“The DNA of Whiskey: Blog #44 - How Grain Selection and the Mash Bill Shape Everything in Your Glass”

Welcome back to Bourbon and BS, the blog and podcast where we dive deep into the world of spirits, one shot at a time. I’m Mike Foti, Founder and Director of the Bison Bourbon and Spirits Training Company — where my mission is simple: It’s to help you Master Spirits and Guide Choices.

“The DNA of Whiskey: Blog #44 - How Grain Selection and the Mash Bill Shape Everything in Your Glass”

Suggested pours for this episode — build a grain flight:

- A high-corn bourbon (95%+ corn) — New Riff Heirloom Corn for contrast

- A high-rye bourbon — Bulleit or Four Roses (high rye mashbill)

- A single malt Scotch — something approachable like Glenlivet 12 or Glenmorangie to represent malted barley

- A wheated bourbon — W.L. Weller or Larceny to show wheat’s effect directly

- Optional: a grain whisky like Bernheim to show what near-100% corn or wheat tastes like unaged

## SEGMENT 1 — COLD OPEN (2–3 minutes)

“Let me ask you something. You’re holding a glass of bourbon. You nose it — vanilla, caramel, a little fruit, maybe some spice. You taste it — warm, sweet, long finish. You think: that’s good bourbon.

But do you know why it tastes like that? Not the barrel. Not the water. Not the distillery’s Instagram aesthetic. I mean the actual starting point. The grain.

Because here’s the thing most enthusiasts — even experienced ones — don’t fully appreciate: before the still, before the barrel, before the bottling line and the beautiful label, there’s a field. There’s a farmer. There’s a kernel of corn or rye or barley or wheat. And the decisions made about those grains — which ones, in what proportions — are going to determine more about what ends up in your glass than almost anything that happens after.

Welcome to Bourbon and B.S. I’m Mike Foti. I have a degree in Laboratory Medicine and Biology. I’ve done fermentation and distillation training at Moonshine University in Louisville. I’ve grown things on a farm in Western New York. And I’ve been pouring whiskey professionally long enough to know that grain is where the story starts.

Today we’re going deep on two things that belong together: how individual grains shape flavor, and why distilleries treat their mash bill recipes like state secrets. By the end of this, you’ll never look at a whiskey label the same way again.

Let’s go.”

SEGMENT 2 — SETTING THE STAGE: WHAT IS A MASH BILL?

Let’s Establish some vocabulary before diving into the science.

“A mash bill — sometimes called a grain bill — is simply the recipe of grains used to make a whiskey. It tells you which grains are in the mix and in what percentages. That’s it. Simple concept. Profound implications.”

 The legal minimums — regulatory context:

“Now here’s where my love of spirits regulation comes in, because the rules actually matter here.

For a spirit to be called bourbon, US law requires a minimum of 51% corn in the mash bill. That’s the floor. Everything above 51% is the distillery’s choice.

For rye whiskey — 51% rye minimum.

For wheat whiskey — 51% wheat minimum.

For malt whiskey — 51% malted barley minimum.

For corn whiskey — 80% corn minimum, and here’s the kicker: it doesn’t have to go into new charred oak. That’s why corn whiskey and bourbon are legally different animals even though they share a primary grain.

Single malt Scotch? 100% malted barley, single distillery. That’s the whole grain bill right there — no blending of grain types, just variations in how the barley is processed.

The regulations set the floor. What distilleries build above that floor is where the art and science live.”

Why do the other grains matter?

“Corn is your base — your foundation grain in bourbon. But corn alone makes a spirit that’s sweet and relatively simple. The other grains — rye, wheat, malted barley — are what add complexity, spice, structure, and fermentable character. They’re called adjunct grains or flavoring grains depending on who you talk to. I prefer flavoring grains — because that’s exactly what they do.”

Transition: “So let’s meet them one by one. Because each grain has a personality. And once you understand those personalities, you’ll start tasting them in the glass.”

