When sourcing a tomato paste evaporator, you must prioritize forced circulation technology to handle high-viscosity fluids and prevent 'burning' on the heat exchanger tubes. Key specs include the evaporation capacity (measured in kg/h), the number of effects (e.g., triple-effect or quadruple-effect to optimize steam economy), and the final Brix concentration (typically 28-30% or 36-38%). Ensure the equipment uses SUS304 or SUS316L stainless steel for all food-contact surfaces to prevent corrosion from the natural acidity of tomatoes.