I am purchasing 5 Gallons of fresh pressed unpasteurized cider from a local orchard. It is treated with UV rays. Do i need to heat this to kill off any unwanted yeast strains or will the UV take care of that for me. Thanks
The UV will kill any wild organisms, so you dont need to heat or add campden/k-meta (I wouldnt do either for unpasteurized juice either)
After the fermentation is done, if you are planning to keep any beyond 6 months or so, you can add a half a dose of campden as a preservative - but dont add it to anything that you are planning to drink in the next 6 months because it will leave a bitter aftertaste that takes several months to fade