What's an oak barrel and why most alcohols still mature inside them
For thousands of years the best way to store any type of liquid was in a wooden cask also known as a barrel. These barrels protected the contents from pest and from spoilage and their round shape made them strong and easy to move.
These barrels where often burnt(charred) on the inside between uses to eliminate any leftovers from the prior contents. Once that charred barrel was filled with alcohol is when the modern drinks we all know started to develop. Depending on the type of alcohol sugars -corn,potato,barley,grapes- it would interact differently with the charring and give whole new sets of flavors.
Oak Barrels are so important during the aging of liquors that there would be no whiskey without a barrel, no Gold tequila without a barrel, even most wines would taste much different if they had not spent some of their life in a barrel. People also use barrels of non-alcoholic items including vinegar and hot sauce, to name a few.
Step #1 - Blow into the cork hole on the top (optional) This may sound silly, but the best way to see where any super fine gaps between the wood might be is to blow into the barrel. When you create this positive pressure on the inside, you will be able to hear where the air is escaping from the barrel. If you hear air slightly coming out of it, that is fine and completely normal. The wood will swell noticeably once wet. However, the outside will be dry and only the inside of the barrel that holds the liquid will swell. This step is optional, but it is a convenient way to tell where the water will drip from in the initial fill of water. One important note- If you barrel has been left exposed to the air with no contents it will shrink by up to 10%. This is not desirable and should be avoided because it will make it harder and take longer for the barrel to seal when you are ready to use it. The metal hoops might even pop off if left dry long enough. If you’re not ready to use it yet or you need to offer it as a gift, wrap it back up in the shrink wrap/box it was shipped in. If you don’t have that and want to keep your barrel in optimal condition for when you are ready, leave it ¼ to 1/3 full of water while in storage.
This one’s pretty simple. Fill the barrel at least 50% with room temperature water and let it sit. Once you do this, the wood will start to swell and you will notice any potential leaks. Most of the time, a simple paper towel placed underneath will be fine. However, you may want to put it in the sink if you feel it’s leaking a bit too much. Let it sit for 15 minutes or until the leaks stop, whichever comes first. Whether the barrel was made 200 years ago or is one of ours and was made a couple weeks back, leaks are to be expected with every wooden oak barrel. Once it is all sealed, pick it up with the cork on, roll the water on the inside from one side to another or give it a light to moderate shake. Make sure that the water covers every part of the barrel on the inside. This is done to both ensure there are no additional leaks and to scrub off any potential wood chips on the inside before draining the water. Once you have given it a good shake, let it sit for a few additional minutes and make sure there are no additional leaks. If leaks persist for a few days, you can seal them by melting candle wax and placing the melted wax over the leaks. The wood must be dry for the wax to adhere and seal the barrel. Never place wax on the inside of the barrel as it will contaminate wine or liquors stored on the inside.
Once the wood has sealed, it’s time to drain the water. Over a sink, or if you have a bigger barrel outside, roll the barrel so the cork hole is pointing downward and remove the cork. Once removed, the water will start to flow. With the cork removed, open the spigot. This will allow air to flow in as the water flows out. Once clear of the water, you can either fill with your alcohol/spirits or repeat the process again if you feel it needs additional cleaning. Make sure you are comfortable with the barrel sealing fully before adding your contents. It’s always better to let it sit for a few extra hours or a day after it seals, than to add your drink early and let some of the contents spill out.
Now that your Golden Oak Barrel is sealed nice and tight and it’s all cleared out, it is time to fill it with your favourite spirits. As you fill it through the top cork hole, you want to make sure the spigot is closed (not pointing straight away from the barrel). Once filled with your spirit and any other ingredients, go ahead and put the cork back in the top to seal it. Note: If you pour something in that releases gas when aerated (like wine), then you need to leave the cork off the top for a while. If you don’t, the pressure will push it outward and may cause the barrel to leak. That’s it, you’re done! Your spirit is ready to drink at any time. Simply pull it over to the edge of a counter, remove the cork from the top (this is so it will flow), put a glass under the spigot and open it. You will have a refreshing glass of whatever amazing spirit you put in there.