saturated solution

A saturated solution is one that has dissolved all the solute it can hold at a given temperature — any more added just settles at the bottom instead of dissolving.

• The moment undissolved salt starts collecting at the bottom of a glass, no matter how much you stir, that's the signal the solution has become saturated.
• Saturation isn't a fixed, permanent state — heating a saturated solution can dissolve the leftover solute again, since solubility generally rises with temperature, turning it unsaturated once more.
• Because saturation is temperature-specific, the same solution can be saturated at 20°C but unsaturated at 70°C, holding much more dissolved solute once warmed.
• Saturated solutions come up outside chemistry too — cooking sugar syrups or brines to just the right concentration usually means deliberately pushing a solution close to saturation.