SEGMENT 3 — CORN: THE FOUNDATION

*Start with the dominant grain. There is nothing like farm fresh corn.  “I grew up around agriculture in Western New York. I’ve farmed with my family. I know what a field of corn looks like in August — that specific smell, the way the stalks move. There’s something grounding about understanding that this giant agricultural crop, the backbone of American farming, is also the backbone of American whiskey. It’s not an accident. It’s geography, climate, and history all at once.”

What corn brings to the glass:

Chemistry first:

“Corn is loaded with starch — specifically long-chain polysaccharides. During the mashing process, those starches get converted to fermentable sugars by enzymes — primarily amylase from the malted barley in the mash bill. As a lab scientist, I find this genuinely beautiful: you’re using one grain’s biological machinery to unlock another grain’s energy. It’s elegant biochemistry.”

Flavor profile:

“In the glass, corn contributes sweetness — a clean, round, approachable sweetness. Think vanilla, caramel, light stone fruit. It’s the reason bourbon is often described as accessible and crowd-pleasing. High corn mash bills — anything north of 70 or 75 percent corn — tend to produce softer, rounder spirits.

The highest corn content in mainstream bourbon? Mellow Corn and similar corn whiskeys push 80% and above. The result is almost candy-sweet — pleasant, but not particularly complex.”

The agricultural angle:

“One thing worth knowing: not all corn is the same. Most distilleries use yellow dent corn — the standard commodity grain. But a growing number of craft producers are experimenting with heirloom varieties: Bloody Butcher, Jimmy Red, and even Andea Black corn grown above 10,000 feet in south America. These open-pollinated varieties have different starch compositions and produce genuinely different flavor profiles. It’s the terroir conversation applied to grain — and it’s one of the most exciting frontiers in American whiskey right now.” Another frontier that continues to expand is yeast but that story is for another podcast.

Transition: “Corn gives you the foundation. The sweetness. The body. But on its own, it’s a little one-dimensional. That’s where the flavoring grains come in — and the first one changes everything.”

SEGMENT 4 — RYE: THE TROUBLEMAKER

“If corn is the reliable foundation — solid, sweet, dependable — then rye is the character actor who steals every scene. Rye is assertive. Rye has opinions. Rye will absolutely let you know it’s there.

And honestly? I respect that.” - What rye brings: - The chemistry:

“Rye is fascinating from a production standpoint — and I mean that as a lab scientist who actually finds fermentation chemistry interesting, not as a marketing line. When we ferment rye for rye whiskey, it has so much character we have to put a heavy lid on the fermentation tank or it will boil over. Now that character.

Rye grain contains compounds called pentosans — complex polysaccharides that absorb water and create a thick, viscous, almost gummy mash. Distillers call it ‘rye hell’ for a reason. High-rye mash bills are genuinely difficult to work with. The mash sticks, clogs equipment, and causes headaches throughout production.

That difficulty is part of why high-rye products often command a premium — and in this case, unlike some of the marketing premiums we’ve talked about before, the cost is real.”

Flavor profile:

“In the glass, rye delivers spice — black pepper, clove, sometimes a dry herbal quality. It also adds structure — a drier, more angular texture compared to corn’s roundness. That’s why rye-forward bourbons and straight ryes work so well in cocktails. The Manhattan, the Sazerac, the Old Fashioned — these classics were built around rye whiskey. The spice cuts through sweetness and bitters in a way that corn-dominant bourbons simply don’t.”

High rye vs. low rye bourbons:

“Here’s a practical tasting exercise I run in my workshops: put a high-rye bourbon — something like Bulleit or a Four Roses high-rye expression — next to a wheated bourbon like Maker’s Mark. Same category. Same legal requirements. Dramatically different personalities. The high-rye is spicy, angular, complex. The wheated is soft, round, approachable. Same corn base, different flavoring grain. That’s the mash bill doing its work right in front of you.”

Straight rye whiskey:

“And then there’s straight rye — 51% rye minimum, aged in new charred oak. Rittenhouse. WhistlePig. Michter’s. These are rye-dominant expressions where the grain’s personality is fully in charge. They’re not for everyone — they can be assertive to the point of challenging for palates trained on soft, sweet bourbons. But for those of us who appreciate complexity and a spirit that doesn’t apologize for itself? Rye whiskey is one of the great pleasures in the American whiskey canon.”

