Four Roses Recipe Codes Explained: What OESK, OBSV & the Others Mean

Four Roses does something no other major bourbon distillery does: it produces ten entirely distinct bourbon recipes, made from a combination of two mash bills and five proprietary yeast strains, then blends or single-barrels them into its full range. Once you understand the four-letter recipe codes, you can predict roughly what any Four Roses release will taste like before you open it.

How the Code Works

Every Four Roses recipe code follows the same four-letter format: O + [mash bill letter] + S + [yeast letter].

• O is a fixed prefix used across every Four Roses recipe — it doesn't vary.
• The second letter identifies the mash bill: E for the high-rye recipe (75% corn, 20% rye, 5% malted barley) or B for the lower-rye recipe (60% corn, 35% rye, 5% malted barley).
• S is a fixed marker for "straight" bourbon — it also doesn't vary.
• The fourth letter identifies which of five proprietary yeast strains was used, each contributing a distinct flavour signature.

The Five Yeast Strains

• V — Delicate fruit
• K — Slightly spicy
• O — Rich fruit
• Q — Floral, fragrant
• F — Herbal

Combine two mash bills (E or B) with five yeast strains (V, K, O, Q, F), and you get ten total recipes: OESV, OESK, OESO, OESQ, OESF, OBSV, OBSK, OBSO, OBSQ, and OBSF.

What the Codes Mean in Practice

The standard Four Roses Yellow Label (the entry-level bottle) is a blend of all ten recipes, giving a broad, balanced profile that samples a bit of everything the distillery makes.

Four Roses Small Batch Select and the annual Limited Edition Small Batch releases blend a smaller number of hand-selected recipes — often leaning toward specific codes chosen to hit a particular flavour target for that release, which is why Limited Edition Small Batch varies noticeably from year to year even under the same name.

Single barrel releases and private barrel picks, by contrast, come from exactly one recipe — meaning the code printed on a single barrel bottle tells you precisely which mash bill and yeast strain shaped everything in the glass. OBSV (low-rye, delicate fruit) and OBSK (low-rye, spicy) are among the most commonly seen single barrel codes at retail, while rarer codes like OESO are more actively sought by collectors specifically because they show up less often in single barrel form.

Why This System Is Unique

No other major American whiskey producer publishes this level of recipe detail, or actually varies mash bill and yeast combination this extensively within one brand. It turns Four Roses collecting into something closer to wine appellation-chasing — enthusiasts track which codes they've tried, compare private barrel picks by code, and use the system to predict flavour before buying, in a category where most other brands offer no equivalent transparency at all.

Next time you see a Four Roses single barrel bottle, check the code on the label — it's telling you exactly what to expect before you even open it.