1. Wash and dry the chilis and bell peppers. Remove the green stems from the chili peppers and cut them into (not too small) pieces. If you prefer a milder hot sauce, remove all or at least some of the seeds. Halve the bell peppers and remove the seeds and membranes. Cut the bell peppers into pieces as well. Keep one larger piece intact to serve as a »lid«.

2. Add the chili and bell pepper pieces to a clean preserving glass jar and press them down a bit. Add the larger piece of bell pepper last so it covers everything underneath. Hold the pieces in place using a fermentation weight* or a similar tool.

3. Next, prepare a brine using water and sea salt. The quantity depends on the size of the jar. The solution should contain 2% salt. This means for 1 liter of water you need about 20g (0.7 oz) of sea salt. Once the salt has completely dissolved, pour the brine into the glass jar. The veggies should be fully submerged in the brine. Give the jar a gentle shake to release any trapped air bubbles. Nothing should be floating on the surface – remove any seeds that have risen to the top, for example. Discard any leftover brine or use it, for example, for cooking pasta. Close the glass jar with the lid, but do not tighten it too much. Gases produced during fermentation need a way to escape. If you plan to ferment foods frequently, it might be worth investing in fermentation jars* with special lids designed to allow gas to escape easily without letting air in.

4. Once the glass jar is fully prepared and nothing is floating on the surface of the brine, place it in a corner of the kitchen that stays cool and out of direct sunlight. An ideal temperature range for fermentation is approximately 20–24°C (68–75°F) over a period of 5–10 days. The warmer the environment, the faster the fermentation process proceeds. However, higher temperatures also increase the risk of unwanted bacteria or mold developing. The brine will turn cloudy after a few days, but this is perfectly normal. I usually check the glass jar on day 3 or 4 to ensure everything looks good, removing any bits that may have floated to the surface and could cause issues.

5. Once the chili and bell peppers have fermented sufficiently, and provided no mold or other contaminants have formed, you can proceed to process the peppers. Simply drain the brine, making sure to reserve some of it. Place the drained peppers in a blender and blend/purée until smooth. If the mixture seems too thick or paste-like, add a little of the reserved brine and blend again. Finally, add some white wine vinegar – 1 tablespoon should suffice – and blend once more. Pour the hot sauce into sterilized bottles and store them in the fridge. If you worked clean and no harmful bacteria developed during fermentation, the hot sauce should keep in the refrigerator for up to 6 months.