Terroir in Bourbon: The Next Big Thing

 Terroir in Bourbon: The Next Big Thing

Terroir is a word that I’m starting to hear trickle into the whiskey category more often, but is still relatively unknown from what I gather from conversations. This is a French word typically used in the wine world which describes the collection of elements that contribute to the wine’s “sense of place.” The factors would be environmental impacts like soil, sunlight, rainfall, etc., and the wine production methods. If you look at all the factors, the list can get pretty long. But we’re going to look at some of the factors that contribute to the flavor of Bourbon/American Whiskey and why I think that not only is it on the rise, but might be the next big thing in the bourbon world. 

First, let’s look at some of the categories within bourbon that contribute to flavor. One, you have the grain, and what is done with the grain after it’s harvested. Two, you have the grain recipe, fermentation, and distillation of that grain. Three, you have the wood and coopering (barrel making) process. Last, you have the maturation of that spirit in barrels made from that wood, along with the post maturation blending, proofing, and filtering. Don’t get weary yet, but there is a lot of different factors that impact what we taste in the final product. Although I could add more details, I hope that this article brings some simplification of a highly complicated, large-scale operation that goes into getting a great bottle of whiskey.

Starting with grain, imagine a time where you’ve been around a farm or field with crops growing. Think about the weather. Was it hot? Cold? Rainy? Could you smell manure in the air after the farm had been fertilized? Could you hear the stalks of grain, or corn in the wind? I opted for visual imagination to make you think about the many factors that go into the farm decisions of how they grow their grown. They have to decide how they want to manage their farms with fertilization, tilling or not tilling, figuring out irrigation if rain is too much or not enough. I have to admit, I’m not a farm boy, but reading about the many decisions and hearing about it from people I know who put in the hard work on their farm is fascinating. There are an exhausting amount of decisions to be made. All of these human factors and environmental factors effect how the grain will grow. Some grain grows better in warmer climates, some is better in cooler, and some can grow in just about any conditions. In order to not get too off-topic, let’s simplify and skip to the end of the grain processing. Now the farmers decide if they have grown multiple types of corn, for example (blue corn and yellow corn), do they separate the corn varieties individually, or blend them all together before selling them? Well that can also depend on the preferences of whoever wants to buy the corn. 

Fast forward to the distilleries. Depending on what type of whiskey they want to make, they will buy certain types of corn, rye, wheat, malted barley, etc… Once the distilleries figure out what their grain recipe will be for their bourbon, then they have to decide on what decisions they have to make for how they mill their grain, ferment it, and for how long, and then how they want to distill it. From what I’ve read from various books and heard from distillers on podcasts, each grain needs different temperatures in order to extract the right amount of flavor, proteins, and starches. You can actually extract too little or too much, so there is a lot of thought and experimentation put in at this level. Also, the law requirement for bourbon is that it cannot be distilled above 160 proof in order to preserve flavor. If distilled any higher, than you are stripping too much flavor and the process becomes very similar to vodka, which is not completely flavorless, but generally considered flavorless. It seems that the distillation step coincides quite a bit with each distillers philosophy on how they want the flavor of the distilled liquid to interact with the barrels that it is stored in. 

The law also requires that no matter what the distillation proof is, the liquid must go into the barrel no higher than 125 proof. If the product is distilled to 160, then then water must be added to bring it back down to 125, which can be a good thing because when we talk about the barrels that the liquid goes into, the wood sugars are more soluble in water versus alcohol. If you go the other direction, and distill to a lower proof like 115, you can put it in the barrel and add no water, which some might argue is preserving more of the flavor of the grain. There may not be any ‘right’ or ‘wrong’ way to do things, because it really comes down the distillers vision for what flavor they want to bring out in their spirit. And a large contributor to the flavor comes from the oak barrel.

