Cleaning In Place (Cip) refers to methods used to clean the interior surfaces of pipes, vessels, and tanks without disassembly and often without manual labor. Before CIP became commonplace in the 1950s, brewing process equipment was often disassembled and the parts cleaned individually by hand. CIP is not unique to the brewing industry; it is applied in all industries that process liquids in closed systems.

Tanks, piping, brewing vessels, and packaging equipment in modern breweries are all closed systems. Frequent cleaning of such equipment is necessary to uphold the required microbiological and chemical quality of the beer produced through it. Consequently, cleaning and sanitizing of the brewing equipment must take place in a way that allows the equipment to remain closed and personnel to be kept safely isolated from oftentimes very hot chemical cleaning solutions. In large modern breweries the cleaning processes are so comprehensive and elaborate that automation is often necessary for sufficient control of costs, energy and time management, and consistency. Thus, the concept of CIP in the modern brewing world is not just a convenience; it is in many cases a necessity.

CIP cleaning of vessels takes place by means of liquid dispersal devices mounted inside the vessels as part of the construction. These are normally either static sprayballs or different sorts of rotary jets. These devices, using liquid pressure, direct sprays of cleaning solution toward every part of the internal surface of the vessel. The cleaning solution, often an alkaline detergent or acid solution at elevated temperatures, is then repeatedly circulated through the vessel in a manner not dissimilar to that of a dishwasher. The dispersal device may be designed to gently flow cleaning solution over all interior surfaces or it may be a high-impact jet that uses mechanical as well as chemical energy to remove soils. Piping, pumps, valves, filling machines, and other pieces of processing equipment that do not have internal cleaning devices are CIP cleaned by circulating cleaning solution through the parts that contact beer or wort.

The central unit in any CIP cleaning process is the CIP station or CIP unit. This consists of a number of vessels for cleaning solutions plate heat exchangers for ensuring the correct temperature of the solutions and pumps for circulation of cleaning solutions at the required pressure, and flow rates through the route/equipment to be cleaned. Such units can be automated to any extent desired. In smaller breweries and brewpubs, the same task is often accomplished without a dedicated CIP station, so each brewery devises its own effective cleaning method using pumps, hoses, and other equipment on hand. A corollary to CIP is sterilization in place, which uses similar methods, often with a sterilizing chemical solution, to sterilize interior surfaces of vessels and process equipment.