Andrew Wiehebrink, director of spirit research and innovation at Independent Stave Company (ISCO), shares his expertise and experience concerning creating flavor profiles, how different factors change the flavor of whiskey, and the best way to drink bourbon.

AF: How does the process of creating a flavor profile with a customer begin?

AW: It usually starts with a visit to our Kentucky Research Center to discuss the goals for the new product. From there, it can go a few different ways. Most of the time customers have a very specific flavor profile in mind and they say, ‘We don’t want to deviate from this. You need to design a maturation program around that.’ We take as many factors as we can into consideration and then get to work. Other times they don’t have any specific goals in mind, but they want to try something new. If that is the case, we pull samples from our library and start tasting. They always find a handful of things they like and from there, they put some barrels into trial using their distillate and await the results. Depending on the outcome of the initial trial, we can circle back and tweak certain parameters to get as close as possible to what the customer wants.

AF: What’s an example of what a customer might say they’re looking for?

AW: A good example might be they want to design a very balanced whiskey that appeals to the casual drinker and doesn’t have really strong aromatic characteristics. On the other hand, it could be something along the lines of, ‘We want this whiskey to have notes of vanilla, hints of spice and finish with a strong smoky note.’ It varies between extremely general descriptions on the overall profile to very specific flavor and aroma characteristics. Sometimes we can accomplish the goals with one type of barrel and other times it might take four or five barrels to deliver a certain profile.

AF: What is it like working at ISCO to create flavor profiles for customers?

AW: It is extremely technical and very specific. We utilize a lot of different resources to try and meet the customer goals as best we can. We have a lab in Napa, California, that is equipped with our analytical chemistry equipment, and we have our new research center in Kentucky, where we perform a lot of flavor discovery trials and conduct all of the sensory analysis. Between the two facilities and a very skilled R&D team, we pretty much have every kind of tool available to bring the best flavors out of the oak. It’s always interesting and we always learn something new.

AF: What part does your division play more specifically in the process of developing the profiles?

AW: The spirits research division is normally where all the brainstorming begins and the initial flavor discovery trials are conducted. That is where we’ll have some initial talks about what it is the customer is trying to achieve. We’ll sit them down, we’ll say ‘Okay, what category does this fall under? Is it a bourbon, is it a single malt, is it a rye?’ We want to get as much information as we can up front. We ask if they have any distillate or maturate we can taste or if they have any kind of flavor goals in mind. At some points it can get very complex. Once we conduct our trials in the lab, one of our cooperages will produce the products and ship them to the customer.

AF: How do you help customers develop a flavor profile when they have a general idea of what they want but don’t have specifics?

AW: We have a big whiskey library at our Research Center which is stocked with spirits from all of our different barrel experiments. If our customers aren’t sure what they are after, we invite them to walk through the library and just geek out. If they have a question like, ‘What happens when we use French Oak or what flavors does this toast profile produce?’, they can go back in the library, pull out relevant studies and taste through them. We can tell them all the analytical stuff, we can tell them what to expect from different barrels, but when they get the chance to actually taste it for themselves, that’s when it really hits home.

AF: Do you get requests for flavor profiles that can’t be done?

AW: We get a lot of different requests to produce unusual flavors. Sometimes we have to tell the clients, ‘Listen, with oak there’s a lot of flavor possibilities, but some of this stuff just isn’t possible or it is out of our control. You can’t get these flavors from lignin; you can’t get them from the hemicellulose.’ Sometimes we have to tell customers that we’ll give it our best shot, but it’s going to be a bit of a guess for us as well. Other times, we simply have to tell them they should probably pursue something a little different.

AF: What are some of the characteristics American oak can add to a flavor profile?

AW: The best analogy that I can probably give, as far as overall flavor profile, is this: American oak is that loudmouth at the party. He always stands out. He’s easy to spot. That’s kind of indicative of the flavors for American oak. They’re really bold; they’re really easy to distinguish. You don’t have to do much digging. If we were to compare that to French oak, for example, he’s that quiet guy in the corner. He doesn’t really say much, but when you start to talk to him, start to get to know him a little bit, he’s got a lot to say. And that’s indicative of French oak, because with French oak, the flavors aren’t as pronounced, but it produces a flavor profile that is very nuanced. It produces a lot of different flavors. The general rule of thumb is that American oak is typically sweeter and French oak tends to be a little spicier. But how you treat the wood has a lot to do with what flavors will be lent to the whiskey.

AF: How do the different flavors translate to a physical difference in the wood?

AW: Through different variations in growth rate and different concentrations of certain constituents. Tannin, for example, can lend some woody characteristics and changes the mouthfeel of the spirit. French oak has more tannin than American oak, and that difference will have considerable effects on the final outcome of the product if the aging is long enough. American oak has more lactones of which there exists two different isomers: there’s a cis isomer and a trans isomer, and the ratio at which those occur is very important. It just so happens that American oak has a more favorable ratio of those two isomers, and basically what that translates into is a greater perception of sweetness or coconut-like flavors in the product. The rate at which a tree grows influences the overall porosity of the wood. This is important when it comes time for oxygen to make its way into the whiskey. Oxygenation has a huge effect on the flavor profile of barrel-aged spirits, and the porosity of the wood alters that process.

AF: The oak itself and its variations, how do you manage that part of the process?     

AW: Well, of course, you’re dealing with a natural product. So, no matter how hard you try to reduce the variation in the barrels, no two barrels are going to be exact. Trees grow differently from one another. They have different physiological characteristics and the constituents can vary within the same tree. We have a lot of proprietary technology in our process that ensures we can repeatedly make a specialized barrel over and over again with high accuracy. For example, we have machines that can look at the grain of each stave and then sort accordingly. That gives us the ability to construct a barrel using staves that experienced the same growth patterns.

AF: What kind of effects do heat treatments have on the flavor of the final product?

AW: The effects are huge, and in my opinion, it is responsible for the majority of flavor lent by the barrel. When oak constituents start to break down, or in other words, when you begin to apply heat to a barrel, a wide variety of compounds will begin to form. And those compounds will appear according to certain temperatures that are being applied to the wood. So, if you apply a little bit of heat you get one compound, if you apply some more you get another one. Each one of those compounds will lend certain flavor or aroma characteristics to the whiskey. Any kind of heat treatment applied to the barrel makes a big difference in the final product and it’s something we watch very closely.

AF: What’s the most enjoyable part of coming up with new barrel experiments for you?

AW: I’m kind of a tinkerer by nature, and I’m a very curious person. Whiskey maturation is so complex, and nobody really has it all figured out yet. With our experiments we are uncovering new territory every single day, and that’s pretty cool. We do experiments to further our understanding of maturation and to develop new products for our customers. Feeling like you’re making a difference in an industry that spreads across the globe, that’s the fun part.

AF: How do you drink your bourbon?

AW: Usually, I drink my bourbon neat, and I will have two or three bourbons poured at one time. I think one of the best things you can do to start learning how to pick out the different flavors is to do side by side comparisons. That’s something that my dad taught me a long time ago, and it’s always stuck with me. As far as my favorite bourbon — if you ask me on one day, I’ll tell you one thing, and if you ask me the very next day, I’ll tell you something completely different. It just depends on the mood.

Behind the Scenes: Barrel-Making

See what comes before the barrel at Independent Stave Company, Bogle Vineyards and Michter’s Distillery!