Cooperage is the art of making and repairing wooden barrels and casks. The people involved in this work are called coopers. Wooden barrels and casks are not nearly as popular now as they were in the 1800s and early 1900s.

Barrels made of tight cooperage could hold liquids, and barrels made from loose cooperage were generally used for solids like grains or nails. To have tight cooperage, the barrel staves had to be made from species of wood that had cells that would resist letting liquids seep through.

White Oak is the most common species group used for tight cooperage. White Oak, like the Red Oak group, has large cells that can be easily seen with the naked eye (no lenses needed). Yet, the Red Oaks would let liquids run through the cells.

We can see the open pores in Red Oaks on a clean-cut cross section. When we look at a clean-cut White Oak cross section, we can actually see that the pores seem to be filled by a whitish spongy-looking material. . This material is called tyloses and, in fact, it restricts the movement of liquids through the cells. You may have heard of White Oak barrels being used for wine or whiskey storage.

A fun experiment can be made with a 1" x 1" x 6" piece of White Oak and one of Red Oak. Fill a clear glass with water and place the end of the White Oak stick into the water and blow from the other end. Nothing happens. When you do the same with the Red Oak stick, lots of bubbles form at its bottom end, because the open pores allow the air to go through the length of the stick.

Try it for some rainy Saturday fun.