RD1 Amburana Bourbon: How Brazilian Wood Changes a Kentucky Whiskey

RD1’s green-label Amburana expression begins as Kentucky straight bourbon. Its defining step comes later, when Brazilian Amburana wood staves are placed inside the barrel. That distinction matters: this is neither bourbon made in Brazil nor a whiskey aged in an Amburana barrel.

The wood gives the release an identity that independent reviewers describe in strikingly different ways. Cinnamon is a recurring reference, but whether it complements the underlying bourbon or crowds it out is a matter of interpretation.

At a glance

Full name: RD1 Kentucky Straight Bourbon Whiskey Finished With Brazilian Amburana Wood.
Bottling strength: 110 proof, or 55% alcohol by volume.
Base whiskey: aged at least four years before the Amburana finishing step, according to RD1.
Method: Amburana staves are inserted into the bourbon barrel; the disclosed process does not call for a second, all-Amburana barrel.
Finishing duration: not specified in RD1’s published description.

The Kentucky whiskey behind the name

RD1 announced this expression in April 2023 as part of an expansion of its wood-finished bourbon range. Its 110-proof strength separates it from the French-oak and oak-and-maple expressions named in that announcement. Proof identifies the bottling strength, though it says nothing by itself about how a whiskey will taste.

The company takes its name from Lexington’s historic Registered Distillery One, associated with the Ashland Distillery established in 1865. That history is the brand’s inspiration, not the origin of whiskey made in the nineteenth century. RD1 was founded in 2020, and the distinction between the historic distillery and the present-day producer is worth keeping clear.

Lexington is also where RD1 opened its visitor and research-and-development distillery in 2025. In its opening announcement, the company said its Kentucky straight bourbon continued to be produced at Western Kentucky Distilling in Beaver Dam, while the Lexington site focused on visitor experiences and finishing experiments. A Lexington address, then, should not be mistaken for a claim that this bourbon was distilled there.

What the Amburana finish involves

Amburana has a longer association with Brazilian spirits than with Kentucky bourbon; it is among the woods used for cachaça maturation. RD1 applies it differently. According to the producer’s description, its partner cooperage drills small holes in Amburana staves in a honeycomb pattern, and RD1 inserts those staves into barrels holding bourbon that has already aged for at least four years.

Drilling exposes more wood surface to the liquid, which helps explain why the stave preparation is central to RD1’s account of the process. The company does not publish a precise finishing time on its product page. Without that detail, it would be misleading to describe the whiskey as having spent a particular number of days or months in contact with Amburana—or to assume every wood-finished bourbon receives the same treatment.

“Brazilian-spiced” can be a useful shorthand for the aromas people report, but it can also suggest the wrong production method. RD1 describes a wood finish, not an addition of cinnamon, nutmeg or other baking spices. The distinction is between a spice-like impression in a finished spirit and a documented list of added spices.

How to read the bottle

The words “Kentucky straight bourbon whiskey” describe the base spirit; “finished with Brazilian Amburana wood” tells you what happened afterward. The Alcohol and Tobacco Tax and Trade Bureau’s labeling examples distinguish straight bourbon from bourbon-based products that undergo a further finish. Reading the entire designation is more informative than treating “straight bourbon” or “Amburana” alone as the whole story.

RD1’s statement that the bourbon aged four years or more refers to the bourbon before the staves were introduced. It does not establish how long the finishing stage lasted. Nor should the 110 proof be read as a sign of unusually long maturation: age, strength and the type of wood used for finishing answer different questions.

There is a practical difference between staves inside an existing barrel and transferring whiskey into a barrel built from Amburana. Both bring spirit into contact with the wood, but they are not identical methods. RD1’s published account specifies staves, making that the accurate description for this expression.

Where the flavor accounts diverge

RD1’s own tasting notes mention apple cinnamon, nutmeg and light brown sugar on the nose, followed by spice cake and ginger snaps. Those are producer-provided descriptions, not independently established flavors or a guarantee of what any reader will perceive. They do, however, make the intended spice-forward character plain.

Independent accounts agree that cinnamon is prominent but differ on its effect. Breaking Bourbon found the finish integrated with caramel and oak notes from the underlying whiskey. Its review disclosed that the publication received a complimentary sample. Those observations are the reviewer’s, not a tasting conducted by Drink More Bourbon.

Bourbon Lens described an initially near-overwhelming cinnamon sweetness, with apple and baked-fruit notes emerging later, and found the finish thinner than expected. That is a meaningful difference from calling the wood seamlessly integrated. Together, the accounts show why a list of dessert-like descriptors is less useful than asking how much of the original bourbon remains perceptible alongside them.

What can be established is the whiskey’s stated strength, its bourbon base and RD1’s disclosed stave-finishing method. Its balance cannot be settled by those specifications, the brand’s tasting notes or an award. For this expression, the most useful question is also the most subjective one: how much cinnamon-led Amburana character belongs in the glass before it begins to obscure the bourbon beneath it?