Greaseproof paper is paper that is impermeable to oil or grease, and is normally used in cooking or food packaging. It is usually produced by refining the paper stock [further explanation needed] and thus creating a sheet with very low porosity. This is then passed between hard pressure rollers (supercalendered) to further increase the density, creating a paper called glassine. The glassine is treated with starches, alginates or carboxymethyl cellulose (CMC) in a size press to fill pores or treat the paper chemically to make it fat repellent. Basis weights are usually 30–50 g/m2.[1]
