Introduction

The brewing system shown at right is a home-built machine for making beer.  In this part of the brewing process, various malted grains are mixed with water and the mixture, called �wort�, is held at different temperatures.  Depending on the type of beer being brewed, the wort is raised and held at different temperatures for specific time periods.  This process is called the �mash�.

Various techniques are used to perform the mash.  One technique is to use a Recirculating Infusion Mash (RIM) system. 

The RIM technique forms a grain bed, which is supported on a mesh. 

A pump recirculates the wort through a heater to maintain the pre-determined temperatures. 

The heater is manually controlled by dialing on the required temperature, and allowing a thermostat to control power to a heating element. 

An independent temperature sensor measures the actual temperature, and allows a computer to monitor the actual vs. the expected temperature.