The effect of air temperature, velocity and visual lean (VL) composition on the tempering times of frozen boneless beef blocks

The results show that single stage air tempering of even single blocks within their cartons needs to be a long process. In air at 3 °C and 5 ms−1, blocks of 50% VL rose to deep temperatures of −10 °C and −3 °C after 4.0 and 22.5 h, respectively, while with 100% VL 4.6 and 27.3 h were required. Under these conditions, the surface layers of the meat would have spent many hours in a thawed condition that would be detrimental to both drip and optimal processing. Using lower temperatures avoids thawing and at the same time produces an optimum temperature difference for subsequent processing. However, tempering times are substantially extended. For example, times to the above temperatures using air at −1 °C and 5 ms−1 were 4.8 and 37.5 h for 50% VL and 5.1 and 44.5 h for 100% VL.