How To Age Whiskey (Complete Guide)

Image of diy distilling how to age whiskey the complete guide to oak barrels and aging whiskey

Aging whiskey is one of the most important aspects of this wonderful elixir. It’s the bridge between an okay-tasting whiskey and a perfectly smooth, intensely flavored drink. Whether you want to age your own whiskey, or just like reading about aging whiskey, here’s everything you need to know about the art.

How Do You ‘Age’ Spirits? (And Why)

Spirits are aged in barrels. The barrel is often cured using warm water before adding the spirit to it. Once cured, you pour your alcohol into the barrel and allow the chemical compounds from the wood to impart flavor into the spirit. While the alcohol stays in the barrel, the spirit takes up the flavor and color from the wood. After a good three-plus years, you’ll be left with a flavorsome drink that gives off notes of vanilla, caramel, or butter (or a combination of all three and more). 

When spirits leave the still, they come out clear. To add color to them, they have to be aged. But, aging isn’t only about adding color to your beverage, it’s also about adding a dimension of flavor and increasing the quality of the alcohol. The flavors you find in aged spirits can be anything from sweet and spicy, to bitter and smoky.

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How Does Wood Affect The Taste Of Whiskey?

Wood is responsible for a large percentage of the taste of a finished product. Wood eliminates the harsh chemicals found in distilled spirits and adds a myriad of fantastic flavors. When wood comes into contact with the spirit, it leaches tannins and sugars that combine with the whiskey in the barrel to give us the flavor we know.

Why Use Oak? What About Other Woods?

Oak is used to age whiskey because it contains tannins. Tannins are compounds that ensure oxidation during the aging process. Oak is also watertight, yet porous enough to allow enough room for the spirit inside to absorb compounds from the wood. Taking the legal aspect into account, the US federal regulations require oak to be used for all whiskies. It’s easier to bend the staves of oak wood, it’s breathable and enhances the flavor.

Woods like maple, cherry, and hickory can also be used. But these woods only serve as finishing casks. Avoid wood such as pine because the sap travels in the veins of the wood. When alcohol is added, the sap interacts with alcohol and affects the flavor of the beverage. 

What’s the best oak for aging whiskey?

As mentioned earlier in the post, oak is often preferred in aging whiskey. But there are different types of oakwood and they all impart different flavors. Here are the best oaks for aging whiskey.

1. American Oak

American (white) oak is best for aging bourbon, whiskey, and scotch. It has a wider grain and often produces a well-rounded whiskey. It is responsible for the aromatic notes of vanilla, coconut, and caramel that you often find in your whiskey.

2. French Oak

Also known as European white oak, French oak has a finer grain and is rich in vanillin. This oak typically has a higher amount of tannins, but it produces a much smoother whiskey because of the fine grain. It imparts flavors of vanilla, cedar, and caramel. 

3. Hungarian Oak

Hungarian oak often produces a more intense oak flavor than that of American oak. When you drink whiskey aged in this type of wood, you can pick up hints of chocolate, black pepper, espresso, and vanilla.

4. Mongolian Oak

Mongolian oak, also called Japanese Oak or Mizurana, imparts notes of sandalwood, spicy rye, and oriental incense.

Charing vs. Toasting

For a whiskey to absorb any flavors from the barrel, the barrel has to be heated in some way. That’s where charring and toasting come in. Toasting and charring is the process of heating oak barrels to activate compounds found in the wood. This way, the spirit is better able to absorb flavors imparted by the wood. These compounds responsible for imparting flavor are: 

  • Hemicellulose- A polymer found in plant wall cells and contains multiple sugars. When the heat source is activated, hemicellulose gets broken down and releases sugars for the whiskey to absorb. This chemical is responsible for notes of cinnamon, almond, maple, butter, and coconut.
  • Tannins- Tannin plays a major role in oxidation during the aging process.
  • Lignin-  Acts as a binding agent of wood cells. When broken down, it imparts a vanilla flavor when absorbed by the spirit.
  • Vanillin- Imparts a vanilla flavor.
  • Lactones- Responsible for releasing coconut and woody notes.
  • eugenol- Imparts spicy flavors such as cloves.
  • Furfural- Releases aromas of almond, butter, toffee, and caramel.

