Fermented Fries (Crispy, Tangy, Plant-Based)
These golden chips get their signature lightness and flavour from a short lactic acid fermentation. The result? Crisp outsides, fluffy insides, and a subtle tangy kick that makes them deeply savoury and naturally moreish. They’re fermented, plant-based, and a wonderful example of bringing real food to life—literally!
Takes 3 days 40 minutes
Serves 4
Ingredients
- 1 kg floury potatoes Maris Piper or Rooster work brilliantly
- 1 L 4¼ cups filtered water
- 15 g 1 tbsp sea salt
- Neutral oil for cooking rapeseed, sunflower, or avocado oil
To finish (optional but excellent):
- Flaky sea salt
- Fresh thyme or rosemary
- Cracked black pepper
- Plant-based aioli or fermented hot sauce for dipping
Instructions
Prep the potatoes
- Cut the potatoes (leave the skins on if you can, as this boosts fibre) into chip or French fry shapes, about 1cm thick.
- Rinse well under cold water to remove surface starch.
Ferment the chips (2–3 days)
- In a large jar or fermentation-safe container, dissolve 15g salt into 1L filtered water to make your brine.
- Submerge the raw chips fully in the brine. Weigh them down with a fermentation weight or a clean glass to keep them under the liquid.
- Cover loosely with a lid or cloth and leave to ferment at room temperature for 2–3 days. You should see small bubbles and notice a lightly sour aroma by day 2 or 3. Fermentation begins breaking down the starches, improving digestibility and enhancing flavour, while adding a gentle acidity for extra depth.
Rinse and dry
- After fermentation, drain and rinse the chips well.
- Pat them completely dry with a clean tea towel—this step is crucial for crispness.
Cook the chips
Option 1: Air fry (healthier)
- Toss the chips lightly in 15–30g (1–2 tbsp) neutral oil.
- Air fry at 200°C (392°F) for 12–15 minutes, shaking halfway, until golden and crisp.
Option 2: Oven-bake
- Preheat the oven to 220°C (428°F).
- Spread chips on a parchment-lined tray, drizzle with 30–45g (2–3 tbsp) oil, and toss to coat.
- Bake for 30–35 minutes, turning halfway, until crisp.
Option 3: Shallow fry (for maximum crunch)
- Heat oil in a deep pan to 180°C (356°F).
- Fry the fermented chips in batches for 3–5 minutes until golden.
- Drain on kitchen paper and season straight away.
To finish
- While still hot, toss the chips with flaky sea salt, chopped herbs, or cracked black pepper.
- Serve with your favourite fermented ketchup, hot sauce, or plant-based aioli.
Tips
- Don’t ferment for longer than 3 days or the chips may soften too much.
- For a probiotic twist, serve with sauerkraut or kimchi on the side.
- Save the potato fermentation brine—it’s packed with flavour and can be used to kickstart other ferments!