Oleo Saccharum (Citrus Oil Sugar for Punch)

Before you start

Oleo saccharum means oiled sugar. You toss citrus peels with sugar and leave them alone, and the sugar slowly draws the fragrant oils out of the peel, forming a glossy, intensely aromatic syrup with no heat at all. It is the traditional foundation of punch and gives flavor that juice alone cannot provide.

Success depends on the peel. Use firm, fragrant lemons, and peel them in wide strips with as little white pith as possible, since pith adds bitterness. Superfine sugar works fastest because it has more surface area. Time does the rest: an hour gives a good result, several hours a great one. Once the oil has been extracted, many punch recipes add citrus juice to dissolve the remaining sugar, making a lemon sherbet that can be measured into a bowl like any syrup.

Ingredients

• 6 lemons — preferably unwaxed; scrub waxed fruit in warm water
• 150 g (¾ cup) superfine sugar — or granulated sugar pulsed briefly in a blender
• 120 ml (4 oz) fresh lemon juice — from the peeled lemons, strained; for sherbet

Method

1. Scrub the lemons and dry them. Using a Y-peeler, remove the zest in long strips, pressing lightly so you take only the yellow layer. Check the underside; if you see thick white pith, shave it off.
2. Put the peels in a bowl with the sugar. Press and twist them with a muddler for about a minute, until you smell lemon strongly and the sugar starts to look damp.
3. Cover the bowl and leave it at room temperature for 2 hours, or refrigerate for up to 12 hours. Stir once or twice. The sugar will dissolve into a shiny, yellow syrup clinging to the peels.
4. Juice the peeled lemons and strain the juice. Pour it over the peels and stir until any remaining sugar crystals dissolve, about 1 minute.
5. Strain out the peels, pressing them to release the last of the syrup. Use the sherbet right away in punch, or chill it until the party.

Tips for success

• Mix citrus: a combination of lemon with a couple of oranges or a grapefruit makes a rounder punch base.
• If you want the oleo alone, without juice, add 30 ml warm water to dissolve the sugar and scrape out every bit of syrup.
• Peel the lemons before you juice them. It is almost impossible to peel a juiced half.

Substitutions

Superfine sugar

Granulated sugar works but takes longer, and some crystals may remain. Demerara adds caramel depth that suits rum or brandy punch.

Lemons

Grapefruit, orange, lime or bergamot all work. Limes give less oil, so use 8 to 10.

Lemon juice

Use warm water instead for a softer, less tart syrup, or a light black tea for a classic punch-house touch.

Variations

Spiced oleo

Add 2 crushed cardamom pods and a broken cinnamon stick to the peels before resting.

Non-alcoholic punch base

Lengthen the sherbet with cold black tea and soda water for a sparkling lemon punch.

Troubleshooting

Very little syrup formed

The peels were too thin, the sugar too coarse, or the rest too short. Muddle again and give it another hour or two.

The punch tastes bitter

Too much pith came off with the zest. Peel more lightly next time; you can soften this batch with a little more sugar.

Sugar remains gritty

Add a splash of warm water or juice and stir until fully dissolved before adding spirits.

Storage

Oleo saccharum without juice keeps up to 1 week in the refrigerator in a sealed jar. Once mixed with fresh juice, refrigerate and use within 2 to 3 days, since the fresh juice flavor fades quickly.