What is equilibrium relative humidity or ERH ?
Equilibrium relative humidity or ERH refers to the interstitial or inter-kernel air relative humidity in a stored grain mass. The ERH is the air relative humidity that grain will reach and sustain in the void space between kernels when stored for a long period of time. Scientists measure the interstitial air temperature and humidity, then accurately predict the moisture content of grain in a given location in a storage. ERH is correlated to water activity of grain or other durable commodities; water activity relates to mold activity limits of the product. At a given grain temperature and ERH grain can be safely stored without molding this point is the threshold ERH condition for that grain type.
