Craft Spirits Magazine’s (CSM) Kristiane Weeks-Rogers sat down with Calen Kirkland of The Barrel Mill to discuss how the Minnesota cooperage became the first in the United States to craft barrels from Mizunara oak: a rare, notoriously porous Japanese wood prized for its complex flavor and character. In this conversation, Kirkland shares the two‑year journey from experimental spirals to full‑scale barrels, the challenges of working with Mizunara, and what this milestone means for American craft innovation.
CSM: What first sparked Barrel Mill’s interest in Mizunara, and when did you realize it was time to pursue making these barrels yourselves?
Kirkland: Yeah, great question. So, you’re probably aware, our infusion spirals—we’re bringing in species from all over the world for that. I don’t recall which one it was, but one that was super exclusive, super expensive, only 100 bottles out, countrywide.
And so, I keep my eye out for stuff like that. And so it was like, “Oh, okay. Yeah. We need to explore this wood and see, number one, can we get it? And number two, let’s start playing around with it.”
So, we reached out through our panels and got in touch with a cooperage in Japan. At the very beginning, I mean, we were just getting little bitty, probably like, I would say, two-by-two scrap pieces.
We put it through our spiral process and were able to make a sample spiral of an inch-and-a-half by inch-and-a-half size, basically. And all of those start kind of the same way when we get a new wood.
In my office, we had a Barrel Mill bourbon made for us, probably years ago, by The Foundry in Iowa, and it’s a 15-month-old whiskey in our 15-gallon barrels. And so I typically use that as just my base for testing purposes because it’s consistent.
I know exactly the notes that come off of that to begin with, and we’ve got ample bottles laying around in the warehouse. So it’s not like I have to go out and source anything.
So we started trialing with that in Mason jars, basically. First trial is usually 325 milliliters in a Mason jar, drop a spiral and just watch it and taste regularly.
A lot of times in the office, we might have experiment taste Fridays where a few people come into the office, and we’re just taking a tiny, 25-milliliter kind of sip and just seeing where it goes.
And it became really evident that we had something special here. So we contacted the cooperage in Japan again and said, “Hey, how much of this can we get?”
It started out as, again, pieces that were probably two inches, but at this point we could get a ruler’s worth at a time. So two by 12 inches, let’s call it.
And that was perfect. We could then run barrel packs with it. Our barrel packs consist of an inch-and-a-half diameter by nine-inch-long spiral. There’s six of them joined together.
And we brought some in, and it went immediately.
There were a couple of our long-term customers that we knew would really be excited about this. And yeah, they bought it up quickly. It was at $250 a barrel pack, which is one of our most expensive barrel packs that we offer.
And so we started developing this relationship with our cooperage partner in Japan and getting it more regularly, again, at the small size.
And there we started getting reach-outs from new customers that saw the spirals that aren’t necessarily familiar with spirals, but they want to do barrel finishing. And they’re like, “Hey, is this feasible to make a barrel for you guys?”
And I’m like, “No, absolutely not.” You know, we’ve got these little chunks. I can’t make a barrel out of that. But it got us thinking: Could we press that into a head, maybe, and make a hybrid barrel of an American Oak with Mizunara heads on it?
So, again, we continued our relationship with the cooperage in Japan, and I don’t exactly know what happened over there, but they freed up some more wood for us.
So they said, “Yeah, actually, we’ve got stave-quality pieces that we can send you.”
And we said, “Great, we’ll take a container.” And so we brought it over. From my understanding, Mizunara, the English translation on that is the water oak. So it’s a super, super porous wood.
And so building a barrel out of it started out very, very challenging. We would build it the same specification as our American Oak barrels, and at the end of our cooperage line, every barrel we make is tested.
So, a 53-gallon barrel, we put about 25 gallons worth of water in there and then high-pressure air test it, and that will push out any potential problems, either through stave cracks or through the heading.
And this was like something we hadn’t seen. It was coming through the stave, like through the wood. Very, very porous, very leaky. And we developed a way to test the staves before we built barrels.
So now we’re grading staves. How confident are we that this stave will hold before we actually make the barrel, just to save ourselves the rebuild time on it?
And even at that level, it’s still a very, very porous wood to work with, but our guys are getting pretty darn good at it.
So everything that we give our stamp of approval on and send out the door, it’s been leak-tested. We’re confident it’s going to hold, and it’s kind of the best that certainly we could offer.
CSM: Wow. How long did that entire process take?
Kirkland: Yeah. I would say from the first scrap piece to the first barrel out the door was probably all of 24 months, for sure.
I’m certainly biased, but I feel like we’ve got the best coopers in the industry working for us. I mean, our guys—pretty much everybody that’s back there on the production line—have been with us for 10 years-plus.
I mean, these guys are experienced. They’re great at what they do, and I feel like our barrels kind of showcase that. I would say the other thing that, you know, we had a plan where if we got it all over here and it was like, “Man, this ain’t possible,” we at least have the spirals to fall back on.
So we knew that we could convert the wood into spirals. It would be even probably more expensive than what our standard barrel packs were at that time, but we had a fallback plan at least.
And that’s actually what we’re using kind of the scrap wood for now—the staves that we say, “Hey, this is a C-grade stave. It’s just too porous. It’s not going to seal up.”
We turn that to spiral material anyway. So, you know, we at least had another product that we can pivot to, and we still do pivot to for the wood that’s deemed non-barrel-worthy. We still use it in spirals.
CSM: Were there any other unexpected challenges? I mean, I kind of feel like the wood itself is a pretty rough challenge.
Kirkland: It is. Yeah. I don’t know. I guess the other challenge—it’s a market challenge with it still, too.
