1. stage 1 : the oak
(AKA QUERCUS)
WHAT'S IN A NAME?
If your last name is “Cooper” or “Hooper” chances are that your ancestors were
employed in the ancient craft of barrel making and repairing, known as coopering.
The word “cooper”, also referred to as a “hooper”, comes from the old English word,
“Couper” and Dutch word, “Cuper”. The word originates from the barrel makers
of Illyria and Cisalpine in Roman Gaul (modern France), where wine was stored
in vessels called “Cupal” and the maker was a “Cuparius”. Can you think of any
other English words derived from this Latin word that we use today?
SOURCE
STRUCTURE
Species used for tight cooperage of wines and spirits (almost exclusively).
Q. PETRAEA
Q. ROBUR
RADIAL RAYS
WHY DO WE STILL
USE OAK BARRELS?
In a world that favors stainless steel and non-reactive materials for storage, there
is really only one reason why there is a flourishing coopering industry today:
Certain beverages, such as wine, spirits and beer, benefit from being stored in
wood—namely oak.
ADVANTAGES OF OAK
HOW FAR BACK DOES IT GO?
Straight-sided, open wooden buckets date back as far as 2690, BC in Ancient Egypt.
Closed barrels were first developed around 800-900 BC, and by the first century
BC, were used regularly for storing wine, beer, milk, olive oil and water. Organized
Coopers’ guilds originated in Rome, grew and flourished during medieval Europe
and reached their zenith in the late 19th Century. Barrel use dwindled rapidly after
World War I as other materials replace their use, such as metals and synthetics.
FRENCH OAK VS. AMERICAN OAK
MINIMAL
SHRINKAGE
BENDABLE
TYLOSE
Radial rays are elongated cells that extend radially
from the pith (center) to the bark, along the trunk axis.
They are vital to the transport of water and nutrients
through the tree. A higher concentration of radial rays
makes the wood of the tree strong and resilient.
Q. ALBA
Oak is a ring porous wood. The pores permit the flow of
water and nutrients. These pores become plugged with
cellular inner growth called tylose, and the sapwood
becomes hardwood. The tylose plugged pores render
the oak wood impervious to the movement of liquid.
In American White Oak (Quercus Alba), radial rays
make up 28% of the volume of the wood, compared
to 15% in other hard woods, and 8% in conifers. The
greater number of radial rays resists the diffusion of
liquid through the side of the barrel.
Oak staves are cut so that the radial rays run parallel to
the width.
CELLULOSE
Cellulose has no direct effect on flavor. It does play
a role in the flavoring of beer if Brettanomyces is
added. Cellulose is a nutrient for ‘Bret’, when a
barrel plays host.
HEMICELLULOSE
A 5-chain wood sugar. Heat treatment of the wood
causes decomposition of hemicellulose, yielding
carmelized flavors and aromas.
OAK TANNINS
Add astringency, contribute to mouthfeel and help
promote oxidation byproducts. A major role in seasoning
and toasting oak is to break down the tannins into a
more acceptable and less astringent form.
2 OTHER IMPORTANT OAK COMPONENTS:
LIQUID TIGHT
OAK LACTONES
Contribute the unique woody flavor and aroma found in
bourbons and whiskies. There is a higher concentration in
American oak than European oak.
Approximately 10% tannin by weight
(YIELD STRAIGHT-GRAINED STAVES)
NO OBJECTIONABLE
FLAVORS
STRONG WOOD
Maximum of 2% tannin by weight
Cis to Trans ratio of 2:1
LARGE TREE
Tanins
(Mouthfeel, Antioxidants)
Oak Lactones
(Cis = more coconut,
Trans = more celery)
Cis to Trans ratio of 10:1
Less dense compared to American Oak,
has different toasting regimes to achieve
targeted flavors
Intensity of Aromatics
More intensity, more woody notes when
toasted for a short time or at a low
temperature
Increase in the temperature or duration
increases smoke notes
Their contribution to flavor and aroma is predominantly
woody, coconut and celery-like aromas, but can also lend
apricot, lavender and orchid aromas (Y-nonalactone).
TERPENES
Compounds found in oak that contribute tobacco, leather,
and tea aromas and flavors.
LIGNIN
A three dimensional polymer, that is one of the most
abundant naturally occurring materials on earth. Oak
lignins are degraded by heat, hydrolysis, oxidation and
microbial action, playing an important role in flavor,
most notably, sweet vanilla.
Upon further breakdown and oxidation, lignins
contribute cinnamon, nutmeg, clove, and smokey
medicinal aromas.