Definition - What does Potash mean?
Potash is also known as caustic potash or potassium hydroxide (KOH). In the winery, it is dissolved in water and utilized mainly as a cleaning agent. By rinsing with potash, biofilms of yeasts and bacteria can be removed. Compared to other cleaning agents, it is environmentally friendly, however, its handling must be done with care, as it can be corrosive.
WineFrog explains Potash
Potash is a cleaning agent used widely in wineries as a combatant against unwanted bacteria and yeast cells.
Following the use of a detergent to clean the wine vessels, the tanks are rinsed with water. To make sure that all microbial life is eliminated, a wash with potash, sometimes called potassium hydroxide, is used.
A mild solution of potash is mixed with water and used to rinse the inside of stainless steel tanks. Winery equipment is also cleaned with potash including any hoses, valves and pump-over devices.