It depends on the type of vinaigrette you’re making use of. Basic vinaigrette can be stored for weeks without getting sour but ensure that you watch it. In contrast, fresh vinaigrette with fresh, new ingredients can only last for a couple of days, sometimes 2-3 days but ensure that it is well ventilated or kept in a fridge so as not to lose its taste. When you remove your vinaigrette from the fridge, you have to warm it, and to do that, just set your container in hot water for a moment. That will make it warm again.