Illustration of finished roast potato chunks with extra crisp craggy crusts on a baking tray
From the Sapidus kitchen

Extra-crisp roast potatoes with bicarbonate of soda

Parboil potatoes with a little bicarbonate of soda, steam-dry them and shake to roughen their surfaces. In the oven, the outer layer becomes a golden crust around a soft centre.

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Home-tested. This recipe has been tested in the Sapidus kitchen.1002

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Extra-crisp roast potatoes with bicarbonate of soda

4 people · About 65–80 minutes

Equipment: Roomy saucepan, colander, lidded bowl and baking tray

Quantities follow your selection; time and temperature do not scale automatically.

Ingredients

Potatoes and roasting

  • 1,000 g peeled potatoes, preferably a floury variety such as Kerrs Pink
  • 4 tbsp olive oil
  • ¼ tsp ground black pepper
  • ½ tsp dried rosemary or thyme, optional
  • Fine salt to adjust after roasting; taste first

Parboiling – measure according to the water

  • Enough water to cover the potatoes generously; about 2 litres for 1 kg potatoes in a suitable saucepan
  • Bicarbonate of soda: ¼ level tsp per litre of water (½ tsp for 2 litres). Use bicarbonate of soda, not baking powder.
  • Fine salt: 8 g per litre of water (16 g for 2 litres). Most is discarded with the cooking water.

Allergens: No declarable allergens in the basic recipe.

Method

  1. Heat the oven and cut the potatoes

    Set the oven to 230 °C conventional, or 200 °C fan. Peel the potatoes and cut into even pieces about 4–5 cm across. Small pieces break up more easily during parboiling.

  2. Measure water, bicarbonate of soda and salt

    Measure enough water into a roomy saucepan to cover the potatoes generously. Add ¼ level tsp bicarbonate of soda and 8 g fine salt per litre. Bring to the boil and carefully add the potatoes. The bicarbonate amount depends on litres of water and therefore does not automatically scale with the number of people.

  3. Parboil gently

    Simmer for about 8–12 minutes from when the water returns to a simmer. The edges should soften and begin to crumble, while a knife meets some resistance in the centre. Start checking after 6–8 minutes, particularly with floury potatoes. Stop before the pieces fall apart.

  4. Steam-dry and roughen

    Drain into a colander and let the potatoes steam-dry for 3–5 minutes. Transfer to a roomy bowl with the olive oil. Put on the lid and shake gently a few times, or turn with a large spoon, until a thin, rough layer forms on the surface. Do not shake them into mash.

  5. Roast with plenty of space

    Spread in a single layer on a roomy baking tray, leaving space between pieces. Roast for 20 minutes without moving them. Turn carefully and roast for another 20–30 minutes. Add pepper and any dried herbs for the last 10 minutes. The potatoes should be golden and crisp outside and completely tender inside.

  6. Season and serve immediately

    Taste a potato before adding any fine salt. Serve immediately and avoid a lid or tightly wrapped foil, which softens the crust.

Quantity4 people · side dishApproximate timeAbout 65–80 minutesEquipmentRoomy saucepan, colander, lidded bowl and baking tray
About portions and timing

Cuisine: International

Estimated timing: about 15 min preparation · about 55 min cooking · about 5 min resting. These times are estimates for the basic method and have not been measured in the kitchen. Follow the method and any time ranges above.

Tick ingredients as you prepare them and steps as you finish them.

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Step by step

Method

  1. Set the oven to 230 °C conventional, or 200 °C fan. Peel the potatoes and cut into even pieces about 4–5 cm across. Small pieces break up more easily during parboiling.

  2. Measure enough water into a roomy saucepan to cover the potatoes generously. Add ¼ level tsp bicarbonate of soda and 8 g fine salt per litre. Bring to the boil and carefully add the potatoes. The bicarbonate amount depends on litres of water and therefore does not automatically scale with the number of people.

  3. Simmer for about 8–12 minutes from when the water returns to a simmer. The edges should soften and begin to crumble, while a knife meets some resistance in the centre. Start checking after 6–8 minutes, particularly with floury potatoes. Stop before the pieces fall apart.

  4. Drain into a colander and let the potatoes steam-dry for 3–5 minutes. Transfer to a roomy bowl with the olive oil. Put on the lid and shake gently a few times, or turn with a large spoon, until a thin, rough layer forms on the surface. Do not shake them into mash.

  5. Spread in a single layer on a roomy baking tray, leaving space between pieces. Roast for 20 minutes without moving them. Turn carefully and roast for another 20–30 minutes. Add pepper and any dried herbs for the last 10 minutes. The potatoes should be golden and crisp outside and completely tender inside.

  6. Taste a potato before adding any fine salt. Serve immediately and avoid a lid or tightly wrapped foil, which softens the crust.

Get to know the spices in this dish

About this version

Home-tested in the Sapidus kitchen. Quantities are for a side dish. Times are approximate; check tenderness and browning.

Details that make a difference

Good to know before you cook

What does bicarbonate of soda do?

Bicarbonate makes the cooking water more alkaline, helping the outside of the potato break down. Roughen that layer and dry it in the oven, and you have more surface to turn crisp. Use just a little. Too much can leave an off-flavour and make the potatoes fall apart.

Let the potato determine parboiling time

Variety, storage and piece size affect timing. Look for soft, crumbling edges and a centre that still holds the piece together. Mandelpotet can break up quickly; Kerrs Pink or a moderately floury potato is easier to handle.

Do not crowd the tray

For a large batch, use several trays and swap their positions in a fan oven. Space and dry surfaces are crucial for the crust.

How this differs from ordinary wedges

Ordinary potato wedges go into the oven raw. Here you parboil with bicarbonate and shake them gently, giving them a rougher surface and a thicker crust. A little more work, and crisper potatoes.

Sources and further reading

Sources were compiled with AI assistance.