Slatko and candied fruit, step by step

1. Sugar as a preservative

Sugar slowly replaces the water in the fruit until there is so much that neither mould nor yeast can spoil it.

1. Thick syrup preserves — Slatko is done when the syrup has roughly 65–68 % sugar. Candied fruit has 70–75 %.
2. Sugar goes in slowly — Water leaves the cells and sugar goes in. If you put fruit straight into a strong syrup, it shrivels, hardens and stays hollow in the middle.
3. How to measure — Refractometer: 65 °Brix is 65 % sugar. Without one: a drop in a glass of cold water stays as a ball, or the syrup boils at 105–106 °C (221–223 °F) up to 300 m (1,000 ft) altitude.
4. Hot syrup burns — Syrup boils at 105 °C (221 °F) and above and sticks to the skin. A heavy-based pan, the handle towards the wall, children and animals away from the cooker.

Why: In a syrup of 65 % sugar too little free water is left for germs. But that holds only for a thick syrup, and only once the sugar has got into the fruit, not just around it.

• The refractometer a beekeeper uses to measure water in honey often has a °Brix scale from 58 to 90 as well.
• Syrup isn't tasted with a finger or a spoon from the pan: a drop onto a plate or into water, then wait.

2. Pickling lime without the risk

Lime gives fruit calcium, so watermelon rind and walnuts stay crisp and whole even after long cooking.

1. Food-grade lime only — Slaked lime sold as pickling lime, food-grade calcium hydroxide. Builder's lime can contain impurities and heavy metals.
2. Gloves and goggles — Lime burns skin and eyes, and the dust is dangerous. Work outdoors or by an open window.
3. 15 g per litre — Roughly 15 g of lime per 1 L of cold water, stir and let it settle. A container of glass, enamel or food-grade plastic, because lime attacks aluminium.
4. Three rinses — Soak the fruit in fresh cold water for 1 hour, drain and repeat twice more. Dilute the lime water and pour it down the drain or onto the compost.

Why: Lime water isn't essential, but without it slatko is softer. Lime burns skin and eyes, so handle it carefully, and afterwards it must all be rinsed off.

• Lime in the eye is an emergency: rinse the eye under running water for at least 15 minutes, with the eyelids held open, then see a doctor.
• Keep the bag of lime closed, labelled and away from children, sugar and flour: a white powder is easily mistaken.

3. Green walnut slatko · Locked

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4. Watermelon rind slatko · Locked

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5. Slow candying · Locked

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6. Drying and storage · Locked

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