Grain in Briar

Grain (English grain) is the collective name for the lines, rings, and speckled patterns on the surface of a briar pipe. It's not decoration; it's the tree's anatomy: the capillary channels that carry water inside the underground burl of the tree heath reflect on the surface in different forms depending on the angle at which they're cut. Grain in a pipe therefore reveals both where in the burl the wood came from and how the maker oriented the block.

From Capillary Channel to Pattern

Tree heath (Erica arborea) develops a woody burl called a lignotuber between its trunk and roots. This is the water and nutrient reservoir that lets it resprout after fire or drought has taken the upper part of the plant; field studies indicate that replenishing the reservoir once spent takes years. As the burl grows slowly, thin channels form to carry water upward, fanning outward from the center. What a block promises can only be seen once the burl is split; this uncertainty is one of the most nerve-wracking stages of pipe making.

Reading the Patterns

Pattern	Appearance
Straight grain	Closely spaced parallel lines running vertically along the bowl
Flame grain	Lines that widen and flare out like a flame as they rise
Cross grain	Lines running horizontally instead of vertically
Birdseye	The end-cut cross-section of the capillary channels; a texture of dots and small rings
Mixed grain	A surface with no single direction, where patterns intertwine

Viewed from the side, these same channels appear as lines; viewed head-on from their very end, they appear as small rings. Straight grain and birdseye are, for this reason, two faces of a single structure. In a bowl with well-oriented grain, the lines fall on the side surfaces while the birdseye texture falls around the rim and base. Because the channels fan outward from the center, a flawless parallel grain running unbroken around all four sides of a bowl is very rare; straight-grained bodies are for this reason gathered into most manufacturers' top grades. It should also be added that there is no common grading system; the tiers and criteria vary from brand to brand.

Where Grain Ends

Not every part of the burl is grained. The reddish zone at the center stores water and doesn't contain capillary channels, so it has no pattern. In the bands where branches begin inside the burl, the lines suddenly scatter, giving way to a swirling, directionless texture; this is what English sources call "branch wood." Add to this a further flaw: as the burl grows, it responds to stones, gravel, and wood-boring insects by sealing the resulting gap with new wood, leaving a mark distinct from its surroundings. These marks, called sand pits, are usually only a few millimeters across, but a block coming out entirely clean from end to end is not to be expected.

The Weight of Grain

If a flaw surfaces and can't be removed by sanding, the body is either covered with filler putty or steered toward a textured finish; the choice among surface finishes is largely decided right here. Sandblasting doesn't give the expected result on a grainless body, since it abrades the soft texture and leaves the hard grain standing in relief; such blocks are mostly steered toward a rustic finish.

Whether grain affects smoking quality has long been debated in pipe circles; neither side of the argument rests on a conclusive measurement. What isn't disputed is the visual and tactile value of grain, and its weight in the grading tiers of both artisan and factory production.