Development of an on-line specific gravity meter for the craft brewing industry

An inexpensive meter for the continuous measurement of specific gravity in a microbrewing operation was described. The device was based on measuring the change in force acting on a body immersed in the fermentation broth. Testing was performed at the Picaroons Brewing Co. (Fredericton, NB, Canada), on a production run of Picaroons Red Ale. The signal from this device was shown to correlate with the specific gravity of the liquid. A linear response was observed between the output of the meter and the specific gravity estimate obtained using a hydrometer. Although some filtering of the data was required, no significant lag time was imposed.