An accordion bunch is made by folding the edges of each filler leaf inward, one leaf at a time, and stacking the folded leaves so air can pass through them. The bunch is then wrapped in a binder leaf. It is faster than entubado and, when done by a skilled roller, produces an equally even cigar. It is not the same as a book bunch, where the leaves are laid flat and folded over once.
The folds have to run the full length of the cigar. If the leaves are bunched into a lump in the middle, the result is a blockage (a “plug”), not an accordion bunch. The test of quality is whether the draw and the burn stay even after the bunch has been pressed in the mold.
Neither bunching method affects the flavor directly. They are simply ways of turning the blender’s recipe into a cigar.