Trades – The Cooper

Today, we’re used to our food showing up in the grocery store nicely packaged for us to pick up and take home, but things weren’t always this way. Before packaging became such an important part of the overall advertising of products, many were shipped to retailers in bulk to be weighed and packaged in paper bags or brown paper wrappings.

Shipping in bulk meant barrels and casks were required for a lot of products – the work of the cooper. While not every village would have their own resident cooper, master coopers could be found in all the major cities as well as towns and villages that produced products that needed their packaging.

The true masters could read the grain of a piece of wood better than you and I could read a road map

Today, there are less than 50 master coopers left in the United States; at one time, there were thousands. An apprenticed skill, the master cooper worked for four years to learn every part of the trade before being considered a journeyman. The true masters could read the grain of a piece of wood better than you and I could read a road map.

Making barrels requires this level of skill because they are joined together without any sort of glue or other adhesive. While the flavoring that the wood imparts to the contents is something to be desired, any flavoring from chemicals could ruin the products stored within. Each part of each barrel has to be made perfectly so that the finished barrel can seal properly and be both watertight and airtight.

Today, wood barrels are mainly only used for storing wine and whiskey

Today, wood barrels are mainly only used for storing wine and whiskey. These barrels are usually made of oak because of the flavor oak imparts into the beverages being aged and fermented in the barrels. Other products that might require barrels, such as chemicals, are mostly shipped in plastic barrels or plastic-lined cardboard barrels – industrial containers that don’t require a lot of skill to manufacture.

Making a Barrel

The barrel-making process begins with the selection of the wood. Oak is popular because its dense, fine grain seals well. Master coopers often select the wood by buying logs at auction, which are then shipped to the coopery. There, they are cut into boards and stacked for two to three years of seasoning in the open air.

Staves are the most important part of the barrel, and these are cut and planed from the seasoned boards. A barrel will have between 30 to 32 staves in it, depending on the size of the barrel and the size of the staves. Individual staves vary in width but are generally categorized as wide, narrow, and medium.

Staves are the most important part of the barrel, and these are cut and planed from the seasoned boards

The staves are planed on both the outside and inside, which gives them a slight cup to match the final curvature of the barrel. They are also planed to make the ends narrower than the “bilge” – the wide middle part of the barrel.

Selecting the staves for an individual barrel is a bit of a puzzle because they vary in width. However, a master cooper is not just concerned about the width of the staves; they’re also concerned about the grain and any knotholes.

Some staves can’t be used for barrels that are intended to hold wine or other liquids but can only be used for holding dry goods like flour, which won’t leak out through the grain.

A cooper readies or rounds off the end of a barrel using a cooper’s hand adze – Author: Soerfm – CC BY-SA 2.0

This difference in stave width means that each barrel is an individually-crafted item and not really a mass-produced product. The heads of the barrel must be made to match that barrel as the overall size will vary slightly.

Setting the staves together is called “raising the barrels.” A temporary hoop, which is thicker than the permanent hoop, is used for one end and the staves are stacked in place by hand, alternating their width in a pattern of wide, narrow, medium, wide, narrow, medium, to spread the stresses evenly around the barrel. The final stave may have to be hand-planed to fit.

With the staves in place, the wood is heated so it can be bent. Heating wood is common for bending it in a variety of different applications, such as in making the sides of an acoustic guitar.

A clamp or cable is wrapped around the loose ends of the hot staves and tightened, drawing the edges of the staves together to create the final shape. A second, temporary hoop is placed on that end of the barrel to hold it together.

A cooper – Author: Kerkvorst – CC BY-SA 3.0

Although the barrel now has its final shape, it is far from done. Barrels used for wine and whiskey are toasted next – charring the inside surface and crystallizing the sap. This is done by placing them over an open fire. Barrels that would have been used for butter or salt fish would not have been toasted as there was no desire for the wood to affect the flavor of its contents.

In some cases, the outside of the barrel is then sanded – more for appearance than for any other reason. This step was mostly ignored in ancient times because barrels were built for utility rather than appearance. If we go far enough back in history, sandpaper wasn’t even used so a scraper would have been used to smooth the outside by working in the direction of the grain.

At this point, the actual hoops were placed on, replacing the temporary hoops that had been used for forming it. These would have been made by the blacksmith, although in modern cooperies they rivet galvanized steel straps together to make the hoops.

A wooden barrel

The hoops are driven onto the barrel, starting with the hoops that go closest to the center and working outwards. Most barrels had six hoops, although smaller ones might have only four and extra-large barrels might have eight.

The cooper would use a wood driver, a special punch, to drive the hoops into place. There were no fasteners used for holding these hoops on the barrel; instead, the spring tension between the wood and metal held them in place.

This meant that an old barrel that had been left out in the sun could have the hoops come loose and begin to leak. However, all it would take to make that barrel useful again would be to drive the hoops down onto the barrel and soak it in water.

With the hoops in place, the heads still needed to be installed. These would be made to fit and would set into a “croze” – a groove about 1½ inches from the ends of the staves cut into the inside of the barrel with a tool by the same name, which was a special plane for cutting this groove.

The last step is to drill the bung hole and insert the bung plug – at least for barrels that are used for liquid goods. For those used for dry goods (flour, sugar, etc.) there is no bung needed. Instead, one of the heads is made to be removable, although removing the lid is not usually easy.

Barrels for Survival

One of the truly great things about barrels is that they are readily reusable. Good quality barrels can be buried underground for storing food, and they were used that way in the colonial era of our country. A barrel buried so that the lid is at ground level can be used as a makeshift root cellar.

I wouldn’t recommend planning on making your own barrels in a post-disaster world unless you learn how to now. While they may seem simple enough, the exactitude that needs to be applied in cutting the staves is difficult enough that I seriously doubt anyone would get it right on their first or even tenth try.

If you are going to need barrels for liquids, it is better to buy them commercially than to hope to make them yourself.