Chenpi (aged tangerine peel)

Fill the sink with water, dissolve the salt and baking soda, and soak the tangerines 30 minutes.

Rub gently with a clean sponge, drain, refill and rinse thoroughly.

Dry under a fan a couple of hours, until no moisture is left on the surface.

With the tip of a chef's knife, score each peel into 3 even sections, stopping half an inch short of the stem end so the peel stays joined (4 sections is easier for a beginner, but fewer cuts damage fewer oil glands).

Open the peel like a flower with a small spoon rather than fingers, which bend or bruise the skin, and remove the fruit.

Lay the peels on a tray or sheet in direct sunlight; check after three to five hours, until slightly soft and wilted, then gently turn each inside out.

Flip midday for even drying; bring indoors before dark every day, loosely covered (not airtight) on the countertop, since overnight dew can ruin them.

Continue sun drying 3 to 5 days, about 4 to 6 hours each day, until completely dry: two pieces tapped together sound dry and crispy.

First year: store in a clean plastic bag, not fully sealed, in a dark, cool, dry place; sun-dry 3 times a year for 1 to 2 days each time to prevent mold and insects.

After the first year, sun-dry once a year for 1 to 2 days. After 3 years they are aged tangerine peel.

Move to an airtight container, opened a few times a year for air exchange; past 3 years yearly sun drying is no longer needed, but sun-dry again whenever the peels feel soft.