In an edge grain cutting board, strips with vertical growth rings (vertical grain) move about half as much across the board's width as strips with flat growth rings (flat grain). For hard maple, that is roughly 0.14 inches versus 0.30 inches of seasonal movement on a 12-inch-wide board. It is the single most useful construction detail you can check by looking at the end of a board.
What do vertical grain and flat grain mean?
Look at the end of any strip of wood and you will see the growth rings. Their direction relative to the cutting surface is what matters:
- Vertical grain (also called quartersawn orientation): the rings run up and down, roughly perpendicular to the cutting surface.
- Flat grain (flatsawn orientation): the rings run side to side, roughly parallel to the cutting surface.
- Rift grain: anything in between, usually at 30 to 60 degrees.
Most lumber is flatsawn. When a maker rips it into strips and turns each strip on its edge, the rings rotate 90 degrees and usually end up vertical. That is one quiet advantage of edge grain construction over a single plank laid flat. Our post on how edge grain cutting boards are made shows where this happens in the process.
Why does ring direction change how much a board moves?
Wood shrinks and swells unevenly. According to the USDA Forest Products Laboratory, it moves most along the growth rings (tangentially), about half as much across them (radially), and only slightly along the grain (Wood Handbook, ch. 4).
For hard maple, green-to-oven-dry shrinkage is 4.8% radial and 9.9% tangential (The Wood Database). A vertical grain strip moves across its width in the radial direction. A flat grain strip moves in the tangential direction. That is the whole difference.
How much does an edge grain maple board actually move?
The Wood Handbook gives a formula for estimating movement between 6% and 14% moisture content: change in width = starting width x dimensional change coefficient x change in moisture content (Wood Handbook, ch. 13, Table 13-5). For sugar (hard) maple, the coefficients are 0.00165 radial and 0.00353 tangential.
At 70°F, wood settles at about 6.2% moisture in 30% humidity and 13.3% in 70% humidity (Wood Handbook, ch. 4). Here is what that 7.1-point swing does to a 12-inch-wide hard maple board:
| Strip orientation | Coefficient | Calculation | Width change |
|---|---|---|---|
| Vertical grain (radial) | 0.00165 | 12 x 0.00165 x 7.1 | about 0.14 in (roughly 9/64 in) |
| Flat grain (tangential) | 0.00353 | 12 x 0.00353 x 7.1 | about 0.30 in (roughly 5/16 in) |
That is a worst-case seasonal swing, from a dry winter to a humid summer. Most kitchens move less. The ratio holds either way: flat grain moves a little over twice as much.
Does more movement mean the board will cup or crack?
Not by itself. Problems come from uneven moisture, such as one face getting wet while the other stays dry, or a board drying out fast next to a heater. Flat grain strips are more prone to cupping because the rings try to straighten as they dry. Vertical grain gives the board a wider margin, but no construction makes a wood board immune to cupping or cracking if it is soaked or left wet on one side. Our guides on why cutting boards warp and cracking in winter cover the habits that matter most.
How can you check the grain on a board before you buy?
- Look at both ends. On each strip, see which way the ring lines run. Mostly up-and-down lines means vertical grain.
- Ask for a photo of the end if you are buying online. A maker who orients strips carefully will be glad to show it.
- Check for alternating curves. On rift or flat strips, good makers flip every other strip so the ring curves alternate.
- Press the corners on a flat counter. A board that already rocks in the box has moved since it was flattened.
Does grain orientation matter on an end grain board?
Less for the cutting surface, because you are looking at fiber ends rather than rings. It still matters for how the board moves across its width and length, just as it does on edge grain. Compare the two constructions in our end grain vs edge grain guide.
Frequently asked questions
Is vertical grain the same as quartersawn?
In a cutting board, yes for practical purposes. Both mean the growth rings run roughly perpendicular to the wide surface you see.
Is a vertical grain edge grain board better for knives?
Not noticeably. Knife feel on edge grain depends mostly on species and hardness. Grain orientation mainly affects stability.
Why is my edge grain board slightly wider in summer?
Higher humidity raises the wood's moisture content, so the board swells slightly across its width. It gives the moisture back in drier months. That is normal.
Does oil stop an edge grain board from moving?
No. Oil and wax slow down how fast moisture moves in and out, which helps prevent sudden, uneven changes. They do not stop wood from responding to humidity over time.
Last reviewed September 2026 by James at Bevel & Bond. Figures from the USDA Forest Products Laboratory Wood Handbook (FPL-GTR-282) and The Wood Database.
Keep moisture changes slow and even. A coat of Board Balm after washing, and drying the board on edge, does most of the work. Shopping for a board now? Start with our end grain maple cutting board.
