Comparing components that differ mainly in one controlled factor makes sensory differences easier to interpret than comparing bottles that vary simultaneously in mash bill, yeast, age, proof, barrel, and producer.
Commercial bottles rarely isolate a single production variable, and maturation can overwhelm recipe-level differences. The method requires explicit confound notes and cautious conclusions.
Four Roses’ two-by-five recipe matrix illustrates controlled component design. Consumer blenders can approximate the logic by building pairs that hold most variables steady, tasting them blind, and recording remaining confounds. These comparisons improve role assignment and prevent causal stories from being inferred from uncontrolled bottle differences.
Methodological synthesis; it does not claim the official flavor descriptors are independently validated. September 6 Captures update: The Milam & Greene split-location account supplies a practical comparison case, but the bottles differ in native proof and no controlled, replicated factorial sensory design is reported. Treat it as an illustration of why confounds must be recorded, not as a validated climate-effect experiment.
No access / Whiskey Zettels Database (USWA)
A Zettel is one durable idea in your own words—not a quotation, source summary, or draft-book claim.
Atomic idea
State one complete idea. It should be understandable on its own and specific enough to connect to other notes.
Reasoning
Explain why the idea is true or useful in Rationale and Implications. Record meaningful objections or exceptions in Counterpoints.
Provenance
Connect one or more Literature Notes. Direct source relations are legacy-only; trace evidence through the literature-note and excerpt chain.
Connections
Apply approved Tags for retrieval and one or more Themes only when the note genuinely advances those interpretive threads.
Maturity checklist
Captures evidence update — September 6, 2026
The Milam & Greene split-location account supplies a practical comparison case, but the bottles differ in native proof and no controlled, replicated factorial sensory design is reported. Treat it as an illustration of why confounds must be recorded, not as a validated climate-effect experiment.
How Much Does Climate Affect Bourbon Aging? Milam & Greene Has “The Answer” — full article analysis.