Transition: “So corn gives you sweetness and body. Rye gives you spice and structure. Now let’s talk about the grain that makes Scotch what it is — and that plays a quieter but absolutely essential role in every American whiskey ever made.”

 SEGMENT 5 — MALTED BARLEY: THE SCIENTIST IN THE GRAIN BIN

“Every whiskey in the world — bourbon, Scotch, Irish, Japanese — owes a debt to malted barley. Not always as a flavor grain. Sometimes purely as a biochemical tool. And understanding why requires about 90 seconds of enzyme chemistry that I promise will change how you think about every whiskey you ever drink.”

The malting process:

“Barley is malted by soaking the grain in water, allowing it to germinate — to begin sprouting — and then halting that germination with heat. Why? Because during germination, the barley produces enzymes. Specifically, alpha and beta amylase — the same enzyme family that’s in your saliva right now, breaking down the starch in whatever you last ate.

A brief history side track.  Historically the malting process was done by hand, aka floor malting, which I have done at the Springbank distillery in Campbelltown Scotland on the Kintyre Peninsula. They hand load a massive tank with barley, fill it with water and let it soak for 48 hours or so. After soaking you shovel it out of the malting tank by hand and into wheel barrels.

Now the real work begins. The soaked, very heavy barley grains are spread out on a massive floor the size of a quarter of a football field, at a depth of about 4 to 6 inches, with 4 foot by four foot holes at one end. It is left their for 2 to 3 days so the germination process can get into full swing. As these seeds start to grow they produce little rootlets that would grow together making the entire floor into a barley carpet which could not be used to make whiskey.  SO, men used to use wood shovels to turn the barley every 8 or so hours to prevent this from happening. The term monkey shoulder came from the shoulders of the men that turned the barley because they developed massive muscle on the shoulder of their dominate side which they used to manage the shovel.

Now if the germination process was left to run to long, all the starches and sugar needed to produce whisky would be consumed. After 2-3 days the germinating grains are pushed down the holes I mentioned earlier into kilns where they are exposed to heat to kill the embryonic plants that would have consumer the sugar but the seeds no contain the enzyme needed to breakdown the starches and sugars in any milled seeds they come in contact with to produce the final whiskey product. Suffice it to say I was happy to only work on the malting floor for a few hours.

Sorry for the side step, These amylase enzymes are the key to converting grain starch into fermentable sugar. Without them, your mash is just a vat of wet grain. With them, it becomes the sweet liquid — the wort — that yeast can ferment into alcohol and congeners.

In bourbon production, malted barley typically makes up only 5 to 15 percent of the mash bill. But it’s doing the enzymatic heavy lifting for the entire batch. The corn brings the starch. The malted barley converts it. It’s a partnership — and a beautifully efficient one.” In the USA many distilleries add additional enzymes but that is forbidden by UK law.

Flavor contribution:

“Beyond its enzymatic role, malted barley contributes its own flavor character — particularly in single malt Scotch where it’s the only grain in play.

Unpeated malted barley delivers cereal notes — biscuit, digestive, light nuttiness, sometimes a gentle honey quality. It’s a softer, more delicate flavor profile than either rye or corn. In bourbon, where malted barley is a small percentage, its flavor contribution is subtle — a background nuttiness, a slight bready quality beneath the corn sweetness.

In single malt Scotch, it’s everything. The entire flavor architecture — from the light, floral Speyside style to the rich, complex Sherried Highland expressions — is built on malted barley and the interaction between that grain, the water, the yeast, and the barrel.”

The peat conversation — and my take:

“Now I have to address peat, because it’s the most dramatic thing that happens to malted barley in Scotch production.

I have started that fire made of peat at the Springbank Distillery.  The green malt is dried in a kiln over burning peat rather than a standard heat source. The smoke from the peat permeates the grain and introduces phenolic compounds — specifically guaiacol and syringol — that create that distinctive smoky, medicinal, sometimes almost iodine-like character associated with Islay Scotches.

