Making marshmallows from syrups of unknown concentration

[TylerK]

Every year around this time I candy a bunch of orange slices for use in Christmas treats, and afterwards I'm left with a bunch of very tasty orange syrup.  Similarly, after making a bunch of cherry cordials with amarena cherries I'm left with a bunch of cherry syrup. Inevitably, a lot of it ends up getting tossed because there's just too much of it to use in other applications.  This year I'd like to try my hand at turning it into some orange marmalade and cherry flavoured marshmallows, but it's hard to match it to a recipe when I'm unsure what the sugar concentration in my syrup is.    

 

My question is, do I need to buy a refractometer calculate the amount of sugar I have there or is there another way to approach this?  Maybe estimating quantities by doing an initial cook down to soft ball stage and going by volume?  

 

Any suggestions?

[jmacnaughtan]

Try cooking it to 105°C and weighing it, then doing the same with a batch of normal sugar + water.  You'll be able to find out how much sugar you're dealing with by comparing the weight of the normal syrup with the starting weight of the sugar, and calculating your fruit syrups from there.

[Shalmanese]

Regardless of the starting concentration of the syrup, if you bring it up to a boiling point of 235 - 240F, it will reach the soft ball stage which is 85% sugar.

As for final volume, if the original syrup is liquid at room temperature, it's probably somewhere between a 1:1 and a 2:1 syrup which means you're evaporating about 20 - 30% of the water to get to softball stage. So take whatever existing marshmallow recipe you have and add 20% more syrup than the combined weight of sugar/water in the recipe and you should be roughly in the ballpark.

[TylerK]

Thanks for the suggestions.  Gives me a good place to start.  The consistency of the orange syrup is closer to honey, but it sounds like reducing them both down to known concentrations based on temperature is the way to go.  

[Shalmanese]

Thanks for the suggestions.  Gives me a good place to start.  The consistency of the orange syrup is closer to honey, but it sounds like reducing them both down to known concentrations based on temperature is the way to go.

Are you candying in pure sugar or a sugar/corn syrup mixture? If it's sugar/corn syrup, you're able to get to higher concentrations while keeping in liquid, which sounds like what you have. If so, then I'd do a straight 1:1 sub in a marshmallow recipe.

[TylerK]

I haven't been adding any corn syrup.glucose to the candying oranges.  Given the acid in the oranges and the heat applied during the candying process though, I wouldn't be surprised if there was a fair amount of invert sugar in the final orange syrup.

[AAQuesada]

Just to bring up another issue, most likely there is some pectin now in that syrup for candying oranges. How will that change boiling up to softball? 

[TylerK]

Not a clue, but thanks for raising the point.  I can see it affecting the texture of the marshmallows.  May have to adjust the quantity of the gelatin down a touch?

[minas6907]

I personally wouldn't mess with the amount of gelatin until you try it first.

This is interesting actually, I want to try this. I have a hefty quantity of 75% syrup left over from candying plums, when I get a chance im going to give this a try.