size of its particles The smaller the particles, the less noticeable they are to the tongue, and the smoother the texture Also, the smaller the particles are, the more of them there are to do the obstructing and the more surface area they have to take up a layer of water molecules: and so the thicker the consistency they produce Suspensions are always opaque, because the solid particles are large enough to block the passage of light rays and either absorb them or bounce them back toward their source Because the particles and water are very different materials, suspensions tend to settle and separate into thin fluid and concentrated particles Cooks work to prevent separation by reducing the volume of the continuous phase (draining off or boiling away excess water), or by augmenting the dispersed phase (adding starch or other long molecules or fat droplets) Nut butters and chocolate are suspensions of solid seed particles not in water, but in oils and fats Thickening a liquid with food particles In a suspension, microscopic chunks of plant or animal tissue are suspended in liquid, and give the impression of thickness by interfering with the liquid’s flow Clear Dispersions and Gels: Thickening with Molecules A single microscopic fragment of a tomato cell wall or muscle fiber is built up of many thousands of submicroscopic molecules Not all of the large molecules in those fragments can be teased away from each other so that they are individually dispersed in water But those that can be extracted in this way — starch, pectins, such proteins as gelatin — are very useful thickening agents Because single molecules .. .and fats Thickening a liquid with food particles In a suspension, microscopic chunks of plant or animal tissue are suspended in liquid, and give the impression of thickness by interfering... give the impression of thickness by interfering with the liquid’s flow Clear Dispersions and Gels: Thickening with Molecules A single microscopic fragment of a tomato cell wall or muscle fiber is built up of many thousands of submicroscopic molecules... is built up of many thousands of submicroscopic molecules Not all of the large molecules in those fragments can be teased away from each other so that they are individually dispersed in water But those that