Maison Media

Oak Barrels: French vs American Oak, Split vs Sawn, and What Toasting Does

Why French oak staves are split and American oak staves sawn, how much oxygen a new barrel lets into wine, and what toasting does to the wood.

An oak wine barrel is a wooden vessel, commonly made of French oak (Quercus robur or Q. petraea) or American white oak (Q. alba), that releases wood compounds into wine and lets small amounts of oxygen reach it during maturation.

Part of: Winemaking

Maison Media Editorial · Published Sep 21, 2026 · Updated Oct 11, 2026

A man in glasses and a dark apron draws red wine from a barrel with a glass pipette and holds a wine glass, between rows of barrels in a vaulted stone cellar — Barrel tasting in a vaulted cellar: a sample of red wine is drawn from the top of a barrel with a glass pipette.
Image: Maison Apéro (generated image) · Maison Apéro original

What a barrel adds to wine

A barrel is not a neutral container. It is an active vessel: the wine extracts compounds from the wood, and small amounts of oxygen reach the wine by several routes.

Several things govern this gas exchange: the pressure drop that develops inside the barrel, the formation of a headspace, the anatomy of the wood, the different routes by which oxygen enters, the moisture of the wood and its soluble ellagitannins, and the toasting of the barrel. The rest of this article follows those levers from the tree to the cellar.

Cross-section illustration of a wine barrel on wooden chocks in a cellar: oak staves with iron hoops, a dark toasted inner face, red wine-soaked wood below the wine line, a bung with a small headspace beneath it, and a magnified window showing pores in the wood — A barrel lying on its side in the cellar, drawn in cross-section with wine inside; the window at lower right magnifies the end grain of a stave. Each label names a factor in how the barrel acts on wine. Shapes, colours and thicknesses are illustrative, not measured.
Read the figure as text
**Staves** — Rays, tyloses and stave placement limit the passage of wine and air
**Wine-soaked wood** — Soaking lowers the oxygen entering through the wood
**Bung and headspace** — Headspace formation is one factor in gas exchange
**Toasted inner face** — Heat breaks down part of the lignin, cellulose and hemicellulose
**Wood pores** — Oxygen released from the pores also reaches the wine

Which oaks: French and American

Barrels sold as French oak are made from two European species, pedunculate oak (Quercus robur) and sessile oak (Q. petraea). In the studies cited here, American oak means white oak (Q. alba). A 2017 study in the Journal of Agricultural and Food Chemistry compared 8 cooperage woods of Q. alba and Q. petraea, two species commonly used by coopers.

Not every oak can hold wine. A 2024 X-ray tomography study in Scientific Reports compared Q. alba, Q. robur and northern red oak (Q. rubra). The pores of the white oaks were filled with about 7 times more tylose volume than those of red oak, consistent with earlier reports that white oak casks hold liquid and red oak casks do not. Tyloses are balloon-like structures made of cell wall that grow into the wood's vessels and plug them.

Why French oak is split and American oak is sawn

The cutting method follows the tyloses. Because French oak has fewer tyloses, its staves must be obtained by splitting the trunk, whereas the higher tylose content of American oak allows them to be sawn.

Splitting follows the medullary rays, so the rays in a French oak stave keep a constrained orientation; sawn American oak staves show more variable ray orientation. That matters because rays, tyloses and the way the stave is placed in the barrel together keep wine and air from moving freely through the wood.

The choice also costs wood. Only about 20–25% of a split French oak log is usable, and sawn American oak is at least twice as economical.

