Cooperage is the ancient craft of barrel making; an artform, really, that results in a water-tight, wooden vessel held together by nothing more than the hoops that surround it.
Cooperage Over Time
Wooden barrels have been used store and transport all manner of goods for more than 2000 years. There is evidence that the Romans first used barrels as early as the 3rd century AD, replacing the clay pots and other breakable vessels they had been using previously. That’s 2000 years of history, of the evolution of a craft, and of perfecting an artform.
As the crafting of the barrels must be absolutely precise, the value of the men creating them increased and the art, and trade, of cooperage was born. Coopers are so called after the German, and Latin, terms for the barrels they create; kūpe or cupa which, when expanded, became the term cooper. Interestingly, much like the trade of blacksmithing produced the surname Smith, the trader of coopering produced the surname of Cooper. A namesake based on an ancient trade and artform.
Cooperage has, in fact, not changed very much at all over its 2000 year history. A barrel made today is made in very much the same manner it was back then; the selection and aging of the wood, the preparation of the staves, and the end construction are all still very similar. There are nods to technology such as the use of band saws and sanders but, at its heart, the process remains unchanged.
Check out this video showing beer barrels being crafted in the 1950’s at St. James Gate in Dublin, Ireland.
And this modern video from Nadalie Cooperage in California. You can see that the processes in both videos are very similar even if some of the tools have evolved.
Anatomy of a Wooden Barrel
It is the simplicity of a wooden barrel that makes it so special. No glue, nails, or screws are used; simply the wood and hoops to hold it together. Coopers have terms for every part of a barrel and specific ways that they should all go together to make the perfect wooden barrel.
Staves are the heart of the barrel. Created from oak that must be straight, knot-free, and properly aged, they are shaped and fitted together in a precise pattern that will render the finished barrel water-tight.
Hoops are almost always metal; steel, copper, or unusually, iron. Typically a barrel will have:
- 2 Chime (or Head) hoops at the outer edges of the barrel
- 2 Quarter hoops about ¼ of the way to the center of the barrel
- 2 French hoops between the Quarter hoop and the Bilge hoop
- 1 Bilge hoop encircling the widest part of the barrel
The chime is the bevelled edge at the top, and bottom, of the barrel. It is made up of the ends of all the staves coming together.
The croze is the groove that is created at the top and bottom of the barrel staves. It is created to hole the head.
The flat, circular top, or bottom, of the barrel. As each barrel is completely unique, each head must be measured and created specifically for the barrel it will fit.
How to Make a Wooden Barrel
Although a wooden barrel is, at its simplest, a collection of wooden staves held together by hoops, it is the culmination of talent and craft that produces the resulting work of art.
Selection and Preparation of the Oak
It is the selection and preparation of the wood that goes into making a barrel that determines the quality of the barrel in the end. Coopers like to know the pedigree, or history, of the wood they are using. They’re interested in the age of the trees, the location they are grown in, and the growing conditions of the area. They are the final decision makers as to what wood is used to craft their wine barrels, whiskey barrels, and bourbon barrels.
The first decision is which oak to use; French, American, or Hungarian. French and American oak dominate the world barrel market with American oak being used much more often than French these days. This is due to changing taste palettes (American oak imparts a stronger vanilla flavor than French oak, which is more popular today) and cost considerations as American oak is a much less expensive wood than French oak.
Regardless of the origin of the oak, the wood selected must be straight and knot-free. The grain should be tight and predictable and the tannin content should be high in order to impart as much flavor into the aging liquid it is intended to hold.
The best barrels are made from oak that is hand split to preserve the grain and keep the veins intact, but often saws are used today to reduce both time and cost. Once the wood is roughed into stave length it is stored in tiers, exposed to weather and elements, to age and mature. This makes the wood stronger and removes any unwanted odors and tannins that may impart a harsh flavor. The wood is aged for several years.
Creating the Barrel Staves
Once the oak has been roughed out and aged the final production of the staves takes place. The wood is cut to stave length, tapered on every edge (both sides, top and bottom) to an exacting standard, hollowed slightly on the inside plane, and sanded to a smooth finish.
Staves are created in varying widths to accommodate the construction process of alternating stave widths to increase strength.
Staves may be create by a junior cooper but are always inspected for quality and standards by a master cooper. It is he who is ultimately responsible for the quality in the finished barrel.
Construction of the Barrel
The final construction of the barrel is an integrated process that includes piecing together the staves, using the hoops to pull them together, toasting the inside of the barrel, inserting the head(s), and drilling the bung hole.
First off the chime hoop is used as a template while the staves are added one by one around the entire diameter. Some coopers use staves of one equal width but many coopers now use a pattern of narrow, mid-width, and wide staves around the barrel. This increases the strength of the barrel and allows the forces to be disipated more easily.
Once the barrel staves are all inserted in the primary chime hoop, a quarter hoop is placed to more firmly secure the staves. This part of the process is called ‘mise en rose’ which translates to ‘setting the rose’; at this point the barrel resembles an opening rose as the still straight staves bloom outward from the primary chime, hence the term.
Next, the staves must be shaped and set into the barrel shape. The partially built barrel is typically set over a steamer to soften the wood allowing it to bend. These days a cable system is often used to bring the lower portion of the staves together so that the final hoops can be applied. The shape will be set once the barrel cools and dries resulting in a water-tight barrel without the use of any glue, nails, or screws.
The barrel is now toasted over an open flame – although sometimes this process is completed at the same time as the stave shaping above. Coopers use gas flame, oak fires, or torches to char the inside of the barrel to whatever level of toasting the client has requested.
The final step is to create, and set, the head of the barrel. Each barrel may have the same rough measurements, but the exact diameter and shape of each is quite varied. For this reason, each head is crafted individually based on the exact measurements of the barrel it is intended for.
Cooperage is as much of an art today as it ever has been. The talent and skill of those who craft wooden barrels is unmatched today as a manual artform. It is the essence of form and function created by craftsmen who take pride in their work.