What Is The Right Amount of Oak Cubes?

One of my favorite styles of beer is an Imperial Stout. Not just any Imperial Stout, but one that has been aged in Bourbon Oak Barrels. It really doesn’t get any better than that, especially if it’s done right.

As a homebrewer, procuring a used 50+ gallon oak barrel to condition my homebrew doesn’t make a lot of sense. Luckily, we homebrewers have plenty of options, one of them being oak cubes.

The question is, what is the right amount of oak cubes to use if you want to impart a subtle oak/bourbon character in that Porter or Stout you just brewed?

We are about to find out. I just brewed my first Stout (not a RIS), but I was going for that oak/bourbon character. I needed to start somewhere, so it’s a good as a time as any to start experimenting.

Chocolate Bourbon Stout (CBS)

Not wanting to go too crazy with my first Stout, I elected to find a decent recipe that I could build on. I went with the Rogue Chocolate Stout clone, with a few minor tweaks.

While the grain bill and hop charges remained in-line with the clone recipe, I opted to go with cocoa nibs in the secondary instead of the chocolate extract. In addition, it needed to have the oak/bourbon character I love.

The problem was, how much oak cubes is the right amount? Oh, and one other variable that I needed to take into account, I didn’t have months and months to condition this beer. I would be brewing this in mid-October, and I wanted it ready in time for the holidays.

That would give me about 6 weeks or so to condition this Chocolate Bourbon Stout.

How Much Oak Cubes Should I Use?

After doing a whole lot of research, trying to figure how how much oak cubes to use, I discovered opinions were all over the board.

It seems that the consensus is that oak cubes impart their flavor over the long haul. It wasn’t uncommon to see homebrewers conditioning their beer for 6+ months on oak cubes.

I ended up purchasing my oak cubes from MoreBeer, and in the description of the product it stated:

Oak cubes also release their flavor into your beer more slowly than chips, giving you more control over the final degree of impact in your beer. You should plan on an extended aging period of 1-6 months when using cubes. This longer contact time again promotes flavor complexity by allowing all the flavors of the oak and your beer to marry.

Recommended Dosage is 2 oz per 5 gallons for impact equivalent to aging in a brand new oak barrel.

MoreBeer

Given I wouldn’t be doing an extended aging, and some of the other information I gleaned from my research, I decided to go with 2 oz. of oak cubes for my 3.5 gallon batch. These oak cubes would stay on the beer in my secondary fermenter for 6 weeks.

Oak Cube Preparation

Now I wasn’t expecting to just dump 2 oz. of oak cubes in my secondary fermenter, I needed a way to prepare this oak.

I followed some oak preparation guidelines I found for a Dragon’s Milk clone. While they were using oak chips, I used the same preparation for my oak cubes.

1. Boil the oak cubes in water for 5 minutes to extract any tannins. Dump the water and place the cubes in a suitable container that can be sealed. I used a quart canning jar.
2. Soak the oak cubes in a cheap Bourbon or Whiskey for 5 days. The amount doesn’t matter and you’ll be dumping that Bourbon/Whiskey after the 5 days.
3. Soak the oak cubes in a decent quality Bourbon for 2 – 3 days.

At the end of the last soak, you’ll dump the entire contents of the jar into your secondary fermenter.

Which leads us to our second problem. How much Bourbon do you use to soak the oak cubes?

This was going to require some experimentation. Based upon some quick math, I decided to go with 8 oz of Bourbon for my 3.5 gallon batch. Keeping in mind, I would have about 3 gallons of beer that I was racking to my keg that I was using as a secondary fermenter. That should have equated to .25 oz of Bourbon for a 12 oz pour. Seemed like a reasonable number at the time.

The Tasting

What is the right amount of oak cubes to use in a beer where you are looking for a subtle oak flavor? What about the Bourbon? How much is too much?

I was pretty excited to try this beer, especially after I let it sit in my secondary for 6 weeks. I’ve never waited this long to try one of my beers.

That first taste left me somewhat disappointed. The aroma was the first that gave things away, as it had a very heavy Bourbon smell. The taste confirmed my fears, as the Bourbon was overpowering, and covered any of the other flavors I was hoping to get from this beer.

What about the oak? I couldn’t really taste it. I don’t know if it was the Bourbon that was covering up any oak, or if 6 weeks wasn’t nearly enough time.

I was a little disappointed with this recipe. I felt it missed the mark on what I was aiming for in a Stout. Could have been due to the heavy Bourbon taste, but I felt it was lacking the roast and chocolate character I expect in a Stout.

What about next time? I wouldn’t hesitate letting a beer sit on oak cubes for an extended period of time. If I’m going with an Imperial Stout, 4 – 6 months would be ideal.

What about the Bourbon? I would cut the amount I added to the secondary in half. For a 3 gallon batch in my secondary, I would limit this addition to 4 oz. Less is more, at least for me.

Cheers…