The impact of the barrel is clearly evident as the distilled liquid goes into it completely clear, and comes out the different shades of brown that we attribute to “bourbon”. This happens from the interaction over time from the liquid going further into the wood when it is hot outside, and pulling out of the wood when it is cooler outside. Before we get to the color of the end product, lets first talk about where the wood comes from and how the barrels are made, which again, affects so much of how bourbon tastes. Some argue the largest part of a bourbon’s flavor comes from the barrel. Another stipulation of the law for Bourbon is that the whiskey must be put into brand new charred oak containers. It doesn’t actually specify oak type or if it must be put in a barrel. You could actually put it into a charred oak bucket, and call it bourbon, which is something I’ve always found quirky, and interesting. Since barrels are the industry standard, that’s where we will keep our focus. 

The wood comes from a few different places. Different species of oak grow all over the world, and some are better for bourbon. The industry norm is American white oak because of abundance, taste profile, and the porosity. It is porous enough that the barrel can allow small amounts of air in and out, as well as whiskey in and out of the wood, but not so porous that the whiskey leaks out.  Some other species of oak are more prone to leaking. A lot of American white oak comes from the Ozarks in Missouri, but it is not the only place. Now how this relates to terroir, if majority of this American white oak comes from the same place, the expectation might be that it should all taste the same, and for the most part that is correct. Generally, it yields similar flavors if it’s from the same place, but with everything else, there are outliers. But for now, let’s assume that all oak from the same region yields similar results in flavor. As you can imagine, if you buy oak from different places, and make barrels from them, the wood would most definitely impart different flavor depending on the species, growing conditions and so on. (As you can see, wood is yet another topic we can keep diving deeper into specific variables to further discuss how they affect flavor, but we will stop here for simplicity.)

If we stick to the standard American white oak, how the wood is processed and made into barrels is yet another thing that will impact the bourbon’s flavor. Cutting the logs into staves, which are the individual pieces that are connected together to construct the barrel is a difficult and labor intensive task. After this process the staves are sent to the cooperages, who are the makers of these barrels. But before the barrel gets made, there is a process called stave seasoning that is a necessary process. The process of seasoning means that these pieces of wood are cut into staves and then stacked and left outside for anywhere from three months to 48 months. Usually a common standard I hear in the industry is 12-24 months. Like any industry the longer you wait, the higher the cost, but the benefit of waiting longer is the seasoning process lets the wood’s tannins and green oak flavors break down over time in the elements. If you didn’t season the staves before making them into barrels, your bourbon might start to taste and smell like the lumber section at a hardware store, and not many people would want to drink that. Seasoning essentially lets out those fresh, harsh flavors, and makes the softer more smooth flavors the wood has to offer, more accessible when the liquid goes into the barrel.

After the seasoning process, the staves can now be made into barrels by the coopers. Aside from barrel assembly, the next variable that affects flavor is toasting and charring the wood. In the wine industry it is common to toast barrels. This toasting process makes the wood sugars more available on the inside surface of the barrel, and can impact the flavor of whatever liquid you put in it. Toasting is the softer approach. The inside of the barrel is exposed to an indirect heat source at a lower temperature for a longer period of time, sometimes up to one hour. In the case of charring, it is a hotter, open flame heat source for a very short amount of time, around 30-45 seconds, and both have big impacts on flavor. The toasting process brings out chemical compounds in the woods that contribute those vanilla, caramel, and spice flavors that we love. The charring process also acts as a method of filtration for the spirit as it moves in and out of the wood. Each distillery talks about each of these options and how they want them to impact the final product. These choices each have different affects on how the whiskey interacts with the wood, and extracts flavor. 

