Oak Beer in a Used Bourbon Barrel

Many microbreweries and some home-brewers age beer in used oak bourbon barrels. As would be expected, this form of “oaking” imbues beer with the distinct flavors of oak wood and bourbon, but as the beer rests in the barrels over the course of months or even years, it mellows and develops phenomenal complexities. Stronger beers, such as those with alcohol contents of nine or ten percent, generally benefit from longer aging periods.


  1. Acquire a used bourbon barrel. Used barrels can be ordered online or through homebrew shops. Distilleries may have used barrels available. Bourbon is whiskey, with a mash bill of at least 51% corn, made in the United States and aged in charred, new oak barrels. It's fine if the metal banding on the barrel is rusty, but the wood should not be overly deteriorated. There may be residual bourbon in the barrel. It's a good sign if there is, because the oak should stay wet in order to prevent shrinkage of the wood and resulting leaks. The barrel's bunghole should also be securely sealed with a rubber stopper, as this will help to ensure that the inside of the barrel has remained moist and free of external contaminants. A barrel with residual bourbon also probably won’t harbor a large amount of microbes because alcohol is antimicrobial, although wood will always harbor certain microbes that actually give oak beer desirable sensory qualities.
  2. Determine a safe, temperature controlled place to store the barrel. A cool basement with a concrete floor is optimal, as this will need to sit several months or years. There is always a chance for leakage, so make sure it's on a surface that can be cleaned.
  3. Brew enough beer to almost fill a bourbon barrel. Bourbon barrels have a capacity of {{safesubst:#invoke:convert|convert}}. If you're a home brewer, you'll most likely need to brew quite a few batches to fill one barrel. This is quite doable, however, since the barrel will be filled with fermented, uncarbonated beer. Just have your full carboys or conical fermenters ready when you're going to fill the barrel, or invite some friends to brew together.
  4. Drain off any residual bourbon. Invert the barrel and drain the bourbon through the bunghole. The residual bourbon will contain charcoal because the inside of bourbon barrels are charred. The residual bourbon will contain a fair amount of charcoal particles. Removing the residual bourbon serves to remove these charcoal particles, but you'll also end up with some bourbon that you can filter with a cheesecloth and drink or use as desired.
  5. Check the inside of the barrel. Use a flashlight to inspect the inside of the barrel for unwanted objects or damage.
  6. Secure the barrel on a stable platform. Put the barrel on a platform that, if desired, can be moved with a forklift or pallet jack, such as a small wooden pallet. Screw or otherwise fasten blocks to the platform that will keep the barrel from moving, but never drill, screw, or nail into the barrel itself.
  7. Fill the barrel with beer. Fill the barrel with uncarbonated beer using any means that you have available. Use a siphon, sankey-keg filling line, or other such means. Leave a little head space. Use a flashlight to monitor the fill level.
    • Be sure to sanitize the filling equipment, as you want to prevent as much microbial contamination as possible, even though the beer will become contaminated in the barrel to a certain extent.
    • Don’t be overly concerned with preventing oxidation, as the beer will oxidize to a certain extent while aging in the barrel (oak barrels are somewhat permeable to the outside air). However, it should be fine to purge the barrel with CO2 in order to prevent initial oxidation, and it's always a good idea to place the end of the filling tube at the bottom of the barrel to prevent splashing, which is a major cause of oxidation.
  8. Seal the bunghole with an airlock. Sanitize an airlock and a drilled rubber stopper, and securely set them in the bunghole. Fill the airlock with sanitizer so that the bunghole is sealed from the open air.
  9. Let the beer age in the barrel. The aging process can last from one month to over one year. If desired, take small samples with sanitized equipment during the aging process to determine when you think it is ready.
  10. Remove the beer from the barrel and package it. When the beer is ready to keg or bottle, siphon or pump it out and into the kegs or bottles. At this point it may be a good idea to purge kegs and/or bottles with CO2 to prevent additional oxidation and stabilize the beer. Also, be sure to sanitize the bottling equipment, as well as the kegs and/or bottles.


  • It may be advisable to check the barrel for leaks before filling it with beer, especially if the barrel is dry inside. As the barrel that was used was sealed with a stopper and still contained residual bourbon, the wood was still moist and therefore likely resistant to leaks. If the wood dries out, it will contract, thus paving the way for leaks. If the wood is dry, the barrel may need to be hydrated over a period of time with hot water. An overnight soak may be enough, but it may be necessary to soak it for about one week (change the water daily). However, it may then be necessary to sanitize the hydrated barrel with a solution of sodium metabisulphite and citric acid, as water is a source of microbes.
  • Oak intensity increases over time. Test along the way to make sure your beer isn't getting too oaky.


  • Carefully sanitize all equipment.
  • Never use sulfur candles to sanitize bourbon barrels if there is still bourbon inside. Bourbon is highly flammable.
  • Some oak is good, too much tastes like drinking wood. You're always better going with a little less oak flavor, especially if you expect friends to drink it.
  • Make sure all the beer is fully fermented before adding it to the barrel.
  • Never use a barrel with any signs of mold or fungus growing on the wood.
  • Store the barrel with a little sanitizer solution between uses.

Things You'll Need

  • Bourbon barrel
  • Rubber stopper
  • Cheesecloth
  • Flashlight
  • Screwdriver, screws/nails
  • Siphon, sankey-keg filling line, etc.
  • Sanitizing equipment
  • Airlock
  • CO2

Related Articles

You may like