And here’s my honest take, speaking as someone who has tasted a lot of whisky professionally: I find most heavily peated whiskies overpowering. Not because the chemistry isn’t interesting — it absolutely is. But because for me peat, at high levels, tends to overwhelm everything else the distillery has created. The grain character, the distillery’s house style, the cask influence — all of it gets buried under smoke.

There are exceptions. A mild or modest peat level — Port Soy from Glenglassaugh or the Highland Park approach, a light touch — can add complexity without dominating. Oban 14 another example of peated whiskey I drink once in a while. But the race to the highest PPM counts in some corners of the Scotch world strikes me as a case of process overwhelming product. You’re tasting the fuel source, not the whisky.”

“Corn, rye, wheat, and malted barley. Four grains with four distinct personalities. Now let’s talk about the one that gets the least attention and deserves considerably more.”

SEGMENT 6 — WHEAT: THE QUIET ACHIEVER

Wheat is my personal preference in the bourbon flavoring grain territory — let that come through.

“I’ll be honest with you — wheat is my grain. Not exclusively, but when I’m reaching for something to unwind with after a long day — after a shift, after a workshop, after chasing Jax and Rip around the yard before they eat something they shouldn’t — a well-made wheated and/or sherried bourbon or scotch is where I land more often than not.

There’s a reason for that. And it’s in the grain.”

What wheat brings:

Chemistry:

“Wheat, like corn, is a starch-dense grain that relies on the malted barley’s enzymes for conversion. But its starch composition is different from corn — the resulting fermentation produces a different ester profile, which means different flavor compounds in the final spirit.”

Flavor profile:

“Where rye is bold and assertive, wheat is soft and accommodating. Wheat-based spirits tend toward a gentle sweetness — softer than corn, more delicate. Bread-like, sometimes floral, occasionally a light honey quality. The texture is often described as silky or creamy.

And critically — wheat steps back. It doesn’t dominate. It lets the corn, the yeast character, and especially the barrel do their work without competing. That’s not weakness — that’s sophistication.”

The Pappy effect:

“Here’s a name that gets thrown around in bourbon circles constantly: Pappy Van Winkle. Buffalo Trace’s Van Winkle line — along with W.L. Weller, Old Fitzgerald, and Maker’s Mark — are wheated bourbons. The Pappy mystique is built on multiple things: age, rarity, marketing, and genuine quality. But the grain bill is part of the equation. The softness and approachability of a well-aged wheated bourbon is something that high-rye expressions simply don’t deliver in the same way.

Here’s the thing I tell my workshop students: you can get most of that wheated bourbon experience for a fraction of the Pappy price. W.L. Weller is the same basic mashbill from the same distillery. Larceny from Heaven Hill is beautifully made. Old Fitzgerald Bottled in Bond, when you can find it, is exceptional.

The grain is the same. The mystique is not. And mystique, as we’ve discussed before, is a marketing construct — not a flavor compound.”

 SEGMENT 7 — THE MASH BILL AS RECIPE: WHY DISTILLERIES GUARD THEM

This is the investigative, consumer-advocacy segment — where the LEO and pharma marketer merge.

Open with the pharmaceutical parallel:

“In my 40 years in pharmaceutical sales and marketing, I sold proprietary drug formulations. The active ingredient might be publicly known — the molecule itself is on-patent. The formulation — the specific combination of excipients, the delivery mechanism, the ratios — that’s protected intellectual property. That’s the competitive moat.

Distillery mash bills work the same way. The grains themselves are commodity products. Corn, rye, barley, wheat — you can buy them anywhere. But the specific ratios, the sourcing decisions, the processing parameters — that’s the recipe. And recipes, in the spirits industry, are guarded with extraordinary care.”

What distilleries actually protect:

Published vs. proprietary:

“Some distilleries are transparent about their mash bills. Four Roses publishes their two mash bill recipes — a high-rye and a low-rye — and combines them with five different yeast strains to create ten distinct recipes. They’ve built their entire brand identity around that transparency. It’s smart marketing, but it’s also genuine education.

