What is bottled in bond bourbon?
Updated November 2026 · BourbonTown Tours
Bottled in bond bourbon is bourbon that meets a federal standard first set in 1897: the product of one distillation season, by one distiller, at one distillery, aged at least four years in a federally bonded warehouse, and bottled at exactly 100 proof.
The phrase is a record of production, measured against federal rules. Reading it as a quality grade is a mistake.
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Quick facts
- The standard comes from the Bottled-in-Bond Act of 1897.
- Everything in the bottle was made by one distiller at one distillery.
- All of it came from one distillation season: January to June, or July to December.
- It aged at least four years in a federally bonded warehouse.
- It is bottled at exactly 100 proof, which is 50% alcohol by volume.
- Bond is a production standard, not a quality grade.
Bottled in bond requirements: bourbon's rules plus five more
Bond is built on the ordinary bourbon rules. Bourbon is made in the United States. Its mash is at least 51% corn. It comes off the still at 160 proof or less. It enters new charred oak at 125 proof or less. It reaches the bottle at 80 proof or more. Water is the only thing that may be added. Every bonded bottle clears all of that first.
The bond standard then stacks five more conditions on that base:
- One distillation season.
- One distiller.
- One distillery.
- Four years minimum in a bonded warehouse.
- Exactly 100 proof in the bottle.
Today these conditions are set out in federal labeling regulations enforced by the Alcohol and Tobacco Tax and Trade Bureau (TTB), at 27 CFR 5.88.
None of the five replaces anything on the base list. They narrow it. A bourbon bottled at 90 proof is still bourbon, and it is not bonded. A bourbon drawn from two distilleries fails the bond conditions. Same category, tighter rules, one phrase on the label saying the tighter rules were met.
What the 1897 Act was built to fix
The Act gave buyers a way to know who made the whiskey in front of them. Before it, a label told a buyer very little, because whiskey changed hands between the distiller and the shelf, and what arrived could be blended, cut or colored by someone the distiller had never met. The Act offered a trade: meet a fixed set of checkable conditions, and the bottle may say so. Colonel E.H. Taylor Jr. was among the Act's leading advocates.
The word bond points at the warehouse. Bonded premises are where spirits are stored before the tax on them is paid. Aging warehouses of that kind stand on the grounds of many of the distilleries in our Kentucky bourbon distillery directory. Four years in that warehouse is the aging floor bonded whiskey has to clear. Two years is the straight bourbon threshold.
What the bond label does not tell you
Bond settles a short list and leaves everything else open. The phrase does not cover:
- Quality. A bonded bourbon can be thin, hot or dull, because the standard measures process rather than the pour.
- Age past four years. Four is the floor, and an age statement is only required below four years, so a bonded bottle may carry none at all and still be well past four.
- The mash bill. Corn at 51% or more is fixed, and the rest can be rye, wheat or malted barley in any proportion.
- Barrel entry proof. The cap is 125 proof, and distillers work at different points under it.
- Where the barrels sat. Position in a warehouse changes how a whiskey matures, and the label is silent.
- Scarcity or price. Bond has no bearing on how much was made or what a shop charges.
Bond, straight bourbon and age statements
Bourbon has no minimum age at all. Straight bourbon has to sit at least two years. Bond doubles that figure and fixes the bottling strength too, so it is the strictest of the three.
Proof is the other difference. Bourbon and straight bourbon can be bottled anywhere from 80 proof upward. Bond removes that variable: one number, every bottle. Bottling proof also changes how many bottles one barrel of bourbon yields. For the two-year rule in full, read what straight bourbon means.
Bottled in bond is not a bourbon-only label
The bond conditions are not limited to bourbon; other spirits, rye whiskey among them, can be bottled in bond on the same terms. For how rye itself is defined, see how rye whiskey differs from bourbon. Heaven Hill, headquartered in Bardstown, bottles Rittenhouse Rye at 100 proof as a bonded whiskey and puts out Old Fitzgerald as a bonded bourbon; our Heaven Hill distillery guide covers the distillery behind both.
Bond does not change what kind of whiskey something is. It sits on top of whatever category the whiskey already belongs to. A bonded rye and a bonded bourbon differ in grain, not in the promise the label makes.
Frequently asked questions
Is bottled in bond bourbon better than other bourbon?
No, and the standard makes no claim that it is. Bond certifies where, when and how a whiskey was made, which rules out blending across distilleries or seasons and sets four years of age at 100 proof. Those are facts about production, not a verdict on flavor.
What does 100 proof mean on a bottled in bond label?
It means 50% alcohol by volume, since American proof is twice the percentage figure. For bonded whiskey the number is exact rather than a minimum, so 99 or 101 would fail the standard outright. Ordinary bourbon only has to reach 80 proof, which is why bonded bottles tend to taste more concentrated.
What is a distillation season?
A distillation season is one half of the calendar year: January through June, or July through December. Every drop in a bonded bottle must come from one of them. The rule stops a bottler mixing spirit made in different seasons and selling the result under one name. It is the part of the standard that guarantees consistency of origin.
Can bottled in bond whiskey be older than four years?
Yes. Four years is a minimum, and some bonded bottles carry age statements well above it. Others carry none at all, because a label only has to state an age when the whiskey is under four years old. If age is what you care about, read the age statement and treat the bond phrase separately.
How can you tell if a bourbon is bottled in bond?
Look for the words on the label: bottled in bond, bonded or a similar phrase. Proof alone does not tell you, because many bourbons are bottled at 100 proof without meeting the other conditions, and strength says nothing about the season, the distiller, the distillery or the four years in a bonded warehouse. If the wording is absent, read the bottle as ordinary bourbon.
Seeing a bonded warehouse for yourself
A bonded label makes more sense next to the barrels that earned it, so when a group asks about bond, we route toward distilleries that bottle one. Willett in Bardstown sells Old Bardstown in a Bottled in Bond version alongside its estate and 90 proof bottlings. Whiskey Thief in Frankfort lists a bottled-in-bond bourbon in its range, and guests there fill their own bottle from the barrel they like, which makes the single-distillery, single-season idea easy to see. Those two sit in different clusters, about 50 minutes apart, so a bonded day picks one side and builds three stops around it. Our custom-built Kentucky bourbon tours are planned that way, one route per group, from the questions the group brings.
A bonded day at Willett or Whiskey Thief is planned like the 3,000+ others we have run since 2012: for one group, with no other guests on board.
