“Where does bourbon come from?”
“Well son, when a man and woman love each other very much, they share a special… Wait… Did you say bourbon?”
It’s a fair question. We all love our bourbon, but do we know how those humble kernels of corn become bourbon? What arcane arts allow those Master Distillers to transmute base grains into liquid gold?
You’re going to need a mashbill, which is the list of all the grains going into your mash and their relative proportions. Obviously, you’re going to use at least 51% corn (otherwise you aren’t making bourbon), but beyond that you can get creative. You can use rye, wheat, barley, bacon… Ok, maybe not bacon, but you get the picture. If you went 70% corn, 13% rye, 13% malted barley, and 4% wheat, you’d have yourself a decent mashbill.
Take all the grain, grind it up and toss it in a huge vat of water and give it a boil to loosen things up. If we were making beer, this would be our wort, but we’re not. You’re making bourbon and that sludge is your mash. If you have a bit of your last batch of mash laying around, you can toss that in as well to make sour mash (this helps ensure consistency across batches). Now dump some yeast in your mash and go find something else to do while the yeast converts the grain starch into alcohol. This could take a while.
Yeast done working? Congratulations, your mash has been promoted to wash. You’re going to take that relatively low-alcohol wash and distill it (separate the alcohol from the water). Most distilleries use a continuous (or column) still, but some still use the old pot (aka alembic or batch) still. If you’re bootlegging, a car radiator will also do in a pinch. You want to distill your mash to no more than 160 proof, otherwise it ain’t bourbon.
At this point, you’re going to need some barrels. They need to be made of oak, they need to be charred on the inside, and they need to be new (no reusing the barrels from your last batch). Charring the barrels converts some of the starch in the wood (yes, wood has starch) into sugars and other delicious chemicals that you will want in your bourbon. You’re going to take the nice clear spirit from your still and fill up your barrels. Then you’re going to throw all the barrels into the barrel house and wait.
How long do you have to wait? Well, that depends. There’s no legal minimum aging time. If you wait for at least two years and you don’t add any coloring, flavoring, or additional spirits, you’ll be allowed to call it Straight Bourbon Whiskey. If your straight bourbon whiskey has been aged for less than four years, you’ll have to put the age on the label. If you want to put the age on your straight bourbon whiskey bottle, you can only put the age of the youngest whiskey that went into the bottle. If you want to add non-bourbon spirits, you have to label it as “blended”.
So what’s going on while the bourbon is aging? Over time, the atmospheric conditions in your barrel house are going to change. It’s going to get hot in the summer and cold in the winter. The humidity is going to rise and fall. These changes outside the barrel are going to cause changes inside the barrel. The bourbon is going to expand and contract, moving in and out of the wood of the barrel. And every on every trip in and out of the wood, it’s going to pick up more of the color and flavor that the barrel has to offer. Some of your bourbon is going to evaporate (the angels’ share). And you, as the Master Distiller, will be keeping an eye on every barrel; waiting for the day when each one of them is ready to be dumped. Naturally, not all of your barrels will age the same and you’ll want to pay special attention to the barrels in the heart of your barrel house.
Now that you’ve got a really good barrel, you need to dump it. Generally you’ll dump a bunch of barrels together (think a few hundred of your 50 gallon barrels), dilute with water down to no less than 80 proof, and bottle it up. if you’ve got a few particularly good barrels (think 20), you may want to dump them together and call it a small batch bourbon. There’s no legal definition for small batch, but folks will know if you’re cheating. If you have one particularly outstanding barrel, you might want to bottle it by itself as a single barrel bourbon.
It’s a long road from grain to bottle. I, for one, am thankful for all the Master Distillers out there tending the barrels so I don’t have to. Believe me, I’ve brewed my own beer. You don’t want me in charge of making the bourbon.