Comparison: Two Four Roses Barrel Strength Single Barrels – OBSK & OBSO

Selected by K&L (2019)

MASH BILL – 60% corn, 35% rye, 5% malted barley

PROOF – 122.8

AGE – 8 years 2 months

DISTILLERY – Four Roses Distillery

PRICE – $82

“Ask The Angles” selected by Bitters & Bottles (2020)

MASH BILL – 60% corn, 35% rye, 5% malted barley

PROOF – 109.6

AGE – 8 years 11 months

DISTILLERY – Four Roses Distillery

PRICE – $82

This is another in a series of Four Roses posts, tracking my journey with the brand via their single barrel store pick releases. My ongoing experiment in comparing several of the Four Roses recipes over time, while my palate continues its constant evolution, is now closing in on its apparent end. After these two bottles, only one remains…!

I open a new bottle as the previous draws toward its final pours. The two bottles I have open at any given time vary by only one of the recipe’s elements, whether the mash bill or yeast strain. I’ve been less strict about matching age.

I’ve already posted notes about this particular OBSO release. Now the bottle is almost dry, so I’m comparing it to this more recently uncorked OBSK, itself the next in line on my fourteen bottle line-up:


OESO, 10 years 11 months, 105 proof, picked by Plumpjack Wines & Spirits

OESV, 9 years 11 months, 107.4 proof, picked by Plumpjack Wines & Spirits

OBSV, 8 years 8 months, 121.6 proof, picked by K&L

OBSO, 11 years, 110.2 proof, picked by Ledger’s Liquors

OBSV, 10 years 10 months, 127.2 proof, picked by K&L

OBSK, 10 years 9 months, 120 proof, picked by Bounty Hunter

OESK, 10 years, 110 proof, picked by K&L

OESV, 10 years, 122.6 proof, picked by K&L

OESK, 14 years, 113.4 proof, Elliott’s Select 2016 Limited Edition

OESV, 10 years 8 months, 112.8 proof, picked by Ledger’s Liquors

OBSV, 12 years, 105 proof, picked by Healthy Spirits


OBSO, 8 years 11 months, 109.6 proof, picked by Bitters & Bottles

OBSK, 8 years 2 months, 122.8 proof, picked by K&L


OBSO, 8 years 10 months, 106.8 proof, picked by the Single Barrel Project

These two bottles use the same mash bill (B), but differ in the yeasts used (K verses O) as well as 9 month in age. The proofs vary by 13.2 degrees. And their warehouse placements are different. That last bit is a level of detail I’ve not yet endeavored to track. There are Four Roses fans who do track warehouse stats, however. To that end, for those interested, a quick review of how to read the Four Roses single barrel label:

OBSK (left) and OBSO (right)

These little strips placed toward the front-bottom of the bottles are the standard Four Roses single barrel label referencing the exact barrel. Using the OBSK (on left above) as an example, reading from left to right:

61.4% — This bourbon was bottled at its natural barrel strength of 61.4% ABV, or 122.8 Proof.

KE — The barrel was stored in Warehouse K, on its east side. Warehouses have their micro-climates. You might find you like what tends to happen to bourbons stored in one warehouse versus another, and even one side of the warehouse versus another.

63-6D — The barrel was stored on Rick 63 (a rick is a vertical stack of shelves, or, tiers) Tier 6 (Four Roses uses ricks built of 6 tiers), and was the 4th barrel from the front—the letter D being 4th in the alphabet. The most pertinent aspect here is the tier. Tier 1 is at floor level, for example, and tier 6 is the top-most level. This matters because heat rises, and temperature impacts evaporation during the aging process. The warmer the air the more liquid evaporates, and the more concentrated the alcohol and flavors are in what remains. Given this K&L barrel aged on the top level, Tier 6, it’s no surprise that its proof is 122.8. You’ll notice the OBSO in today’s comparison was aged on Rick 83, Tier position 1K—the lowest level tier—and so its proof is lower at 109.6.

And this label is the custom label generated for the store that picked the barrel. It’s always affixed to one side of the bottle:

The store can choose what to include on it. In the above example, K&L is the store in question and included their logo. They included the date their barrel was bottled, as well as the mash bill recipe and age.

The age of this barrel is listed at 8 years 2 months. Age is typically rounded to the lowest month. So this barrel may literally be 8 years, 2 months and 29 days, for example.

In the four-letter recipe code, the first O and the S never change—the O referring to the Four Roses Distillery in Lawrenceburg, KY, and the S to the whiskey being “straight” (i.e. aged at least 2 years).