The long or short process after the distilled whiskey goes into the barrel is called maturation, and there are many factors here as well, that can affect the flavor. There are different types of storage warehouses and methods of storing barrels, and each one again has a different affect on the maturation process. One thing that whiskey does, and is the genius of the porosity of the oak barrel is moving in and out of the oak. When the barrels are hot, the whiskey expands because of pressure and goes further into the wood, and when it gets cold, the whiskey contracts and all that whiskey that soaked into the oak, comes back to the center of the barrel. This movement is how the maturation progresses. This can happen at different rates depending on the many differences is weather. If you have a tall warehouse, the top floor might be much hotter than the bottom floor in the summer. If it’s hot all the time, the liquid tends to interact with the oak more, and if it’s cold, the oak interaction is less. If it is hotter in the warehouse, more water tends to evaporate from the liquid and the proof will go up, but if it’s cooler, less water escapes and water tends to be taken into the barrel from cool temperatures and humidity, and the proof will go down. These different aging environments will have large impacts on the color and flavor of the spirit at the end.

Up to this point, focusing specifically on any one of the factors above, and any difference has large effects on how the bourbon will taste, but the distillery ultimately decides how they want to present the final product. Blending, proofing, and filtration all have major effects as well. Let’s say that you have some barrels that taste like cherry, vanilla, and oak. Then some other barrels that taste like apricot, cinnamon, and pie crust. The distillery can decide whether to blend all of these together and potentially present all of these flavors integrated together, or blend them separately where there are two separate products that taste totally different all from the same distillery. Sometimes when bourbons are blended together, they don’t taste like you might expect, and other times they do. In some cases, after the blend is made, the flavors need some time to sit together and ‘mingle’ before they taste cohesive together. The blending process really is an art. After those decisions are made, do they want to showcase a high proof bourbon, or add water to it and make it appealing to more people? Generally, lower proofs are more appealing to people around 80-90 proof. Others prefer higher proof bourbon. They feel that the bourbon is in it’s truest form at whatever proof it comes out of the barrel (sometimes around 120-130+ proof), with more intense flavor. It’s all preference. 

If a distillery wants to showcase a bourbon “straight from the barrel”, generally that designates less filtration or no filtration (even though there will always be some filtering through a screen to catch bits of barrel char floating in the whiskey). This is appealing to many bourbon lovers because it delivers the experience of being at the distillery and trying the bourbon pulled from the barrel before anything can be done to it. A more ‘authentic’ experience per se. And when it comes to filtration, the bourbon may have bits of char from the wood floating in it, which most people would prefer to be filtered out. There are also oils and fats present in the liquid from the grains and distillation process which showcase texture. But in some cases, if the liquid is lower proof (80-90 proof), if it ever gets cold the oils and fats can start to clump together and look cloudy. This sounds gross and unappealing, but they are not harmful, but to make sure your product looks great and consistent in the bottle, a distillery can decide to chill-filter their bourbon, which removes those larger oil and fat molecules. This is debatable in some cases on whether or not this hurts flavor. Some of the best and biggest distilleries in the world choose to do this, and they have incredible bourbon. Some choose not to, and they also make incredible bourbon. One factor that is usually not debated for what chill-filtration impacts is mouthfeel of the bourbon. An oily mouthfeel is a desirable quality. If the chill-filtration takes place, it doesn’t mean the bourbon won’t have an oily mouthfeel, but certainly some of the contributing factors for it being better may be taken away. 

At this point, the possibilities of variables affecting flavor may seem endless, and that is overwhelming, and fascinating at the same time. And now that I’ve provided an unnecessary amount of context haha, let’s get into the topic of Terroir being the next big trend in bourbon.

Although not every single detail was discussed, I think they provide enough ideas to show what can be highlighted in the next wave of bourbon releases. There have been a few bourbon distilleries who have released bourbons with terroir in mind, but nothing to the extend of an Irish Whiskey distillery called Waterford. They specifically tried to capture the terroir of grain from different farms all over Ireland. They processed the grain separately, and distilled it separately so you could see how these micro-climates affected the end product. To my knowledge, there has not been an American distillery who has gone to quite the extent that they have, but there have been some movement towards similar ideas recently. 