Buffalo Trace publishes that their Mash Bill No. 1 is lower rye and No. 2 is higher rye — but doesn’t publish the exact percentages. You can taste the difference. You just can’t replicate it precisely.

Others are famously secretive. Wild Turkey has never published their exact mash bill. Heaven Hill guards their recipes carefully across multiple brands. The exact corn-rye-barley ratios for many of the most iconic bourbons in existence are not publicly known.”

Why it matters competitively:n “Here’s why distilleries are not being paranoid about this — they’re being rational.

If your mash bill is public knowledge, a competitor can replicate your grain recipe and produce a functionally similar spirit. They’d still need your yeast strain, your still geometry, your water source, your barrel program — but the grain bill is the starting point. Remove that advantage and you’ve handed a competitor the first page of your playbook.

In an industry where brands are built over decades and where production decisions made today won’t be tasted for 8 to 12 years, protecting your recipe isn’t secretiveness. It’s survival.”

The sourcing dimension:

“There’s another layer here that doesn’t get discussed enough: grain sourcing. Two distilleries could theoretically use the identical mash bill ratios and produce different spirits because their grain comes from different suppliers, different regions, different soil conditions.

Terroir is a concept the wine world takes seriously. The whiskey world is catching up. A growing number of craft distilleries are doing estate grain programs — growing their own grain on their own land and distilling it. The flavor differences are real and measurable. When I was farming in Western New York, I understood intuitively that what comes out of the ground reflects what went into it — the soil, the weather, the variety. That same principle applies to distillery grain.”

The MGP conversation:

“And here’s where I’m going to name something that the industry doesn’t always love to discuss: sourced whiskey.

A significant portion of American whiskey — particularly in the craft and boutique segment — is distilled not by the brand on the label but by a contract distillery. MGP Ingredients in Lawrenceburg, Indiana is the most prominent. They produce bourbon and rye for dozens of brands that bottle and market under their own labels.

Is that wrong? Not inherently. MGP makes genuinely excellent whiskey. Their 95% rye mash bill, in particular, is exceptional spirit that shows up in multiple well-regarded brands.

The issue is transparency. When a brand implies — or outright claims — craft distillation and small batch production while sourcing commodity spirit from a contract distiller, that’s where my law enforcement background kicks in. That’s misrepresentation. And it’s rampant enough in the industry that the TTB has been under pressure to tighten labeling requirements around distillery of origin.

As a consumer, look for ‘distilled by’ versus ‘bottled by’ on the label. They are not the same thing.”

 SEGMENT 8 — PUTTING IT ALL TOGETHER: TASTING THE GRAIN

Practical and personal — bring the science into the glass.

The grain flight exercise:

“Here’s the exercise I want you to try — and if you come to one of my Full-Day Bourbon Workshops at Buffalo Distilling Company in 2026, we do exactly this together.

Build yourself a grain flight. Four whiskies, one for each flavoring grain profile:

A high-corn, wheated bourbon — Maker’s Mark or W.L. Weller. This is corn and wheat doing their thing together. Soft, round, approachable.

A high-rye bourbon — Bulleit or a Four Roses single barrel from their high-rye mashbill. Now you’re tasting what rye adds to that corn base. Notice the spice. Notice the texture change — it’s drier, more angular.

A straight rye — Rittenhouse Bottled in Bond is my go-to recommendation for this exercise. Affordable, honest, and rye-dominant enough to make the point clearly. Now the rye is in charge. Everything else follows.

And a single malt Scotch — something approachable, not peated. Glenlivet 12 or Glenfarclas 10. Now you’re tasting what malted barley does when it’s the only grain. The cereal character, the gentle sweetness, the way the distillery’s house style comes through without corn or rye competing for attention.

Taste them in that order. Nose each one before you taste. Add a few drops of water to open them up. Notice what’s different. Notice what’s similar. You’re not just tasting four whiskies — you’re tasting four different grain personalities.”

What to look for:

“Sweet and round? That’s corn.

