Lemon juice contains high amounts of pectin, which is what helps jams and jellies set. Most fruit have pectin, but in varying amounts...some have more than others. The addition of a couple of tablespoons of lemon juice won't change the flavour of your jelly, but will increase pectin levels, enabling setting of your jelly.

To be on the safe side, I add lemon juice to all the jams and jellies I make. It never hurts to have more pectin.