Open the wine. Pour out 1/2 cup to enjoy while you carry on with the recipe. (This is not greed; a bit has to come out or the bottle with overflow when you add the other ingredients.)
Shave the zest from the orange with a vegetable peeler
. Remove every trace of bitter
from the back with a sharp knife. Poke the orange zest
into the bottle of wine. Funnel in the sugar. Drop in the coriander
seeds, if using. Recork the bottle. Turn it upside down and right side up a few times until the sugar
has dissolved. Refrigerate for 1 week, giving the wine a shake once a day.
into a carafe
and serve well-chilled as an aperitif.