A release I think of are Wild Turkey’s Single Rickhouse releases. We do not know if any other variables are controlled, but the whole point is to showcase how different rickhouses affect the aging of different bourbons. Jim Beam also did this same experiment with the Hardin’s Creek. They released three 17 year old bourbons from 3 different warehouses, again, to showcase how different aging environments affects the differences in the final product. Another move in this direction is Maker’s Mark releasing the Star Hill Farms Whisky. This is a wheat whiskey with all of the wheat grain coming from their own farm, so technically, even though they grow Soft Red Winter Wheat, which is fairly common, it is grown and processed on their farm, and only they have access to the particular way they grow the grain, making their product unique from others. It is proprietary, as they say in the industry. This is not necessarily marketed as ‘Terroir’, but it certainly is an example. Another great example is Four Roses. They specifically market how different yeast strains paired with different mashbills can create different flavor combinations from their whiskeys, and you can definitely taste the difference. 

Craft distilleries have been more on the forefront of releasing whiskeys with different grains to showcase how different grains affect flavor. For example, instead of standard cereal rye grain, they might use Danko rye, or Rosen rye to distinguish a different flavor coming from their whiskey. This is arguably a better example of terroir since it is isolating a very specific variable, and one that is not normally used. You may not know the specific grain type going into your favorite bourbon, but if the distiller is explicitly stating that it is a specific type of grain, and you like the product, you may like expressions from other distilleries with that same grain as well. The more specific information you know, the better decisions you can make as a consumer, and more you can do to diversify what types of products you try.

Imagine one of your favorite distilleries releasing three different bourbons all with the same exact ratio of each grain (mashbill), but with three different corn varieties. Tasting them side by side would be extremely interesting. This is what a lot of wine showcases: different grape varietals blended at different ratios or as single variety expressions. Single variety expressions are the best way to really see how the grain tastes and what makes it unique from others. There are tons of different variables in wine, and I see this is one of the ways that bourbon/American whiskey expands as a category. A potential problem it creates is if one expression is more liked than others, maybe it makes less sense to continually make the less popular, and that is just business, I suppose. But, on the flipside, for educational purposes and having new ideas for new products, the possibilities are endless. It is also a direction that has not been explored often enough within bourbon/American whiskey. This experimentation also helps the category grow. Bourbon has been as successful as it has most likely because distilleries have found what works, and you know the saying, “if it ain’t broke, don’t fix it.” But this same sentiment is also what can keep some companies from expanding or keeping up with the market and potentially being left in the dust. 

I see this as the future of bourbon, or at least one of the successful lanes within the category. One of the reasons for thinking that is because bourbon consumers are smarter than ever. There is more information out there, and more research being done when it comes to making purchases than ever. People are starting to figure out what they like and what they don’t like. At the heart of a lot of bourbon nerds is a desire to try new things and see what interesting flavors different distilleries can produce with their bourbons. That type of consumer wants to try many different and new things, especially from distilleries they already love. Another small thing that should go along with distilleries producing and highlighting the effects of terroir on bourbon is a need for smaller formatted bottles as more of a standard. 200 ml bottles specifically seem to be a great size for this. You can get smaller format bottles for a cheaper price to try more expressions and really hone in and figure out what you like. More expression types necessitate products to be more available to try, and that also gives more people the opportunity to try it. Plus in my experience, I am more prone to buy more small bottles to try more expressions than even one large bottle at a distillery if I’m not sure I will like it. With the smaller format, I’m more willing to purchase the small bottle to try more things, and if I really like one of them, I will most likely be back for a bigger bottle later. I think it encourages sales across the board. 

Terroir truly is a fascinating piece of the puzzle in why bourbon tastes the way it does, and more expressions should highlight the specific reasons as to why the whiskey tastes the way it does. This empowers enthusiasts and casual fans to discover something new about why bourbon is so special. Hopefully this article inspires you to go down some of the same paths I’ve gone in my whiskey journey and discover where flavor comes from. It is fascinating how different grains do this with different categories of whiskeys, and I think the next move for innovation is to showcase the variables that impact flavor.

Monday, June 9, 2025

Article by: Drew Martin