Heat transfer data from measurements covering 15 Roberts evaporator vessels at 3 mills (82 data sets total) is presented. Heat transfer coefficient (HTC) is plotted against brix, temperature, temperature difference and viscosity respectively. It is shown that the influence of on HTC cannot be deduced from this type of data. The pronounced difference in operating conditions between last effect and all earlier effects, due to viscosity levels which are orders of magnitude higher in the last effect, is highlighted . HTC values from second to penultimate affect nearly all fell into the range of 1,8 to 3,5 kW ,with no pronounced dependence on effect number. It is shown that very high last vapor vacuum levels are detrimental to evaporation evaporation capacity and optimum last vapour saturation temperature is in the range 55 to 60°C. a heating surface distribution wherein last effect is double the size of intermediate effects would provide 6% more evaporation than the conventional arrangement of all tail vessel having equal area. HTC values are presented for evaporator sets where this has been achieved by parallelizing existing vessels on vapour. It is concluded that for series juice feed, the advantage of lower brix in the fiest vessel of juice feed. The advantage of lower brix in the first vessel of the pair is offset by the absence of flash in the second vessel.