Since 1995 (or, more arguably, 1992), the build up from a slow burn to the craze that has swept the industry of aging beers (namely, imperial stouts) in used spirit barrels has been a thing.
It’s almost impossible to avoid brewing them in some capacity as a professional brewer and as the delight from consuming them trickled into the homebrew realm, it has slowly become a rite of passage for the hobbyists everywhere.
Some of the challenges of this endeavor, however, come mostly from the cost and the scale – firstly that spent barrels are now highly coveted, thus driving up the price, secondly being that most real barrels are going to be 55 gals, unless you get lucky enough to snag one of the few 5 of 15 gallon varietals that pop up every once in a while.
The bragging rights of having one’s own barrel is nice, but for people who are limited by costs, scale, or space, the laments are strong.
Homebrewers, being the innovative types that they are, have appropriated and adapted these techniques. Soaking oak chips (or staves, spirals, cubes, etc.) in the desired spirit is a solid compromise for achieving the desired effect of the barrel, without any of the aforementioned commitments. But, as with many of the tricks of the trade, there’s a lot of nuance.
Chips have a propensity for getting super tannic and oaky, due to the large jump in surface area ratio and contact compared to a real barrel. It requires far less time to get the desired results, and can often lead to too strong a taste, at times, or not quite mimicking the flavors of a barrel. There are, however, some steps that you can take to rectify this, though.
Over the years, I’ve managed to hone my oak game. For that, it’s important to understand why and how the oak works the way it does.
Origin, Roast, and Flavor
From the first step, there is the initial hurdle of the origins of the oak. Not surprisingly, there is some different flavors that appear depending on the countries where the oak comes from. The main three sources are going to be American, French, and Hungarian, each with their own nuances.
Now, part of the trick to fully utilizing the wood is knowing what spirits you’re going to be using with them (or, if you just want straight up oak, then fuck this part).
Bourbon is specifically aged in first-use, charred American white oak barrels, as per the regulations. Many wine barrels are made from French oak. Hungarian oak is also common for wine barrels, but the oak itself has an even tighter grain than French oak, which loans itself to adding more delicate aromas and flavors to the wine and is perceived as being “more gentle”.
It’s worth noting that, even within a smaller acreage, there can be distinct variation between trees. It’s pretty difficult to even have consistent flavors just from one plot of land, let alone nationally, so these tasting notes are a little loose.
But, as a quick cheater idea, it’s still nice to match your wood to the style of spirit you want – American oak for bourbon or whiskeys, French or Hungarian for wines, etc. From there, it becomes a bit of a game for trying to match flavors to spirits. If American oak gets the slight botanical flavors at a lower roast, pairing that with gin may be more beneficial than going with the spicier European varietals. If you were thinking rum, then the contrary might be more what you want. This shit has got layers, like an ogre.
Roast and Toast
The second most important point to oak is going to be the roast. While there may some subtle differences in the wood by the region and country of origin, the most important part of the manufacturing process is actually the treatment of the oak through the processes of kilning and charring.
Charring is simple enough to explain. You’re literally burning the shit out of the inside of the barrel. That’s partly for sanitizing, but you’re also pushing the barrel through some chemical reactions. A lot of it is caramelizing the sugars in the wood itself through Maillard’s reactions, similar to kilning Cara/Crystal malts. That’s part of the reason that bourbons can taste so strongly vanilla forward compared to scotches, even though they may have a shorter contact time with the barrel (i.e. 2-3 years vs. 12-15). The charring and use of a fresh barrel also imparts a heavier color to the bourbon/whiskey than an uncharred barrel, but a spirit will inherently be darker the longer it sits in the oak.
Beyond that, the actual kilning, or toasting, of the wood also imparts dramatic flavor differences. The darker or lighter the toast, the more Maillard’s reactions happen, imbuing different flavors. I have a nice graph for explaining the different flavors you get from kilning/baking the oak at different temperatures or lengths of time to get the colors, but I have no idea how old this bitch is, because the image quality is absolute shit.
As you can see, there are different flavors that appear at different donenesses. The darker you go, the darker the flavors. Makes sense, right? Burn the fuck out of it, of course it’s going to taste like burnt shit. Personally, I find a sweet spot for shooting for a lighter toast, but some people might want the heavier tone, which would marry itself well into darker beers.
Color and Other Woods
Now, this is a slight digression, but some people more knowledgeable in wood might start asking “Why is it always White Oak, and not Red Oak, Black Oak, Pin Oak, Bur Oak, etc?”
