Stabilization is a series of post-fermentation and maturation operations that are intended to protect the stability of wine. They're divided into two general categories. The first is microbiological stability, which is intended to remove unwanted effects of bacteria and yeasts (such as unwanted secondary fermentation brought on by yeast remaining in the wine). The second is physical and chemical stability, which protects wine from excessive tannins, browning phenolic compounds, and unstable proteins. Physical and chemical stability procedures include fining to remove proteins, and cold stabilization to remove tartrate crystals in white wines.