The relationship between the type of barrel and spirit characteristics is something that most coopers and winemakers have been wondering about. If you want to understand the difference between a toasted and charred barrel, and how these affect the flavors of the beverage aged in them, this article is for you.

Toasted vs. Charred Barrels

Charring and toasting both give the barrel a brown color, but they differ in how dark the barrel gets and what kind of effect it has on the flavor of the final product.

Toasted barrels are made using a naked flame to gently toast the barrels. In this instance, the heat does not come into direct contact with the wood. Toasting is a slow process and it often takes 20 minutes for a barrel to undergo the toasting process. The determining factor for how long you toast your barrel depends on the flavor you want to be imparted into the spirit you’re making.

Toasting mellows the tannins in the wood and gives off sweet, spicy vanilla notes. Winemakers and coopers usually use the toasting process to make wine or lightly colored whiskey.

Charring is when heat is directly applied to the wood. This process of heating up barrels is often used for distilled spirits. But full-bodied red wines can also be aged in charred barrels. Once the barrel is charred, the wood acts as an activated carbon filter.

The carbon filter helps remove any sulfur compounds from whiskey to ensure a smooth final product. The reason why charred barrels are often used to make whiskey and bourbon is because of the dark, smooth and rich flavor you get from spirits aged in these barrels.

Toasted Barrels Explained

Oak is often used to make toasting barrels because it contains a compound called lignin. When heated, lignin gets broken down into vanillin. Vanillin is responsible for the rich vanilla flavor that you get from drinking spirits aged in toasted barrels.

The Toasting Process

To toast a barrel, an assembled oak wood barrel is placed on a heat source. The barrel is heated for 20-40 minutes depending on the preferred level of toast. The heat changes the chemical makeup of the wood and brings out different flavors and aromas. As mentioned, the duration at which the barrel is toasted determines the different flavors you can achieve from the level of toast. Three levels of toast can be achieved through toasting. These include:

Light toast: This type of toasting involves toasting the barrel for a short amount of time (often 20 minutes). The method can be used for barrels that are going to be filled with wine or other spirits where you wish for a lighter-colored whiskey but don’t want any intense flavor imparted from the wood.
Medium toast: Medium toast barrels are used for red wines and spirits that require some color development and more flavor than a spirit aged in a lightly toasted barrel.
Heavy toast: When you think about what whiskey tastes like, you probably think about caramel and vanilla flavors, right? This is because heavily toasted barrels give off those flavors when they’re used for aging whiskey.

The heavy toasting on the staves releases these scents during the distilling and aging processes because they contain sugar and oils that react with oxygen during the distillation and aging processes.

What flavors and Congeners Do Toasted Barrels Impart (The Science)

The flavors and congeners imparted from toasted barrels depend on the chemical reactions of the wood when it’s heated.

The following compounds are responsible for imparting flavor:

1. Hemicellulose

Hemicellulose is a polymer (substance consisting of large molecules or macromolecules) found in plant wall cells and contains multiple sugars. These sugars include glucose, xylose, and mannose. When the heat source is activated, the sugars get broken down and provide notes of cinnamon, almond, maple, butter, and coconut.

2. Lignin

Lignin is also another polymer and it’s responsible for the sweet and spicy aromas we find in spirits. Lignin also acts as a binding agent of wood cells. When heated, lignin breaks down into vanillin and imparts a vanilla flavor when absorbed by the spirit.

3. Tannin

While tannin does not impart noticeable flavor to spirits, it does, however, give off subtle cooked apple flavors. Tannin plays a major role in the oxidization process during the aging process.

How Does The Toasting Duration Affect The Flavor?

The flavors secreted from the toasted barrels depend on the amount of time the wood is toasted. The longer the toast, the more intense the flavor. Light toast often takes 25 minutes exposed to flame and heavy toast takes approximately an hour. Here are the different toast levels and the flavors they impart:

Light toast: Vanilla, coconut, caramel, cinnamon.
Medium toast: Honey, coffee, cocoa, vanilla, toast.
Heavy toast: Espresso, smoke, toffee, butterscotch, molasses, and vanilla.

