Texture, appearance and flavor: These are the elements of meat that the new vegan alternatives from Impossible Foods and Beyond Meat are trying to capture, with varying degrees of success. Here’s how they do it:

Texture

In ground beef, animal protein provides springy texture and allows the meat to bind to itself. (Hamburgers would simply crumble if it didn’t.)

But mimicking the texture of animal protein using plant-based ingredients has always been difficult because of a fundamental difference between animals and plants: muscles, which are by necessity elastic and springy. To move their bodies, animals must be able to easily change the shape and tension of their flesh without damaging it. Plant cells, on the other hand, are relatively rigid and unflexing.

To put it simply, plants are crunchy, and meat is chewy. This is why veggie burgers can often feel crumbly or mushy in texture, without the bite and springiness of animal protein. To solve this problem, researchers have spent years isolating and cataloging a wide variety of plant-based protein sources. As a result, the texture of modern vegan meat — provided by wheat or pea proteins, among others — can be fantastic.

[Read the results of our taste test of plant-based meats.]

The other major factor in beef’s texture is animal fat, which provides mouth-coating richness and juiciness. Beef fat also tends to melt slowly, over a wide temperature range. This slow release of fat results in juiciness that lingers as you chew.