I've been making jam for the last 30+ years and have never had to add
anything other than ordinary sugar.
I have made Black currant, blackberry, raspberry, strawberry, and
loganberry jam as well as apple jelly.
Just use good firm fruit .
Must say I have never tried making Jam in the microwave.

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David Hill
Abacus nurseries
www.abacus-nurseries.co.uk