Todays natural bristle mainly comes from China, where there are still older breeds of the domestic hog. The bristle is obtained from the back and neck. Particularly long bristles are becoming rarer in the meantime, even in China, and prices are rising as a result. Modern European hog breeds however only grow a few bristles which are of relatively low quality. This is why they can no longer contribute to the production of brushes.
While fine hair ( squirrel hair, red marten, etc.) has one fine hair tip, natural bristle splits into two, sometimes three tips. These tips are called flags and give brushes made of natural bristle their excellent paint absorption. Natural bristles come in a wide range of colors. There is dun (half white) bristles, white and extra white, but also bristles in natural black. White bristles are usually bleached during further processing. The highest quality natural bristle is Chunking Bristle which comes from the region around the Chinese city of Chungking.
When cared for properly, brushes made from natural bristles can last a very long time. A nice feature of natural bristle is that it ages well and becomes softer and more responsive over time. Brushes with natural bristles are best for painting with pastose paints such as oil or acrylic.