Most vegetable purees are made by first cooking the vegetable to soften its tissues, break apart the cells, and free their thickening molecules. Some that develop an especially suave smoothness have cell walls rich in soluble pectin, which escapes from the softened wall fragments during pureeing. These vegetables include carrots, cauliflower, and capsicum peppers; as much as 75% of the cell-wall solids in capsicum puree is pectin. Many root and tuber vegetables (though not carrots) contain starch granules, which when cooked absorb much of the water in the vegetable and make it less watery. However, such vegetables are best crushed gently, without breaking open the cells. Thorough pureeing that liberates the gelated starch turns the vegetable into a super-thick potato gravy, gluey and stringy.