It is important that a binder is used to help bind everything together to prevent patties from falling apart easily. In this spicy black black bean burgers, oats is used as a binder to make sure everything stays together. Other than that, the texture of burger mixture also plays a huge role. If your mixture is too chunky, they are less likely to hold together well. Aim for a smoother batter with most of its ingredients finely chopped. When forming patties, your mixture should be able to hold its shape well. For an even firmer patties, you can take the extra step to refrigerate your mixture for 15-20 seconds before shaping.