Wooden Barrel Care: How to Swell a Dry or Leaking Barrel

Wooden whiskey barrels often have the most unique flavor profiles. Many major distillers use aged wooden barrels to create the richest, most distinctive tasting spirits. If a wooden barrel used for distilling whiskey, bourbon, scotch, or another specialty liquor encounters a leak, don’t automatically replace it. The barrel might need a repair or adjustment and can be reused again and again.

Patching a Leaky Wooden Barrel:

Tighten the Barrel Rings

The rings on a barrel can loosen over time. To lighten these, gently tap the rings back into a snug position using a mallet or hammer.

Use Barrel Sealant or Wax

Rub dry wax or drip melted wax into the leaking area. You can purchase these sealants online, or there are also DIY sealant options. One option is to fill the area with a ration of 1:4 distilled water and unbleached flour, then go over the mixture with a blow torch to cure and seal it.

Reeds, Straw, or Toothpicks

Find the leak and gently push in a toothpick, piece of straw, reed, or small piece of wood to plug the hole. Sand down any excess. This method can make the leak worse if done incorrectly, so be sure to use caution.

How to Swell a Barrel

If these methods of patching a leak do not succeed, it’s time to try swelling your barrel. Knowing how to do this can save you time and money. Some barrel retailers will recommend that you swell a new barrel right off the bat. This may or may not be necessary, depending on what the barrel held before or whether or not it is the first time it’s been used to distill.

There are three main options to swell a wooden barrel:

Head Swelling

This method is often the most successful. Stand the barrel vertically on one head. Fill the top head to the top ring up with hot water. Let the barrel sit overnight. In the morning, add more water and watch for air bubbles. If no bubbles are present, flip the barrel over and repeat the process. This method is great for swelling the joint between the heads and the staves, which is the most common area for leaks. 

Swelling the Inside

Lay the barrel horizontally with the bunghole facing up. Fill 1/3 of the barrel with hot water for two hours. Periodically roll the barrel back and forth to coat the inside of the barrel. Add another 1/3 of water and check for leaks. If still leaking, allow the barrel to sit for an additional 1-2 hours. Using this method, you should fill the barrel with your favorite liquid immediately after swelling is complete.

The Steam Method

Once again, begin by laying the barrel horizontally with the bunghole facing up. Using a steam generator, fill the barrel with steam at least 212° F. Continue pumping steam into the barrel for at least ten minutes. If the barrel is very dry, it may take longer to tighten up. Once tightened, drain any water and fill the barrel with cool water to check for leaks.

Swelling a New Barrel

For a new barrel, it is common to swell it before use to fill existing leaks. To do this, fill the barrel full of hot water and keep it full until any leaks stop. This can take anywhere from an hour to a week, depending on the size of your barrel.

The Barrel Mill creates premium oak whiskey barrels for quality, consistency, and repeatability in every batch. Each of our barrels is expertly handmade and charred based on your needs. Contact The Barrel Mill to learn more.