The mash
bill
The grain recipe is the single best predictor of how a bourbon will taste. Learn to read it and you can call the style before the glass reaches your nose.
The four grains
Bourbon is legally ≥51% corn, but the rest of the recipe — the "flavoring grains" — is where style is decided. Click each:
The style spectrum, by grain
High corn → sweet and soft. High rye → spicy and dry. Wheat → gentle and rounded. Given a mash bill on a label or spec sheet, you can predict the glass before tasting — and the whole styles block (Sessions 8–12) is just this lesson, expanded one grain at a time.
Questions
Flashcards
Lock it in
From memory:
- What is the minimum corn requirement, and what does corn contribute?
- Contrast what rye vs wheat each bring to a bourbon.
- Why is malted barley in the mash bill at all?
- What does a "high-rye" bourbon taste like versus a "wheated" one?
- Why is the mash bill called the best predictor of style?
Fermentation
& sour mash
Between grain and still sits the quietest, least-understood flavor lever in bourbon: yeast and the sour-mash process. This is where fruit and funk are born.
Sour mash, sweet mash & yeast
Click through the fermentation levers:
Nearly all bourbon is made by the sour-mash process — it’s a consistency-and-safety standard, not a flavor style. Seeing "sour mash" on a bottle is a bit like seeing "made with water": true, but not distinguishing. The real fermentation variable you can taste is the yeast strain and ferment length, which shape the fruity, floral, sometimes funky ester profile.
Questions
Flashcards
Lock it in
From memory:
- What is the sour-mash process, and what is the "setback"?
- Is sour mash a flavor style or a process standard?
- Why do distilleries guard their yeast strains?
- How does sweet mash differ from sour mash?
- What does a longer fermentation tend to develop?
Distillation
Distillation concentrates the spirit — but the proof it comes off the still decides how much grain flavor and body survive into the barrel. A quiet rule with loud consequences.
How bourbon is distilled
Click through the distillation toolkit:
Two paths off the still
Column still + doubler (most bourbon)
- Continuous, efficient, consistent at scale
- Clean "low wine" off the column, refined in a doubler/thumper
- The standard Kentucky setup
- Great for reproducible house style
Pot still (craft / Scotch)
- Batch distillation, less efficient
- Retains more texture and grain character
- More variation batch to batch
- Common in small craft operations
The legal ceiling is 160 proof off the still and 125 into the barrel. But distillers choose where below those caps to land. The lower the distillation proof, the more grain flavor and oily body carry through; distilling near the cap yields a lighter, cleaner spirit. This single choice is a major reason two bourbons with identical mash bills can taste so different.
Questions
Flashcards
Lock it in
From memory:
- What still setup does most bourbon use, and what does the doubler do?
- What is the distillation proof ceiling, and why does it exist?
- How does distilling to a lower proof affect the final spirit?
- What is the barrel-entry proof cap?
- Why can two bourbons with the same mash bill taste different?