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Oak, Bourbon, and Homebrew Volume II – Barrels

March 28th, 2013 // By // The Brewery // View Comments

Learn how to oak age your homebrew in a bourbon barrel

This is my second entry in a series of posts about using oak in home brewing. My first post on the topic focused mainly on using oak cubes and chips, but for this one, I’ll talk about my experience using an actual barrel.

My experience using barrels started when Great Fermentations got a hold of a once used Templeton Rye barrel, which ultimately started our whole barrel program here. If you were able to try our first beer aged in the barrel (rightfully named Temple of Rye) then you know the results were great. Our second beer is in the barrel right now, and based on the success of the first round, we’ve got high expectations. More on our barrel program soon in another post, but in the meantime here is a picture that correctly shows the power that beer from a rye barrel can have on someone:


Anyways, armed with my experiences from using our barrel at work, I was keen to give it a shot at home, and jumped on the opportunity when Great Fermentations got in some 15 gallon used Rye barrels from Dad’s Hat Rye out of Pennsylvania. My experience though was not 100% transferable, as smaller barrels have their own set of challenges.

It’s important to understand that smaller barrels have a much higher surface to volume ratio than their full sized counterparts. In other words, the more surface area of wood in contact with a smaller volume of beer (or wine, whisky, rum, etc), the faster the exchange of flavors will take place. Still with me? It’s similar to using oak chips vs. cubes; the process will happen faster with the chips that have the larger surface area.

Besides pulling out all the oaky goodness (as well as spirit flavor) faster, a larger surface to volume ratio also means that oxidation happens more rapidly, accelerating the aging process. In some ways this can be a good thing, but the downside is that Acetobacter, the acid producing bacteria that makes Flanders Red Ales so delicious (and vinegar so vinegary), really really likes wood and thrives in oxygen rich environments, greatly increasing the risk of infection.

Wax on, wax off (well maybe just wax on)…

You can’t do much to slow down the extraction of the oak and all it’s flavors, but there is a good, relatively easy way to slow down the speed that oxidation takes place so that it’s about equal to a full size barrel. You can ensure this by covering a certain percentage of the outside of the barrel using standard paraffin wax.

A 15 gallon used Rye barrel, with about 50% of the outside waxed

If using a 5 gallon barrel, you’ll want to wax all of the outside of the barrel, leaving the heads (the barrel ends) unwaxed. A 10 gallon barrel you’d wax about 75%, minus the heads, and for a 15 gallon barrel (the size of ours) you’d want to wax about 50%, minus the heads. The waxing process isn’t too hard. Paraffin blocks are available from most hobby stores, and I used a super high tech double boiler setup to melt it down :)

It's science!

Next, I used newspaper and tape to mask off the half of the barrel that I didn’t want waxed.

(compete crossword puzzle before masking barrel)

Then using a combination of an old beat up paintbrush I found in the basement and a scientific kinda “drizzle it on technique”, I gave my barrel a nice coat of wax. You probably should do this step outside or at least in the garage to avoid your better half’s wrath, but it was really cold in the garage that day and I can be sorta wimpy. Proper attire is also very, very important.


I would have preferred to take a propane torch to the outside of the barrel once it was waxed and pretty it up, but since this was a once used spirit barrel that still had quite a bit of alcohol fumes in it, I decided that it could wait. Once you get the barrel waxed up, there are a couple more steps to complete before you can just toss beer in the thing. I know, I know, but I promise it’s worth it.


If you ask five different wine makers and five different brewers that have a barrel program on the proper way to sanitize and prepare a barrel, you’re likely to get 37 different answers, at least one of them involving chicken blood at midnight. You can use ozone (fancy, expensive, and potentially dangerous), sulfite matches (great unless it’s a used spirits barrel, then you’ll blow yourself up), a number of chemical sanitizing solutions, boiling water, or water that’s hot enough to pasteurize the barrel. I chose the pasteurization method, filling the barrel up completely with 180° F water, and keeping it in until the temperature dropped to around 155° F before emptying it. Using this method also lets the barrel swell up and seal.


It’s important to understand that while any of the above methods of sanitizing will work, it’s virtually impossible to sanitize a barrel completely, and eventually the barrel will go sour. Never letting the barrel sit empty will certainly help, but instead of dreading this, embrace it and use it as an opportunity to brew some awesome sours at home.


Especially for the larger barrels, it’s important to figure out where you’re going to park the thing because once it’s full, there’s no moving it. A full 15 gallon barrel is going to weigh around 150 pounds, so choose wisely. Ideally you want it to be stored at cellar temp (roughly 55-62° F) but don’t fret if that is unachievable. A basement works just great, and even if that’s not possible, room temp will be fine. Next you want to be sure that it is elevated enough so that you can siphon it to your keg/bottling bucket when you’re ready. Lastly, the barrel needs to be on its side; don’t sit it on one of its ends. For the height and sideways storage requirements, commercial barrel stands are available, but they’re expensive, so I opted to make my own and a stand that was tall enough I could siphon out of it with gravity.


Add the beer and kick back for a few months

Once you’ve got a spot it’s merely a matter of siphoning the beer into your barrel, using whatever method works for you. Mine was a bit on the shady side.

leaning tower

The smaller the barrel, the quicker the beer will develop the characteristics from the barrel that you’re after, so be careful not to overdue it. For a 15 gallon barrel, 3-4 months will probably be the sweet spot, but it depends on the base beer, the barrel you’re using, and your personal preferences. Like I said in my last post, taking regular samples is key.

Barrels take some work to use at home, but they’re a fun project, and the end results can be really magnificent. As always, if you have questions, contact us at Great Fermentations.