Boiler heater selection help

[Ayata]

Hi everybody,
I have the equipment consisting of a 50L belt heater (2,8kW) boiler, 1,5m/50mm copper column with reflux, a condenser and a fully automated distillation management system named roboimbik.
I now have a plan to upgrade the system with a 100L boiler and a 75-100mm column.
I usually ferment fruits, mostly grapes, distill for raki (a Turkish traditional brandy distilled with anise seeds and sometimes different fruits for brandy. So I do the distillation with the fruit, I have been using belt heater but as you know, belt heater is not an efficient one. Now I plan to use some type of internal heater but I am not sure which I should use, I don't want to burn the fruit or the anise seeds in the wash.
Would you recommend an internal heater that doesn't have the risc of burning solid things in the wash?

Regards and thanks in advance