What Are Some Examples of Spirits Aged In A Toasted Barrel?

Light-colored and sharp-tasting spirits are often aged in toasted barrels. Examples of these include:

Wine
Whiskey
Sherry

Charred Barrels Explained

Different char levels produce different flavors. While a higher level of char does produce a richer, smokier whiskey or bourbon, it does not mean it’s better than the lower levels of char.

The Charring Process

The charring process involves directly heating the barrel at temperatures of between 500-600 degrees Fahrenheit for 30-60 seconds. The barrel is then extinguished and sprayed with water. The char level depends on the flavor of whiskey you want. These levels include:

Level 1 char: This level is just slightly above a heavy toast. The level is ideal for quick-aging bourbon because it does not impart as much woodiness into the spirit compared to other levels of char. To achieve this level of char, the barrel is heated for 15 seconds.
Level 2 char: This is one of the less utilized levels of char among distillers. The flavor of this char is a subtle caramel. Level 2 char is achieved by burning your barrel for 30 seconds.
Level 3 char: A level 3 char is achieved by burning your barrel for 35 seconds. It’s a level that’s commonly used when making American bourbons and whiskeys. The end result is a spicier and earthy flavor and a deep brown color.
Level 4 char: A level 4 char is achieved after 55 seconds of heating the barrel when the barrel begins to crack and peel. This level provides an intensely deep brown color and an enhanced level of spicy, smoky, and sweeter flavor. The purpose behind this level is to extract as much flavor as possible from the wood.

What Flavors And Congeners Do Charred Barrels Impart (The Science)

Here are compounds responsible for imparting flavor to charred barrels:

1. Lactones

Lactones (often found in oak) are responsible for releasing coconut and woody notes of Bourbon.

2. Vanillin

Imparts a vanilla flavor.

3. Eugenol

Imparts spicy flavors such as cloves.

4. Furfural

It releases aromas of almond, butter, toffee, and caramel.

What Are Some Examples of Spirits Aged In A Charred Barrel?

Deep brown and intensely flavored spirits are aged in charred barrels. These include:

Whiskey
Bourbon
Scotch
Tequila
Vodka
Rum
Some Red Wines

Toasted Or Charred-What Is Best?

Both types have their advantages. So the answer is, it depends on what you’re looking for. If you want something bold and spicy with a hint of smoke, then charred is the way to go. However, if you prefer a more subtle oak flavor that doesn’t overpower the taste of your whiskey, then toasted is probably best.

Frequently Asked Questions

What does toasting do to the barrel?

The process of toasting caramelizes sugars in the wood, which helps to impart flavor. The degree of toasting is determined by how much heat is applied to the barrel. Some barrels will be lightly toasted, which will not add much flavor and may even remove some from the spirit. Other barrels are heavily toasted, which imparts lots of flavors into the spirit.

Are bourbon barrels toasted?

According to the Alcohol and Tobacco Tax and Trade Bureau, bourbon barrels have to be charred. The reason why charred barrels are preferred over toasted barrels is because no flavoring, additives, or coloring should be added to the spirit. The process of charring allows the pores of the wood to open up, so it’s easier for the bourbon to extract vanilla, toffee, and caramel flavors from the wood. These are the flavors that distillers (and bourbon drinkers) know and love.

Are Scotch barrels toasted?

Scotch barrels are toasted and charred. Most distillers prefer an added dimension of flavor. So, by toasting and charring the Scotch, it is better able to absorb the flavors of vanilla, coffee, and spiciness.

Conclusion

So, which kind of barrel should you use? Well, it all depends on what you’re trying to achieve. However, if you want your whiskey to be smooth and complex rather than sharp and ashy, then charred barrels may be the way to go. If you want to make something unique, try a combination of charred and toasted barrels for an entirely new taste. You’ve got nothing to lose.

Sources:

Barrels and Aging, Distilling 101

Toasted vs. Charred Barrels (Explained)

Toasted vs. Charred Barrels