Chili sauce is a condiment made from chili peppers and is a common condiment on the dining table. It's most prevalent in Hunan province and comes in two types: oil-based and water-based. Oil-based chili sauce is made with sesame oil and chili peppers, resulting in a bright red color with a layer of sesame oil on top, and it's easy to preserve.

Water-based chili sauce is made with water and chili peppers, also resulting in a bright red color. Garlic, ginger, sugar, and salt are added, allowing for long-term preservation and a more delicious flavor.

Different regions have their own regional variations of chili sauce. Generally, when making chili sauce at home, you would first stir-fry chili peppers in a pan until fragrant (without oil), then grind them into a powder (the finer the better, you can chop them with a knife). You would also add ground Sichuan peppercorns (cooked in a non-stick pan until fragrant, then ground into a powder), and garlic (the amount depends on the amount of chili peppers and personal preference). Add the above seasonings, garlic and vinegar to the pot last, then add oil (the amount of oil depends on the amount of chili peppers, just enough to cover the peppers). You can also add sesame oil directly, but it's better to heat it first. After the oil cools down, add it to the chili peppers, then stir. Add the garlic and vinegar, mix well, and then put it in a glass jar. Use it as a seasoning for cold dishes, noodles, and stir-fries.