How to raise fermentation temp?

Hello I am going to brew some belgian beer’s. An I read that you should start fermentation in the low 60’s an let it raise up into the 80’s. Now my ? is how do you start to raise the temp I have a ranco dual temp controller that can do both cooling an heating … Like let say i want to brew a saisson I know by listing to jamil he say to starter at 68F an over a week time to raise the temp to 80F . Now here where I am try to ramp my head around is are you let it naturally let the heat of fermentation raise it for you or are you use the temp controler to do the raise… An how do one use the dual temp controller for this do I run the heating an cooling at the same time or do i just use the heating if i use the heating do i still use the cooling so the temp does not get out hand

I just allow the heat from fermentation raise the heat. Just adjust your temp control per day (say 2*-3* per day). For example if you are starting at 65* set it for 68* when you want to ramp up, then 71* so on and so forth.

If the fermentation isn’t raising the temps enough you could get a brew belt or even set the fermenter on a heating pad.

I have the dual controller on a conical heated/cooled fermenter. Make sure that you set the cool higher than the heat part and make sure you have a high enough differential. However, I don’t think you need it as I never have used both at the same time…