The other heat source
When planning a brew system, the big decision used to be direct fire or steam. But, for brewers with systems up to 10 barrels, there is a third viable option for firing a brewhouse. Increasingly, brewers are using electric elements to heat their strike, sparge water, and boil their wort.
Electric brewing is not new – brewers have been been using electricity to power their brewhouses for more than 20 years. The original New Belgium brewkettle used three long ceramic sheathed elements for wort boiling. What has changed is the degree of precision temperature control brewers can achieve with modern electric elements and control systems.
HOW DOES IT WORK?
In electric brewing the heat is applied internally, rather than externally, as is the case with direct-fire burners or steam jackets. The heat source is electric elements in stainless steel sheathes that are inserted in the tank – hot liquor tank and/or brew kettle — through triclover ports in the side of the tank. Because the elements are immersed in the liquid, nearly 100 percent of the energy applied to the elements is transferred to heating the water or wort.
In the simplest of systems, those elements are connected to on/off switches and the amount of heat applied is controlled by turning individual elements on and off. However, to take full advantage of the precision and repeatability that electric brewing offers, brewers often add a control panel to be able control the percentage of output of each element and obtain temperature control to within 1 degree Fahrenheit.
CONTROL SYSTEM
The precision temperature control is most useful in hitting and maintaining mash temperatures in either single infusion or step-mash regimens. Most electric brew systems employ either recirculating mash infusion systems (RIMS) or heat exchange recirculating mash systems (HERMS). In a RIMS system, wort is recirculated by a pump over a heating element within a tube. The element heats the wort to either maintain or raise the temperature, depending on the brewer’s desire. In a HERMS system, the wort is circulated through a coil inside the hot liquor tank and the temperature is maintained or raised by controlling the temperature of the water in the hot liquor tank.
The control system includes temperature probes that are inserted into thermo-wells in the tanks, proportional-integral-derivative controllers (PIDs) to set the target temperature and solid state relays (SSRs) to control the percentage output of each element. The control panel can also be used to control the variable speed wort pumps that circulate the wort trough a RIMS or HERMS system. In larger HERMS systems, there may also be a water pump that recirculates the water in the hot liquor tank to avoid stratification.
THE PROS OF PRECISE TEMPERATURE CONTROL
Temperature control also comes into play in the brewkettle to help avoid boilovers and also control the rate of evaporation. By knowing the amount of energy needed to reach a boil and attain the desired amount of evaporation (usually 7-10 percent per hour), brewers can program their control panel to hit their targets batch after batch.
The amount of heat applied is determined by the number and wattage of the elements used. The standard wattages of brewing elements are 5,500 watts and 10,000 watts. Because the elements are ultra-low watt density, they are configured to produce less heat per square inch to eliminate the possibility of scorching wort when used properly. Depending on the batch size, between one and six elements are used. Most brewers recommend having at least 12 kilowatts of heating capability for a one-barrel batch size and 60 KW for a 7-barrel.