How to Decode Four Roses Bourbon Recipes

From yeast strains to mashbills, we'll dive into what separates OESV from OBSK and beyond.

There’s definitely some science going on at Four Roses.

And that’s not terribly unique – basically every major distillery dabbles in proprietary yeast strain development, mashbill tinkering and of course, a healthy dose of blending. But from our research, we’re not sure that anyone goes as far in depth as Four Roses does in developing their yeast strains. They’re not shy when it comes to talking about them, but rest assured that the strains sit under lock and key at their facility. While mashbills and distillation techniques are vitally important in the overall flavor profile, they are much more easily replicated. According to Britannica, there are over 8,000 yeast strains that have been identified (and over 2,000 species), which makes ‘cracking the code’ on the yeast much more difficult. For Four Roses, this means having a unique proprietary advantage over competitors – that cannot be easily replicated.

The basic anatomy of a Four Roses recipe

When you get a Four Roses Single Barrel and it says ‘OESV’ or ‘OBSK’ on the tag or label, that’s just referring to the recipe that was used for that particular bottle. Four Roses has a total of ten recipes (which we’ll get to in a bit). But here’s the gist of what those letters mean on each recipe:


So for each recipe, you can expect to see:

  • 1 distillery designation
  • 1 mashbill
  • 1 designation (they’re all straight Bourbon)
  • 1 yeast strain

So what about this ‘OESV’ bottle? What can we expect? Firstly, it’s produced at Four Roses Distillery (as all recipes are), which gives us the first letter of ‘O’ (they are all ‘O’). It’s the ‘E’ mashbill, which should be less rye-forward and therefore a tad less spicy and more on the sweet side. Every recipe (and therefore, bottle) has a designation of ‘S’, which simply means straight Bourbon. In this particular example, we have the yeast strain of ‘V’. That would indicate that this bottle is going to have a rather fruity profile with the yeast strain imparting delicate fruit notes.

We made you a recipe cheat sheet.

Go ahead, give it a whirl. Select the recipe you find on the bottle and we’ll do all the lifting for ya!



Tasting notes: You’re gonna get delicate notes of fruit (pear, apricot) with a more rye-forward profile.

Yeast strain: Delicate fruit

Mashbill: High Rye (mashbill B)


Tasting notes: Baking spice and a more rye-forward profile.

Yeast strain: Slight spice

Mashbill: High Rye (mashbill B)


Tasting notes: You’re gonna get a lot of rich fruit notes and a rye-forward profile.

Yeast strain: Rich fruit

Mashbill: High Rye (mashbill B)


Tasting notes: You’re gonna get a bit of floral notes, and a spicy rye-forward profile.

Yeast strain: Floral essence

Mashbill: High Rye (mashbill B)


Tasting notes: You’re gonna get some nice fruit notes, a touch of mint (with the herbal yeast strain), and a rye-forward spicy profile.

Yeast strain: Herbal notes

Mashbill: High Rye (mashbill B)


Tasting notes: This is going to be delicately fruity, fresh and creamy.

Yeast strain: Delicate fruit

Mashbill: Low Rye (mashbill E)


Tasting notes: Baking spice and sweetness, full bodied.

Yeast strain: Slight spice

Mashbill: Low Rye (mashbill E)


Tasting notes: Fruity (red berries) and medium bodied.

Yeast strain: Rich fruit

Mashbill: Low Rye (mashbill E)


Tasting notes: Floral and fruity with a medium body.

Yeast strains: Floral essence

Mashbill: Low Rye (mashbill E)


Tasting notes: A bit fruity, but herbal and minty too. Nice and sweet.

Yeast strains: Herbal notes

Mashbill: Low Rye (mashbill E)

Want to know a bit more? Well of course you do, if you’re Bourbon Nerds like we are! Keep reading below to learn about the yeast strains and mashbills.

From left: A Four Roses Single Barrel store pick with the OBSO recipe, the single barrel bottle tag that shows the different profiles, and another single barrel with a recipe and age statement.

Let’s jump right into the yeast.

Figuratively, of course. Four Roses has 5 proprietary yeast strains, and speaking from experience, this is probably what makes the taste profile so different among their products. Each strain imparts different notes to each product, as shown below:

These flavor characteristics allow Four Roses to create bottles that can really be unique. Doing so allows different characteristics to mingle and create a particularly distinct flavor altogether. These strains, coupled with the mashbill for that recipe (which we’ll dive into next), is what makes the magic in each Four Roses bottling.

They leverage two mashbills.

In each of the recipes, you’re going to find either an ‘E’ or a ‘B’, and this letter stands for the mashbill that Four Roses puts in each recipe. Here’s what those are made up of:

The 75% corn in mashbill ‘E’ is what’s going to make things a bit sweeter in the bottles that utilize it. It’s likely you’ll get less of the sharper or spicier notes simply with the lack of rye – leaving a “smoother” profile overall, with less bite.

Mashbill ‘B’ is going to be a bit on the opposite end of the spectrum. It’s high rye, which means it’ll taste a lot more like…rye. This generally means that it’ll have a bit more spice characteristic in general; probably a bit peppery. This is good though, because it can really enhance some of the characteristics of the yeast strains, like in the ‘K’ strain. Additionally, it can enhance what would be a smoother and sweeter strain like ‘O’ or ‘V’ and impart some pepper spice, which would help give it that sweet/spicy balance.

You’re now a Four Roses recipe expert.

Go forth and shop in confidence now, fellow Bourbon Nerd. You know exactly what you’re getting in the Four Roses single barrel you see on store shelves. When you see ‘OESK’ or ‘OBSO’ you now know what you’re getting into! In truth, all of these recipes are really incredible and you cannot go wrong in getting any which one. So go forth, friends, and enjoy that bottle (responsibly). Cheers!

Meet the author
Homebar staff member
Kevin is the founder of Homebar.io. His enduring love for trying out different cocktail recipes and home bartending for friends is what led him to create Homebar. In addition to being a (very) amateur mixologist, he’s also a huge whiskey enthusiast and bottle collector. When he’s not voraciously learning about spirits and cocktail-making techniques, you can find him spending time with his family and his Golden Retriever, Molson.


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