Red eye gravy and tomato gravy are not the same thing.
Although regional variations of red eye gravy and tomato gravy can cause confusion between red eye gravy and tomato gravy.
Tomato gravy is a thicker and often roux based gravy that is made with bacon grease, tomatoes and other seasonings.
And red eye gravy is a thin, savory sauce that is made from pan drippings of country ham and black coffee.
The key ingredients in red eye gravy are country ham drippings and strong black coffee.
The flavor profile of red eye gravy is salty, smoky and slightly bitter from the coffee and red eye gravy also is a thin, thin sauce with a reddish circle of fat on top and red eye gravy is also often served with country ham, grits, biscuits or cornbread.
The key ingredients in tomato gravy are bacon grease or other fat, flour, "for a roux", and tomatoes.
The flavor profile of tomato gravy is tangy and slightly richer than red eye gravy, with a distinct tomato flavor.
And tomato gravy is also a thicker and more opaque gravy which can vary in color.
Tomato gravy is also a heart gravy that is often served with biscuits, cornbread etc.