@manu Generally you need to be within a range for best results depending on what you're fetmenting. Most beer and sauerkraut like to be between around 65-72F while fermenting to get proper flavors (though you can still get a good product if you're off a bit). Too low a temp and the ferment can be incomplete, too high and it can ferment too fast giving off-flavors. Think of it like cooking a piece of meat: too low and it won't cook through, too high and you burn it.
"I appreciate SDF but it's a general-purpose server and the name doesn't make it obvious that it's about art." - Eugen Rochko