White oak is physically unique as compared to other woods in its cellular structure. White oak has occlusions inside its cellular structure that makes the wood not porous length wise while remaining porous laterally. Red and other oaks do not have these occlusions. During barrel fabrication, these wood cells are opened which allows the liquid to enter the cells. Because of the cellular occlusions, the liquid does not soak through the entire barrel. Theoretically, you can take two pieces of oak in thin “straws”, one red and one white, and if you hold one end under water and blow on the other, you can make bubbles with the red oak stick but not the white.
There may also be some questions about other woods. Historically, other wood types, including chestnut, pine, redwood, and acacia, have been used in winemaking. However, none of these wood types possess the compatibility with wine that oak has in combining its water tight, yet slightly porous, storage capabilities with the unique flavor and texture characteristics. Chestnut is very high in tannins and is too porous as a storage barrel and must be coated with paraffin to prevent excessive wine loss through evaporation. Redwood is too rigid to bend into the smaller barrel shapes and imparts an unpleasant flavor. Acacia imparts a yellow tint to the wine. Other hardwoods like apple and cherry wood have an off putting smell.
There are certainly breweries that use much less conventional woods. I know for a fact that Hardywood Brewing uses poplar wood for aging their Hoplar IPA. I’d also be remiss to not mention Dogfish Head’s Palo Santo Maron. That being said, I still totally want to make a cigar beer with smoked malts and age it on cedar.
Step 1: Making the Vessels
After all is said and done, custom making your own oak to suit your purposes is actually stupidly easy.
Yeah, you can just buy an oz or a pound of oak chips from your LHBS store, soak them in the drink, and toss them in, but if you want specific flavors and a high level of control, then making your own is your best bet.
Finding American white oak is not exactly a crazy challenge. You can walk into most hardware stores, like Lowes or Home Depot, and find it. I’d recommend trying to find a specialty wood store that specializes in more exotic woods, since they might be able to have some higher quality, but I know that these are few and far between these days. The most important part of this step is that you need untreated wood. It should go without saying that chemicals are bad, mmkay. You don’t want sealants and the like, as it would not only taste bad, but could also have actual issues with making you sick.
At most, you might need a boardfoot’s worth of the wood. More than likely, they’ll be willing to cut it down in the store for you, especially if you don’t have access to the tools or a wood shop personally. They most likely will not want to cut it into super small pieces, like 1″ cubes, but if you ended up getting 1″x 1″x 6″ staves, that’s a lot more doable.
A point that is important to make now is surface area. They more surface area, the more contact the beer makes with the oak, the more flavors the beer can/will extract from the wood. That’s easy math. So, despite being the same amount of wood, six 1″ cubes will have more surface contact compared to a 1″x 1″x 6″ stave, even though they are volumetrically the same.
Ultimately, this is going to be more of arguments of function and preference. If you want flavor to be imparted faster, then you want more surface area. If you want shapes that are easier to work with, then you want something larger. Honestly, the most efficient shape for combining surface area is a spiral, but those are a bit more complicated to make at home. For all intents and purposes, cubes and staves work just fine. Another thought is that smaller pieces are easier to get out of carboys. Unless you have one of those big mouth jawns, getting out a long stave can be a real pain in the ass. Chips and cube can get dumped out relatively more easily. Chips, overall, are a fucking mess, especially with narrow mouthed carboys, since they can’t really get bagged up. Dem brew buckets are gonna be juuuuuust fine with loose chips or bagged.
I typically opt to do staves, but that’s because I do have a big mouth boy. I can just reach in and grab them. In the past, I used to do oak cubes.
Freshly shorn off of the wooden teat, this bad boys are raw as fuck and need a good deal of TLC to make them more usable.
Granted, you don’t need to do anything else really if you want the super white oak flavor (think that lightly vanilla and dilly tone in Cigar City’s White Oak Jai Alai), but for any other flavors to shine, there’s still work to be done.
Step 2. Pyromania
No, I’m not talking about the sweet Alan Parsons Project jam. I’m talking about old school Boy Scouts levels of burning shit. Remember that video I linked earlier about charring the inside of a barrel? Totally doable at home, although decidedly less cool. Easiest method is just going to be to spread out all your little oak buddies and torch ’em. Literally.
Typically, I do this on an aluminum foil lined baking sheet. This is also prepping for a step in the future, but it also serves the purpose of helping deter you from burning everything else and not putting your beautiful oaky babies on the dirty, dirty floor.
Take your shit outside, light up your torch, and let it rip. That’s pretty much it. The degree of char you want is up to you. The darker you go, the more vanillin compounds you’re going to make, and the heavier flavor will end up in the finished product. That being said, you probably only need to really char one side. I mean, who am I to tell you not to char everything, if your heart so desires, but you might want to rein it in a little bit on this one, firebug.
