It will spoil/go rancid. Even the 'non-natural' big brands like Jif/Skippy taste and smell 'off' if they sit out for a few weeks after being opened.
There's no winning here, because putting it in the fridge makes it hard to spread. The best approach is to take out a week's worth or so and put it in a small/airtight container. Leave that out but put the main jar in the fridge.
There's no winning here, because putting it in the fridge makes it hard to spread. The best approach is to take out a week's worth or so and put it in a small/airtight container. Leave that out but put the main jar in the fridge.