Here’s an explanation of the differences between toasting and charring. For a more in-depth compression of toasting versus charring, you can read this article.

Toasting Explained

Toasting is the process of gently heating a barrel using a heat source. Often, a furnace is used when toasting a barrel and the heat does not come into contact with the barrel.

There are three levels of toast that can be achieved when toasting barrels. These include:

  • Light toast– This level of toast imparts flavors of vanilla, coconut, caramel, and cinnamon. 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– A type of toast used to develop more complex flavors in a spirit. A medium toast lends flavors of coffee, honey, cocoa, and vanilla.
  • Heavy toast– A heavy toast imparts flavors of espresso, smoke, toffee, and butterscotch.

How long should you toast oak for?

Depending on the temperature you’re using, you can toast oak for 2 to 6 hours. For a visual presentation of the different temperatures for different flavor levels, have a look at the image below. The temperatures below give you an idea of how high you should set your toaster (or oven) at to achieve different flavor profiles, starting with an oaky flavor.

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Oak Toast Chart Source:

Charing Explained

Charring is a more intense way of heating a barrel. The process is achieved by directly heating (burning) the inside of the barrel. Barrels are usually charred to intensely break down the compounds of the wood, so the finished spirit has a deep brown color and more caramel, vanilla, and coffee-like flavor. The four levels of char are:

  • Level 1- This level 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 -The flavor of this char is subtle caramel. Level 2 char is achieved by burning your barrel for 30 seconds.
  • Level 3– 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– 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. 

How To Char Oak For Whiskey Making

When you’re ready to oak your whiskey, get yourself some untreated (no chemicals added) American white oak. Ensure your oak is well seasoned. Seasoned oak has been cut and left to sit outside for one to three years. 

Cut your wood up into manageable sizes (preferably 0.7 inches X 0.7inch) that’ll fit in a jar. You can use a blow torch or char it on a barbeque stand for 15 to 55 seconds depending on the char level and flavors you’re looking for. 

Aging With Barrels:

53-gallon barrels are often used in aging because they have a bigger surface area which allows for oxidation to take place, which in turn provides intense flavor for the whiskey.

The following pros and cons of aging with barrels are based on large barrels.

Pros of aging with barrels

  • It allows spirits to age well because of their size.
  • Oxidization is controlled.
  • It adds a combination of tasty flavors when compounds like vanillin, lactones, and eugenol are broken down.
  • Protects spirits from direct sunlight.

Cons of aging with barrels

  • New barrels are expensive. They can cost up to $1000.
  • Barrels take a long time to impart flavor to spirits.
  • They take up a lot of storage space.
  • When not cured properly, your spirit can leak, which will be a waste of money and ingredients.
  • They are labor-intensive. You’ll need to constantly stir the contents in the barrel to assist with the process of aging.

How To Age Whiskey In A Barrel.

Before you age your whiskey, you’ll need to cure your barrel. Curing prevents spirits from leaking and it’s done by adding warm to hot water into the barrel. The process of curing often takes 2-7 days.  

How to cure the barrel

  • Fill the barrel with hot water from the tap and cover the filling hole at the top.
  • Let the water sit for 48 hours.
  • Monitor the level of the water, and refill the barrel with water until it reaches the top of the barrel.
  • Water will leak, but continue filling the barrel with water until the leaking stops.
  • When the leak has stopped, drain any water left in the barrel.
  • Pour warm water and rinse the inside of the barrel. Spill out the water and carry on the process of rinsing until the water drains clear. 

How To Age Whiskey

  • Fill the barrel with a 55% ABV spirit and allow the aging process to begin.
  • Monitor your spirit every 2 weeks and rotate your barrel every month to help blend the whiskey.