As to the actual degree of the charring, I recommend going to the point where you have successfully lit it on fire, like it will keep going if you remove the torch. You should get a fair amount of bubbling/cracking/texture on the wood, but if you start getting that rustic ass grey, you might want to stop.
Step 3. Astringency Control and Sterilization
Tannic. It’s a word that some pretentious tickers like to casually throw around when they huff their own farts and sip on their precious 2 oz. pour of some rare lambic at a bottleshare. It’s also typically given a slightly negative connotation, because you expect some tannic notes in oak aged beer, but if it is too strong, it can be derisive and off-putting.
Let me back up real fucking fast, though. What’s a tannin?
A tannin (or tannoid) is an astringent, polyphenolic biomolecule. Fancy lingo aside, it’s a naturally occurring chemical compound that contributes astringent, bitter flavors. Not only are they inherently found in wood, but also fruits, nuts, and spices, like pomegranates, grapes, hazelnuts, walnuts, and clove.
Unless you really like sucking on wood, you’re gonna want to try and dial that aspect down for the beer. Some is good. A lot is bad. If you get too tannic, it’s not the end of the world. Good news is that it’s a compound that can fade over time, similar to the green apple flavors you can get if there’s acetaldehyde in your beer. However, if you can avoid it, it’s best to not have it at all.
The next step in my process is boiling the wood, which does two things. First, it’s a step towards sanitizing the wood to kill any sort of critters or wild yeast in the oak that will fuck up your shit. Second, it also pulls a ton of tannins out of the wood, making it less potent. I’d say some shit about how it helps open up the pores of the wood, but that gets a bit defeated by the next step.
Pretty simply put, toss your cubes/staves into a pot of boiling hot water and let that shit rip along for about 15-20 minutes. That’s it. What’s crazy is how fast your water changes color. Within seconds, it’s gonna go from crystal clear to brown, to straight up the color of a dipper’s spit bottle. I’ve not tried, but I assume if you reduced that down further, you could essentially make your own liquid smoke.
Step 4. Kilning and Toasting
So, after the nice little jacuzzi bath, your wood is pretty much sterile, but also soaking wet, which isn’t exactly conducive to absorbing those nice flavors of whatever you’re aging them in.
Kilning after boiling is another nice two-fer step. Not only are you drying out the wood (and continuing to further sterilize it at a high heat), you also get to affect the flavor control to your exact liking again. Remember that graph that looked like a janky Excel chart a few steps up? This is where that comes back into play.
Now, a majority of this is going to be by eye, but the temperatures certainly help. The higher and longer you go, the darker your roast will be, the darker the flavors you get out of it, with the opposite being true for a lower temp.
For the majority of my purposes, I shoot for a medium toast. I set my oven for about 375°F/190°C and I’m going to start the timer for 15 minutes. From there, it’s a game of keeping an eye on your wood and getting it to the color you want. After about 20 minutes at 375°F, This is the medium-light toast I ended up with:
Still darker than the initial fresh cut oak than I started with, but not any amber tones or a dark chocolate color at all. Just a little kiss is what I wanted.
At this point, the wood is bone dry and, after two rounds of intense heat, completely sterile. That means that there’s only one step left in the process of making your own barrel-aged simulation program: picking your poison.
Step 5. Into the Drink It Goes
I’m including this for posterity’s sake, because let’s be honest, this is the easiest step in the whole process. Get yourself a nice, sealable container, like a mason jar or tupperware or something, drop in your wood, and then add your spirits. That’s really it.
It’s gonna take some time for your liquor to really infuse deeply into the wood, but afterwards, it’s as long as you want to age it. My recommendation is usually a week or two is plenty of time.
After that, it’s time to throw it into your brew. You’re going to want to taste test the batch of beer periodically, maybe every 3-4 days, just to make sure you don’t over oak it, but again, this all comes down to personal taste.
There’s also an extra shortcut that, as a homebrewer, is quite convenient – add in the extra juice that the wood was soaking in. As a warning, this is a way that you can very quickly overpower your brew, but it’s effective. I might suggest that, after you take your wood out and add it to the beer, save the extra super-oaked liquid off to the side and you can dose the beer with it to taste at bottling or kegging time. Logistically, it can be a bit more difficult on a professional level since, legally, you aren’t allowed to bolster your ABV with foreign alcohol sources, but on a large scale batch, 750 mL of wine in multiple barrels of beer isn’t going to really affect your ABV. Just don’t dump into like a case of Jack Daniels and you’re fine. For homebrewing purposes, I guess you could really just cut out this whole process and do that, but then you lose a lot of the extra oak character and, honestly, it’s a really shitty way that’s kinda cheating. And you’re gonna fuck up your ABV on such a small level.
