How to make preserved stem ginger:
It’s quite easy to make your own preserved stem ginger for the ginger Negroni fizz mix. You’ll need fresh, young ginger as the older stuff can be a bit woody.
Freeze around 600g of ginger overnight then peel it while frozen with a paring knife.
Cut the ginger into 2cm chunks and place in a saucepan. Cover with water, bring to a boil then simmer until tender (about 40 minutes; pierce the ginger with a sharp knife to test).
Remove ginger from saucepan, leaving behind 3 cups of ginger water (discard any extra).
Bring ginger water to a boil with 3 cups sugar. Return ginger to pan and simmer for another
15 minutes then pour into sterilised jars. Seal while hot and store in the pantry (the ginger will keep for up to a year).
Refrigerate once opened.