Yes, these barrels are rare, and people want them, but there’s still that—I mean, it’s a very, very elevated price point for them. And in today’s whiskey market, that’s a tough pill to swallow for most distilleries.
I’ve talked to a lot of different distilleries specifically around Mizunara, and some of the biggest in the world might only have six to 12 barrels currently aging in their rickhouses because, yes, it’s super exclusive and tough to get, but the price tag on it, too, is really, really up there.
So it kind of feels like it’s a limited market of distillers that can squeeze that and justify that price tag. So there’s challenges around, you know, all the way around with it for sure.
CSM: And at the beginning, or towards the beginning of the conversation, you recognized that this is a special wood. What does that word mean to you? What makes it special?
Kirkland: So I’ll tell you the story where I really realized that we had something really, really cool. It was CBC time, so Craft Brewers Conference time, and we had just gotten back a little bitty sample that one of our customers had used.
So when we got those little samples, we did some testing in-house. We sent some out as well to a few of our customers that we knew would really enjoy it.
One of them sent us back something of his standard-based bourbon, the control of the experiment. And then the Mizunara-aged.
And I brought a little bit with me to a Craft Brewers Conference and—really, really well-respected. I probably shouldn’t name-drop him without running it past him, but super-respected brewer in the industry, very well-known for playing with our spirals and creating beers with different woods.
I gave him a sample on the CBC floor, and he looks at me and goes, “Wow.” That was the only words out of his mouth. It was just, “Wow. Wow.”
And then he went into detail about, “Holy cow, it just covers your palate and takes over,” all of these different notes coming out.
And that’s kind of what I was thinking back in Minnesota, in my office, but to get the verification from somebody as well-respected as him really was like, “Yeah, we’re going full bore with this.”
At that time, there were not many Mizunara releases out in the market. But we’re just like, you know, this is, number one, for the spiral side of things. We can bring the affordability finishing option to everyone.
Because even though it’s a high-end spiral, most places that want to work with Mizunara, they can justify that.
And then the barrel is for the customers that are more traditional on the finishing side of things. They don’t want to do an oak alternative finish. They want to do an in-the-barrel finish. Great. I’ve got an option for you on that.
CSM: How does the Mizunara compare with the traditional American oak in terms of tasting notes?
Kirkland: So it’s definitely more, I don’t know if oily is the word, but it coats your palate completely when done right. It really just kind of almost like an oily finish.
It covers your palate. With your traditional American oak, you get those classic bourbon flavors of vanilla, caramel, some smoky, some leather. You really kind of know what to expect.
With Mizunara, it’s almost like a sweet, spicy kind of thing. Much more spice, I would say, on Mizunara than your traditional American oak. A lot of sandalwood, a lot of floral.
I would say early on, I would have compared it to some cherry blossom, but then once we got the Sakura, that blows it out of the water on that sweet floral note.
But certainly some undertones of sweet floral, but very sandalwoody. I don’t know. It’s just really nice, and it’s really different.
CSM: Have you seen the demand evolve since you introduced your barrels?
Kirkland: Early on, like I said, just because of the exclusivity of it, it seemed like there was only one or two products on the market.
Today, I mean, not even really thinking about it, I can count about 15 or so just of our customers that have Mizunara-finished products on the market today.
CSM: Would you say that there’s particular categories of spirits where the Mizunara is showing the strongest interest?
Kirkland: I mean, I’m certainly bourbon and rye lead the way with it, but I’ve also seen some beers and, I don’t know, I know people have been playing around rum with it.
I don’t know if I’ve seen a rum or tequila yet, but I would expect that’ll be on the horizon.
CSM: How do you think that this Mizunara project fits into the Barrel Mill’s larger philosophy around innovation and supporting craft producers?
Kirkland: I mean, since day one that I’ve been here, we’ve always said that we want to be the wild wood guys.
So we want to bring those unique, one-off, really just wild experiences to our customers. And we’ve continued to evolve on that, too.
I think the Mizunara barrel—we’ve built an Amburana barrel or two in the past, but I think the Mizunara one was more than just a one-off. I think we’ve did about 80 of them now.
That’s going to evolve us as a cooperage and continue to challenge us and push the button.
We’re talking about potential French oak now, and what other woods can we potentially build a barrel with?
So there’s a handful of our cooperage competitors that are really kind of evolving in this innovation time right now to be creative and be different, and it’s been great.
I think we’re all challenging each other to be better. So it’s been good.
CSM: Would you say that working with the Mizunara was kind of like a launching point for you all to feel more confident to pursue more specialty woods, or was there something before that event?
Kirkland: No, I would say that’s really been a good precursor, I guess, of more innovation and the ability to not just build spirals with our exotic woods, but, hey, let’s—if there’s a demand out there and a customer wants to do this type of barrel, let’s do it.
Let’s not send them overseas for some sort of exotic barrel that they really have no clue where it’s coming from or what condition it’s going to be in when it gets here, not even factoring in the shipping cost as well.
So, I mean, when you factor all those things in, let’s keep that innovation here in the U.S. and really not only that, but stand—you know, we’re a company that’ll stand behind our product and work with you. I’m getting exactly what you want.
CSM: What are you most excited about for the Barrel Mill’s future?
Kirkland: I would say just kind of that what’s next. What’s going to be the next Mizunara wood, and not even necessarily on the French oak side of things.
Yeah, I’m excited to build some French oak barrels, but further down the road, you know, is it going to be a Japanese Sakura barrel?
We’re kind of in that infancy Mizunara stage with that wood right now, where we’re getting scraps that I can build a barrel pack with, but that’s really about it.
So, you know, will it be that or will it be something else? I think there’s a whole lot of runway still for building exotic barrels.