The second letter refers to one of two mash bills: B (60% corn / 35% rye / 5% barley) or E (75% corn / 20% rye/ 5% barley).

The fourth letter refers to one of five yeast strains—F, K, O, Q, V—each providing their own impact on flavor. Four Roses attaches a tag to the neck of their single barrel bottles featuring this handy at-a-glance recipe guide, with very general tasting notes:

Four Roses fas will notice in my running list of bottles above that four of the total ten recipes are missing: OBSF, OESF, OBSQ, and OESQ. Prior to this experiment, I’d already found the F and Q yeasts didn’t appeal to me more often than not, so I limited my experiment to the O, K, and V yeast strains. Tastes change, of course. Perhaps my next experiment will be to revisit those four recipes I’ve neglected!

But for now, here we are. I’m five months into this OBSO’s life and at its very final pours, and one month into this OBSK’s life and still at its initial pours. Here are some brief notes taken in traditional Glencairns. Given the steep difference in proof, I first tasted through the OBSO, then the OBSK, and then both side by side. These notes combine those three steps.


OBSO – toasty sienna-oranges

OBSK – toasted oranges

BOTH – there is something very relaxing about their colors


OBSO – soft cinnamons and wood spices laced with caramel, strong and yet very gentle and relaxed, with faint fruits like raspberries and dried strawberries

OBSK – oak spice on thick caramel, bright cinnamons, with a faint warm baked fruit note like apricot, everything thicker and more forceful than the OBSO, like a darker storm brewing with weirdly warm winds


OBSO – grittier than on the nose, with stronger oak wood and spices dominating the cinnamons, caramel, and fruit notes, and now some meaty orange peel in the mix

OBSK – after an initial hit of rich caramel the spiciness from the proof erupts momentarily, then subsides leaving seared oak, toasted cinnamon, the caramel, some cherry, and just a hint of the baked apricot now more syrupy


OBSO – warm and prickly in a gritty way, oaky, dry caramel on a cinnamon roll, a faint dark meaty orange peel note hovering in the background

OBSK – gently biting heat, caramel-laden cinnamon roll, a lingering sweet tang from the syrupy baked apricot


OBSO – drier now than five months ago (and it was already quite dry back then!). It’s a fairly refined oak and spice experience. With so little left in the bottle I better finish it off soon before it dries out entirely…!

OBSK – intense without overwhelming my palate, dry overall but with the rich caramel and juicy apricot notes adding sweetness


OBSO – Yes. For the sake of the journey. But I do prefer more sweet fruit and candy notes to pair with the drier oak and spices.

OBSK – Yes. For the sake of the journey. But after thirteen+ Four Roses barrel strength SiBs I now know I prefer proofs in the 105 to 115 range. These 120+ proof outings can come off too burnt for me in combo with the oakiness.

These are easily relatable to one another. Sharing the same mash bill and very similar ages, their differing yeast strains and proofs offer variations on a dry oak theme. They are refined, and solid. I appreciate that aspect of them both. But they do leave me hankering for sweeter notes to add to their complexity.

As noted above, I have one bottle left in my line up—another OBSO, aged 8 years 10 months and bottled at 106.8 proof. It might have been logical to try it next to the current OBSO, which is just one month older and 2.8 proof points hotter. But having gone this far with varying the recipes by one element, why stop now?

In any case, rather than another OBSO or OBS-anything, I do now wish I had an OESK to eventually try next to this recently opened OBSK. Something I’m realizing this time around more than ever is that, although I greatly appreciate variations on oak flavors, ultimately I prefer a complexity of sweet and dry aspects over this recent series of drier, oakier outings. The higher-rye B recipe by nature lacks the sweetness of the E recipe’s 75% corn.

It’s taken me a while. And the journey has definitely been worth it overall. But with the price on these Four Roses store pick SiBs continuing to climb, it’s good to now know that if I do make the investment in the future I can better the odds of my having an experience most to my liking if I focus on the OESV, OESK and OESO bottlings, aged on those lower tiers that yield lower proofs.

So this prolonged experiment is doing exactly what I’d hoped: helping me to understand in greater detail my preferred flavor profile. It’s also helped me parse out other Four Roses offerings, like their annual limited editions—now so expensive and sought after it’s ridiculous. So from a consumer perspective, my experiment has also been useful. Going forward I can be more confident and choosey in my buying with Four Roses. It’s a great brand. But there are more fish in the Bourbon Sea than dollars in my bank account, so, it helps to make informed purchases.

Until it’s time to crack that last OBSO, cheers!

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