What To Do With Mandarin Peel

Mandarin peel has more uses than most people expect. The outer layer holds essential oils that are useful in cooking, cleaning, and the garden. The white pith underneath is more limited: it is bitter and does not dissolve well, so most peel preparations either remove it or minimise it.

Mandarin zest

Mandarin zest is the grated outer layer of the skin. It carries a high concentration of d-limonene, the aromatic compound that gives mandarins their distinctive fragrance.

Use fresh zest:

Stirred into butter or cream cheese
Folded into cake batters or muffin mixes
Mixed into salad dressings and vinaigrettes
Added to a marinade for chicken or pork

Grate zest before peeling the fruit. Use a fine Microplane-style grater and work only the coloured outer layer. Stop when the white pith becomes visible. A medium mandarin gives roughly one teaspoon of zest.

For mandarin cakes and baked goods that call for zest, see mandarin cakes.

Candied mandarin peel

Candied peel is made by cooking strips of peel slowly in sugar syrup. The sugar replaces moisture in the peel and preserves the flavour.

The main preparation step is blanching. Mandarin peel is more bitter than orange peel because the pith is thinner but more intensely flavoured. Blanching the strips two to three times in fresh boiling water each time reduces this before you begin the candying process.

Candied mandarin peel keeps for several weeks in an airtight container and can be used:

Dipped in dark chocolate as a confection
Chopped through Christmas cake or fruit loaf
Added to biscotti
Stirred into mandarin marmalade for texture

For a full method, see candied mandarin peel.

Drying mandarin peel

Dried mandarin peel has a long history in Chinese cooking, where aged dried peel (chen pi) is considered a spice in its own right. Australian home cooks have a simpler version: peel dried in a low oven or on a rack, then stored in a jar.

To dry mandarin peel at home:

Peel mandarins in wide strips.
If time allows, scrape away most of the white pith with a spoon. This reduces bitterness in the dried product.
Lay flat on a wire rack.
Dry in an oven at 60 to 70 degrees Celsius for two to three hours, until the peel is fully dry and slightly brittle.
Alternatively, leave on a rack at room temperature in a dry spot for three to five days.

Dried peel can be used whole in broths and slow-cooked dishes, crumbled into spice mixes, or added to herbal teas. Ground dried peel makes a flavourful addition to dry rubs for duck or pork.

For syrups and liqueurs that use mandarin flavour, see mandarin syrups.

Mandarin peel for cleaning

The essential oils in mandarin peel have mild degreasing and antimicrobial properties. A basic citrus surface cleaner can be made at home with minimal effort.

Simple mandarin peel cleaner:

Pack a jar loosely with mandarin peels.
Cover with white vinegar.
Seal and leave for two weeks.
Strain the liquid into a spray bottle. Dilute with water one part infusion to one part water.

Use on benchtops, stovetops, and sinks. The vinegar does the cleaning work; the mandarin peel leaves a pleasant scent and adds some additional grease-cutting capacity.

Do not use on natural stone surfaces like marble or granite. The acidity in the vinegar will etch the stone over time.

Mandarin peel in compost

Mandarin peel composts readily in a healthy, active compost bin. The concern sometimes raised about citrus peel in compost (that it kills worms or inhibits decomposition) is mostly overstated for a well-balanced heap. A few handfuls of peel added regularly causes no problems.

Where large volumes become an issue is in a slow, wet heap. A pile that receives kilos of fresh citrus peel without balancing dry carbon material (cardboard, straw, dry leaves) can become acidic and slow.

Best practice:

Break or chop peel into smaller pieces rather than throwing in whole strips. Surface area speeds breakdown.
Mix with carbon-rich materials.
Do not add peel to a worm farm in large amounts. Worms are sensitive to the citrus oils in high concentration.

Mandarin peel as a garden deterrent

Cats and some dogs avoid the smell of citrus. Scattered mandarin peel around garden beds can deter them from digging or using a bed as a toilet. The effect is temporary: peel dries and loses its scent within a day or two, especially in warm weather. Fresh peel needs to be replaced regularly to maintain the deterrent effect.

Place peel around the base of plants or along garden edges. This also adds small amounts of organic matter to the soil as it breaks down.

Mandarin peel for the fireplace

Dried mandarin peel burns slowly and gives off a pleasant aromatic smoke. It works well as a natural fire starter added on top of kindling, or as a slow-burning aromatic layer once a fire is established.

Peel must be fully dried before use. Fresh or even slightly damp peel will smoulder and produce more smoke than flame. Use the oven-drying method above if you want peel ready for the fireplace within a day.

This is a practical winter use during mandarin season, when peel is plentiful.

What not to do with mandarin peel

Do not put whole mandarin peels down a kitchen waste disposal. Citrus peel is fibrous and can bind around the blades or cause blockages in pipes. Small amounts of finely chopped peel are generally fine, but whole strips or large pieces are not.

Do not feed mandarin peel to dogs. The essential oils in citrus peel are toxic to dogs and can cause digestive upset, central nervous system symptoms, and in large amounts, more serious reactions. Fruit flesh in small amounts is generally tolerated, but peel is a different matter. See can dogs eat mandarins for full guidance.

Do not add peel to a slow cooker in large quantities without reducing it first. The oils and pith can turn a dish very bitter over a long, low cook.

For more recipe ideas using the whole mandarin, including zest-forward baked goods and preserves, see mandarin recipes. For marmalade that uses peel as a key ingredient, see mandarin marmalades.