NOTE: Store the barrel away from direct sunlight.

How Long To Age For

Aging can take anywhere from a couple of months to several years. It all depends on your taste preference. You will need to taste your spirit every few weeks until it reaches your desired taste. When you’re satisfied, pour the spirit into a glass bottle and store it. 

The best barrels for aging whiskey

Here are four of the best barrels for aging whiskey.

1. Golden Oak Barrel With Brass Hoops

The Golden Oak barrel has a medium charred interior which is great for aging whiskey. It is a 2-liter barrel that allows you to age your whiskey within 90 days because of the quality of the wood. The best thing about this barrel is that it does not take long to cure, so you can start your aging process as soon as you get your hands on it.

2. Thousand Oaks Barrel

The thousand oak barrel is a medium charred barrel that can hold up to 5 liters of spirit. It has a natural finish and produces the best quality flavors.

3. Personalized American Oak Whiskey Aging Barrel

This is a high-quality handcrafted barrel. You can have your name engraved on the barrel, which adds a personal touch to it. The interior is medium toast charred, and the spirit aged in the barrel gives beautiful notes of vanilla and caramel. 

4. Sofia’s Findings Custom American White Oak Aging Barrel

This budget-friendly barrel is very similar to an American oak whiskey barrel. Although the exterior is not as appealing as the barrels mentioned above, it’s still a good quality barrel with size options ranging from 1 to 20 liters.

Aging With Inserts:

Oak inserts can be used in place of barrels to age whiskey. They are usually made from parts of the wood that are not used to make the barrel. Inserts are naturally seasoned before use to remove any moisture from the wood. 

Similar to barrels, inserts are toasted or charred to further activate the chemical compounds found in the wood for optimum flavor. Inserts come in various forms and these include:

  • Chips
  • Cubes
  • Staves
  • Spirals
  • Powder

Pros of aging with inserts

  • They impart flavor to spirits much quicker than barrels.
  • Affordable way of aging spirits.

Cons of aging with inserts

  • Staves and spirals usually have a larger surface area, so it takes a while for them to impart flavor.

How to age whiskey with inserts

The more inserts you use, the more flavor you’ll get that mimics commercially made whiskey. First, you’ll get some American or French oak. If you’re new to aging with inserts, it’s best to use tried and tested wood such as American and French oak. Follow these steps to age your whiskey using inserts:

  • Pour 1 liter of 55%ABV spirits into a glass jar.
  • Add 20-30 grams of oak chips into the jar. If you’re using cubes, add 8 cubes into the jar.
  • Cover the top of the jar with a coffee filter and keep the filter in place using an elastic band.
  • Taste the whiskey every two weeks until the desired flavor is achieved. Aging can take up to three months. 
  • When the spirit tastes as desired, strain the whiskey into a glass jar. Use a cheesecloth or coffee filter for straining to prevent chips from entering your finished product.
  • Seal the jar and store it in a dark, cool room.
Image of using oak inserts to age moonshine

How long to age for

Aging spirits using inserts takes a relatively short time compared to aging in barrels. It can take anything from 2 months to 9 months to get a fully flavored finished drink. The more chips, spirals, or cubes you add, the faster the aging process.

Image of diy distilling aging whiskey on oak staves

The best oak pieces for aging whiskey 

1. American Oak Cubes

American oak is the most popular oak used when aging whiskey. The cubes release aromas faster, so they often need less contact time with the spirit.

2. French Oak Chips

French oak has more flavor compounds than American oak. It imparts flavors of cinnamon and cloves.

3. Hungarian Oak Cubes

Hungarian oak gives off more intense flavors. You can expect to find a combination of espresso, vanilla, and black pepper.


Aging whiskey is an art and science. There are certain rules you must follow and certain steps you can never skip. If you want to achieve greatness in your whiskey, use these tips to start aging today! Whether you’re a whiskey guru or a complete noob, these are the key factors to consider when aging a whiskey. Hopefully, the information can help you age a good quality bottle of whiskey worth sharing.


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