If you've never tried gel stains, you're missing out on what could be an important part of your finishing repertoire. In certain situations (that we'll tell you about) these thickened stains perform better than thin-bodied (liquid) stains. But, they do have limitations. And, as we discovered, subtle differences exist between the three major brands we tested.
To understand how these two types of stains behave differently, imagine a piece of wood as if it were a slice of bread. Applying a gel stain to wood is like spreading peanut butter onto bread. The peanut butter sticks, but it doesn't penetrate the porous surface of the bread. You can spread the peanut butter, but you can't apply it in a thin or translucent layer the way you can, say, warmed butter. Like fluid butter, thin-bodied stains go on thin and penetrate the surface.
Because gel stains lie on a wood surface instead of soaking into it, they uniformly color porous and nonporous areas alike. That makes them relatively goof-proof, and a great help to novice finishers. And, because they don't run or splatter, they're especially handy for applying to vertical surfaces.
Nevertheless, gel stains do have certain drawbacks. We avoid them on projects with lots of tight corners and crevices because the stain collects in these tight spots and is hard to remove. Thin-bodied stains don't have this problem because they wick into tight spots and the areas adjoining them. And, because gel stains don't penetrate as well as thin-bodied stains, they don't bring out the "depth" of the wood grain as well as thin-bodied stains. That's why we prefer thin-bodied stains for porous woods such as oak, ash, mahogany, and walnut.