Each species of hardwood possesses unique grain and cell structures, which affect the results of the coloring or staining process. Tight grain wood, such as hard and soft maple, and cherry, will often become blotchy when stain is applied. Open grained wood, such as oak or ash, often stain unevenly between the different textures of the wood grain, especially when trying to achieve deep colors.
To eliminate blotchiness on maples and cherry, a light wash coat may be applied prior to staining. A wash coat can be formulated by using one part of non-catalyzed vinyl sealer with 5-10 parts acetone. Increasing the ratio of vinyl sealer to acetone will provide more stain uniformity. Increasing the ratio of acetone to sealer will provide deeper stain penetration into the wood. (Using wash coats may impede achieving deep stain colors.)
On maple woods, a "grain popper" can be used by blending one part water with one part methanol, and lightly and uniformly spraying it over the wood. This process is a reverse of wash coating and will uniformly open up the pores of the wood to provide deep stain penetration. However, with some stain colors this may cause an undesirable, muddy effect.