Sauces are thickened liquids that complement foods by adding color, shine, flavor and richness. They contribute visual appeal and moisture. All sauces are thickened using starches, purees, eggs or emulsions. Common thickening methods include a roux made of equal parts flour and fat cooked to different shades, slurries of starch in cold liquid, and pureed fruits/veggies. Mothersauces like bechamel, veloute, demi-glace and hollandaise are base sauces that derivative sauces are made from.