Illustration of two oak log ends: on the left a French oak log split into wedges along its rays with two staves outlined, on the right an American oak log cut by parallel saw lines with one board outlined as a stave — Two log ends seen face on. Pale radial lines are the medullary rays, white lines the splits and saw cuts, and the outlined pieces are staves. In a laboratory comparison of cooperage woods, French oak also let in more oxygen than American oak in every case. Shapes and colours are illustrative; the drawing does not show how much of each log is used.
Read the figure as text
**French oak: split** — Q. robur, Q. petraea. Fewer tyloses, so the trunk is split along the medullary rays
**American oak: sawn** — Q. alba (white oak). More abundant tyloses allow the staves to be sawn
**Split stave** — Ray orientation constrained by splitting
**Sawn stave** — Ray orientation more variable
**About 20–25% usable** — Of a split French oak log
**At least twice as economical** — Sawn American oak, compared with split French oak

How much oxygen passes through a barrel

Oxygen figures for barrels depend on how they are measured, so it helps to know where a number comes from. In a 2021 OENO One study, Rémy Junqua, Liming Zeng and Alexandre Pons placed a whole new barrel of sessile oak (named Q. sessilis in the paper) inside an airtight stainless-steel tank and followed the oxygen in the atmosphere around it. They measured an oxygen transfer rate (OTR) of 11.4 mg/L a year through the barrel. Counting also the oxygen released from the wood's pores, the new barrel supplied 14.4 mg/L a year to the wine, and 46% of it arrived in the first three months.

Species matters too. In the 2017 laboratory comparison of 8 cooperage woods, French oak (Q. petraea) let in more oxygen than American oak (Q. alba) in every case. Impregnation of the wood lowered oxygen entry in both species, to different degrees.

These are results of specific experiments, not a constant for every barrel: used barrels, other species, other toast levels and cellar conditions lie outside what these studies measured.

Toasting: what heat does to the inner face

Toasting is the stage in which the cooper heats the inside of the assembled staves. The heat breaks down part of the wood's polymers — lignin, cellulose and hemicellulose — into volatile and non-volatile compounds. The wine extracts them during maturation; lactones are among them, and together they are associated with smoky, woody or vanilla aromas. Toasting is also one of the factors that change a barrel's gas exchange.

Coopers make barrels at different toast levels, and the effect is still being measured. Recent trials combine toast levels and grain sizes in Q. petraea barrels and follow the volatile profile of Tempranillo red wines, or study how toast level influences the aroma, phenolic composition and sensory properties of red wine.

A cooper in a leather apron and gloves tends burning wood with an iron hook inside an open barrel on a brick hearth, with staves, hoops and barrels in the workshop behind him — A fire burns inside an open, hooped barrel resting on a brick hearth; the cooper tends it with an iron hook as smoke rises in the workshop.

Image: Maison Apéro (generated image) · Maison Apéro original

In the cellar and in the glass

For the winemaker, the barrel is a set of choices: French or American oak, toast level, the share of new barrels, barrel size and time in wood. The Maison catalogue shows the range, from a Ribera del Duero crianza aged in a combination of French and American oak barriques to Chardonnays aged in French oak.

Tasting notes commonly link American oak with coconut and sweet vanilla, and French oak with subtler spice. Treat these as tendencies, not identification rules. Species, the way the stave is cut, toasting and the barrel's own oxygen supply all vary, so a tasting note alone is not evidence of where the oak grew.

Table comparing French and American oak barrels: species, tyloses, split or sawn staves, usable wood, oxygen entering the wine and toasting — Species, tyloses, how the staves are cut, how much of the log is used, oxygen and toasting, as the sources cited in this article state them. The oxygen figures come from one study of one new sessile-oak barrel, not from every barrel.
Read the figure as text
Figure as a table
French oak American oak
Species Quercus robur, Q. petraea Q. alba (white oak)
Tyloses Fewer More abundant
Staves Split along the medullary rays; ray orientation constrained Sawn; ray orientation more variable
Usable wood Only about 20–25% of a split log Sawn staves are at least twice as economical
Oxygen into the wine One new sessile-oak barrel: 11.4 mg/L a year through the wood, 14.4 including the pores In a lab comparison of 8 cooperage woods, it let in less oxygen than French oak every time
Toasting Heat breaks down lignin, cellulose and hemicellulose in part; lactones pass into the wine The same process

