What the heat is doing
Capsaicin and the aromatic compounds in dried chilli are fat-soluble, so hot oil extracts them efficiently. It also toasts the chilli, developing a deeper, rounder flavour than the raw flakes have.
The window is narrow. Below a certain temperature little is extracted and the oil stays pale and thin-tasting. Above it, the chilli scorches almost instantly and the whole batch becomes acrid.
Rather than chasing a number, the practical approach is to heat the oil with aromatics until they sizzle and colour, let it cool slightly, and then pour it over the chilli in stages — watching what happens and stopping if it darkens too fast.
The method
Infuse the oil first, then pour it over the chilli.
- Put the chilli flakes in a heatproof bowl with a pinch of salt. Coarse Korean gochugaru or Sichuan flakes give colour without ferocious heat; ordinary crushed chillies are hotter and duller.
- Warm a neutral oil in a pan with aromatics — sliced ginger, garlic, spring onion, star anise, cinnamon, bay, Sichuan peppercorns.
- Heat gently until the aromatics sizzle steadily and begin to colour. Do not let them blacken. This is an infusion, not a fry.
- Strain the aromatics out and let the oil stand off the heat for a minute or two.
- Pour a small amount over the chilli first. It should sizzle vigorously and smell toasty, not acrid. If it darkens instantly, let the oil cool further.
- Pour the rest over, stir, and let it cool completely. It improves overnight.
- For a crisp chilli oil, stir in fried shallots, fried garlic, toasted sesame seeds and a little sugar and soy once it is cool.
Variations and uses
- Sichuan style, with Sichuan peppercorns for the numbing quality alongside the heat.
- Chilli crisp, with fried shallot and garlic stirred through for crunch. Add them once the oil has cooled or they go soft.
- With fermented black beans, which adds savouriness.
- With toasted sesame seeds and a splash of sesame oil, added cold.
- On noodles, dumplings, rice or eggs, which is where most of it goes.
- Over roasted vegetables or a bowl of soup.
- In a dressing, with black vinegar and soy.
- Storage — chilli oil containing fresh aromatics like garlic raises food-safety questions, and the Food Standards Agency is the authority on infused oils.
Choices
- Chilli
- Coarse Korean or Sichuan flakes give colour and moderate heat. Fine ordinary chilli powder burns more easily.
- Oil
- A neutral oil with reasonable heat tolerance — groundnut, rapeseed or sunflower.
- Aromatics
- Strain them out before pouring, or they burn in the residual heat.
- Sediment
- The chilli sits at the bottom and is the best part. Stir before using.
- Time
- It is better the next day and better still after a week.
Common questions
Why is my chilli oil bitter?
The oil was too hot and the chilli scorched. Let it cool a little and test with a small amount first.
Why does it taste raw?
The oil was not hot enough to extract or toast. It should sizzle vigorously when it hits the chilli.
Which chilli flakes?
Coarse Korean or Sichuan flakes for colour and manageable heat. Fine powder burns easily.
When do I add the crispy bits?
Once the oil has cooled, or they go soft immediately.
How should I store it?
Infused oils containing fresh garlic or aromatics raise food-safety questions. Follow Food Standards Agency guidance.
Try this next
- Chilli the varieties and their heat
- Sesame oil the finishing addition
- How to make pickled chillies the other way to preserve a glut
- Burnt garlic the failure mode to avoid