Preserving Chillies in Oil

Chilli-infused oil is one of the great condiments — but it carries a genuine food safety risk that deserves clear explanation before you start.

The botulism warning

Clostridium botulinum thrives in low-oxygen, room-temperature, moist environments. A jar of oil with garlic and fresh chilli is exactly this. Botulism is rare but potentially fatal, and the toxin has no smell or taste.

Rules to avoid risk:

1. Use dried chillies, not fresh for oils stored at room temperature.
2. Never include fresh garlic in room-temperature oil. Dried garlic powder is safe.
3. If using fresh ingredients, refrigerate and use within 2 weeks.
4. Acidify fresh ingredients (soak in vinegar for 10 minutes) before adding to oil — this reduces but doesn't eliminate risk.

Safe method: dried chilli infusion

1. Ensure dried chillies have no moisture content.
2. Heat oil to 120°C, add dried chillies, reduce to lowest heat for 20 minutes.
3. Cool, strain, bottle in sterilised glass. Seal.
4. Store in a cool, dark place for up to 3 months, or refrigerate for 6 months.

Flavour variations

• Smoked: Use smoked dried chillies (chipotle, smoked cayenne).
• Aromatic: Add dried bay leaf, whole peppercorns, dried rosemary.
• Asian-style: Use chilli flakes with Szechuan pepper and sesame oil added after cooling.