Wash the yuzu well and separate the yuzu into 3 parts; the peel, seeds and the pulp (including the fruit juice and membrane). The only part you won't be using are the seeds and the stem.
Julienne the yuzu peel, including the pith. Finely cut the fruit pulp.
Boil the julienned peels for 5 minutes in plenty of hot water, drain well and soak in a bowl of cold water.
Change the water 2 to 3 times, gently wash the peels, and let the peels soak in the water overnight. Drain the water the next day.
Add the peels, chopped fruit pulp, sugar, and water in a pot, and simmer over medium heat. After simmering until it's reduced by less than 1/3, and the mixture has thickened, the jam is done. This will take about 45 minutes.
Store in a sterilized jar.
Story Behind this Recipe
I make jam every year with yuzu picked from my garden in an attempt to use the whole fruit.
■ The only part you won't be using are the seeds and stem. ■ When chilled, the jam will thicken more, so when it starts to thicken slightly, remove from heat and it's done. ■ Since sugar burns easily, be sure to mix often with a wooden spatula while simmering. ■ Carefully skim off the scum while simmering the yuzu mixture.