Figure as a table
	French oak	American oak
Species	Quercus robur, Q. petraea	Q. alba (white oak)
Tyloses	Fewer	More abundant
Staves	Split along the medullary rays; ray orientation constrained	Sawn; ray orientation more variable
Usable wood	Only about 20–25% of a split log	Sawn staves are at least twice as economical
Oxygen into the wine	One new sessile-oak barrel: 11.4 mg/L a year through the wood, 14.4 including the pores	In a lab comparison of 8 cooperage woods, it let in less oxygen than French oak every time
Toasting	Heat breaks down lignin, cellulose and hemicellulose in part; lactones pass into the wine	The same process

Practice question 1: split or sawn

Question
Explain why French oak staves are split and American oak staves are sawn, and what this means for the stave and for the use of the log.

Model answer
French oak (Q. robur, Q. petraea) has fewer tyloses blocking its vessels. To keep the staves watertight, the cooper splits the trunk along the medullary rays, which fixes the orientation of the rays in the stave. American white oak (Q. alba) has more abundant tyloses, so it can be sawn; sawn staves show more variable ray orientation. Rays, tyloses and the placement of the stave together limit the passage of wine and air through the wood. Splitting uses only about 20–25% of a French oak log, while sawing American oak is at least twice as economical.

Self-check points (Maison's own guide, not an official mark scheme)
- Gives the amount of tyloses as the reason for the cutting method
- Links splitting to the medullary rays and to watertightness
- Contrasts the use of the log (about 20–25% when split)

Practice question 2: oxygen and toast

Question
Using published measurements, describe how much oxygen a new barrel can supply to wine, how the oak species affects it, and what toasting changes in the wood.

Model answer
In one study of a new sessile oak barrel, the oxygen passing through the barrel came to 11.4 mg/L a year; with the oxygen released from the wood's pores the total was 14.4 mg/L a year, 46% of it in the first three months. In a comparison of 8 cooperage woods, French oak let in more oxygen than American oak in every case, and impregnation of the wood reduced oxygen entry. Toasting breaks down part of the lignin, cellulose and hemicellulose of the inner face into compounds, including lactones, that the wine extracts and that are associated with smoky, woody or vanilla aromas; toasting also affects gas exchange.

Self-check points (Maison's own guide, not an official mark scheme)
- Quotes the measured figures with their conditions (a new barrel, one study)
- States the species difference and the effect of impregnating the wood
- Names the polymers broken down by toasting and does not invent toasting temperatures

From tree to glass: how a barrel acts on wine

Step 1

Wood

French oak (Q. robur, Q. petraea): fewer tyloses, staves split along the rays
American white oak (Q. alba): more tyloses, staves sawn

Step 2

Barrel

Toasting breaks down part of the lignin, cellulose and hemicellulose of the inner face
Oxygen passes through the wood and is released from its pores

Step 3

Wine

Extracted compounds, including lactones, are linked with smoky, woody or vanilla aromas
A slow oxygen supply: 14.4 mg/L a year from a new barrel in one study

A simplified path from wood to glass; each step is explained, with its source, in the sections above.

Frequently asked questions

Why is French oak split and American oak sawn?

French oak has fewer tyloses, the balloon-like growths that plug the wood's vessels, so coopers split it along the medullary rays to keep the staves watertight. American white oak has more abundant tyloses and can be sawn. Splitting leaves only about 20–25% of a French oak log usable.

How much oxygen does a new oak barrel let into wine?

In a 2021 OENO One study of a new sessile oak barrel, 11.4 mg/L a year passed through the barrel, and 14.4 mg/L a year reached the wine once oxygen released from the wood's pores was counted; 46% of it arrived in the first three months. A laboratory comparison of 8 cooperage woods found French oak more permeable to oxygen than American oak in every case.

What does toasting change in a barrel?

Toasting heats the inner face and breaks down part of the lignin, cellulose and hemicellulose into volatile and non-volatile compounds, including lactones, that the wine extracts and that are associated with smoky, woody or vanilla aromas. It is also one of the factors that change the barrel's gas exchange.

Sources