What type of brush hair is best for watercolour?

Natural hair

Natural hair brushes are a good choice for working in watercolour because they tend to be soft and flexible. Natural hair brushes come in different varieties.

Sable brushes maintain a perfect point, allowing for great control, and are excellent for precision marks. Sable hair strands are conical, springy, and covered in tiny scales. The combination of the three factors increases the brush’s surface area and allows it to soak up a lot of colour. Sable brushes are very high quality, with the best – such as Winsor & Newton Series 7 brushes – handmade from the tip of the tail of the Siberian kolinsky sable.
Squirrel brushes carry colour very well because they can hold a lot of water. They are very good as mop and wash brushes, as they do not point as well as sable.
Goat brushes also have a good colour carrying capacity but tend not to release the colour as well as squirrel or sable, and have no point.
Camel is a term used for an array of miscellaneous low quality natural hair brushes.

Synthetic

If you prefer an alternative to natural hair or are on a budget, then it is worth considering synthetic brushes. Driven by innovation and our unique brush-making expertise, our synthetic brushes perform at a professional level. They can be soft or stiff; the soft brushes work well with watercolour, while the stiff brushes work best with oils. Synthetic brushes often have an excellent point and can carry colour very well. Winsor & Newton offers a wide range of synthetic brushes including Professional Watercolour Synthetic Sable brush, Monarch Brushes and Cotman Brushes.