Bonus Step: A Non-Drinker’s Guide to Booze
I also want to talk a little bit on the spirits side of things, as some people just don’t like drinking liquor or are unfamiliar with some more obscure shit.
Bourbon is far and away the most popular liquor/spirit that brewers and homebrewers alike use for wood aging. It’s vanilla, it’s cinnamon, it’s fucking gnarly. Beyond that, all those flavors marry perfectly into an imperial stout. Who doesn’t like that? Wine is the next most popular, and that goes great with sours and saisons. The tartness, the grape and fruity tones, and the lightness play nicely with others. But looking beyond, there’s a literal store of booze and wine to think about using. Unlike buying a barrel, which means that you’re stuck with whatever was in it, you now have free rein to put your freshly kilned oak chips into whatever fucking sauce your little heart desire.
The world is your oyster.
So, I’m just gonna list out some other potential candidates for aging your oak in, aside from the usual suspects. My main suggestion for selecting your spirit – Look towards cocktails and mixology. While a more recent trend of making beers that mimic or recreate some cocktails’ flavors, it’s interesting to see how just individual liquors and spirits can complement a good beer. Look towards cocktail recipes and bartender friends for some ideas. It’s best to understand what flavors your beer/s has and then complementing and playing to those strengths.
- Rum – There’s more to rum than the caramel-colored, over spiced junk like [insert naval title & male name]. For example, Zaya is a dark rum that almost tastes like a sweeter bourbon. You can also get nice quality white rum that will impart lighter tones, like floral or even some banana notes with a light sweetness.
- Tequila – It’s becoming more popular, especially since goses are cool and you can just throw some limes in that bitch and BAM! margarita gose. But tequila itself loans a nice variety of flavors depending on what aging you go with. Blanco (aka silver, unaged) can give you some sweet tones with notes of black pepper, pumpkin & lime tea. Reposado (2-12 months in a barrel) offers some more complex notes with hints of oak, vanilla, ginger & caramel. Añejo (aka gold, aged ~14 months) comes at you with hints of wood, nut, raisins & grapefruit.
- Mezcal – Similar to tequila, they’re pretty much cousins, as they’re both made from agave, but the catch is that mezcal is made with cooked agave piñas. The cooking process causes a chemical reaction that ends up giving mescal a flavor of a slightly smoother and smokey tequila.
- Akvavit – Traditionally Scandinavian, akvavit gets its distinctive flavour from spices and herbs, typically cardamom, cumin, anise, fennel, dill, and lemon or orange peel. Think of it as an herbal schnapps for vikings. A unique apertif, Haand Bryggeriet, a Norwegian brewery, did a version of their Dark Force imperial stout in akvavit barrels and it was killer.
- Gin – Gin is a somewhat trickier spirit. It’s very light, delicate, and while it can be citrusy, it’s usually more herbal and botanical or spruce-y. However, this can loan itself well towards light sours and fruited beers with citrus. However, lots of gins taste different, so it’ll be to your tastes
- Amaro – Amaros, similar to gin, are botanical-infused liquors, and are very much an aperitif, typically consumed post-meal to aid in digestion. Italian in origin, there are as many amaros as there are herbs and spices. Also worth noting that it’s pretty fucking easy to even make your own. Fernet is probably the most common example.
- Amaretto – Another Italian liquor, amarettos are traditionally made with the noyeaux from apricot pits (the white meat inside) and has a distinctly almond flavor. Goes well with imperial stouts.
- Fruit Liquors – Now, I’m not gonna say that 99 Bananas is a great choice, but do you. Specific thoughts in this category would be more along the lines of Grand Marnier and Cointreau. Think light accents to the beer, rather than having the liquor being a flavor on the forefront of the beer. This is going to be like the bass in your favorite song – it’ll marry the rhythm section of the drums into the vocal and guitars, seamlessly supporting from the back.
- Sake – Calling sake a “rice wine” is a little misleading, as it’s actually a little closer to being beer, but sake itself has a very light, distinct quality. Depending on the yeast strain used, it can actually have a lightly fruity tone to it. Hitachino Nest (Kuichi) specifically ages the XH beer in sake barrels.
Fuck around. Have fun. I mean, I’m from Pennsylvania, so I don’t know if I’d do a boilo-inspired stout for the winter, but, carpe diem – seize the carp. Experiment and see what works for you. There’s literally nothing stopping your from living your dreams on this one.
Alternative title to this, by the way: To Each His Oak.