Spicy and angular? That’s rye.

Soft and silky with a step back? That’s wheat.

Biscuity, cereal, delicate? That’s malted barley.

These aren’t just abstract descriptors. They’re the flavors of specific organic compounds produced by specific grains during fermentation. The science and the pleasure are the same thing.”

SEGMENT 9 — CLOSE --“I started this episode by saying grain is where the story starts. I want to close by saying something a little different: grain is where your education as a whiskey drinker gets serious.

Anyone can learn to prefer one whiskey over another. That’s just personal taste — and personal taste is valid and doesn’t need a justification. But understanding why you prefer it — being able to trace that preference back to a grain, a ratio, a production decision — that’s what separates an enthusiast from someone who just drinks.

I have a degree in Medical Technology. I’ve spent 45 years in law enforcement. I’ve done fermentation training in Louisville and distillation training in North Carolina and Scotch education in Campbeltown and Speyside. And I’m still learning. Every bottle teaches you something if you’re paying attention.

That’s what Bourbon and B.S. is about. Not telling you what to drink. Giving you the tools to figure that out for yourself — and to spend your money on bottles that genuinely deserve it.

Because here’s the thing my law enforcement background taught me: an informed person is a harder person to deceive. And the whiskey industry — like every industry — has its share of people counting on you not knowing the difference between a high-corn soft mash and a marketing story on a pretty label.

Know the grain. Know the bill. Know what’s in your glass.

No BS.” Here is your challenge:**

“This week: build the grain flight I described. Four bottles, four grain profiles. Taste them side by side. Come back and tell me which grain personality speaks to you most — and whether it surprised you. Find me at WNYWhisky on Facebook or visit us at bisonbourbonspiritstc.com.

And if you want to do this exercise with me in person — our Full-Day Bourbon Workshops are launching in 2026 at Buffalo Distilling Company, 860 Seneca Street, Buffalo, New York. Details on the website.”

Conclusion:

Thanks for joining me on this whiskey deep dive!

Whether as a beginner discovering new flavors or an aficionado pursuing perfection, the journey always has another fascinating glass to offer.

Join me at The Buffalo Distilling Company for a Deluxe Tour and Tasting or Whiskey Workshop by signing up on my website to experience a Buffalo-made bourbon firsthand.

Special shout out to the BDC for the use of their distillery for tours, tastings and the Whiskey Workshop.

Again, Please leave questions or comments on my website at bisonbourbonspiritstc.com, that’s b i s o n b o u r b o n s p i r i t s t c.com

Disclaimer: This podcast provides general information and entertainment. Always drink responsibly, and consult local regulations before imbibing. This podcasts is meant for listeners who are of legal drinking age only.

I’ll be back next time with another deep dive. Until then, check out the blog, explore the merchandise, and join me for a workshop or tasting at Buffalo Distilling Company.

Until the next podcast, keep sipping, keep exploring, and remember: good whiskey is like a well-crafted story. Do you “Love Bourbon & B.S.? Tell a friend.

We’re trying to grow this thing the old‑fashioned way—one honest pour and one honest listener at a time.”

Cheers to Bold Spirits and Curious Minds!

SHOW NOTES TEMPLATE

Episode: The DNA of Whiskey — How Grain Selection and the Mash Bill Shape Everything in Your Glass

Bourbon & B.S. | Bison Bourbon & Spirits Training Company

Mike Foti — Clinical Laboratory Scientist, 40-year pharmaceutical executive, 45-year law enforcement officer, and internationally credentialed spirits educator — goes deep on the grains that make whiskey what it is.

What we cover:

- What a mash bill is and why the legal minimums matter

- Corn: the foundation grain, its chemistry, and the emerging heirloom variety movement

- Rye: why it’s the troublemaker of the grain bin, and why that’s a compliment

- Malted barley: the enzymatic engine of every whiskey ever made — and Mike’s honest take on heavily peated expressions

- Wheat: the quiet achiever, the Pappy effect, and how to get that experience without the price tag

- Why distilleries guard their mash bill recipes like pharmaceutical trade secrets

- The MGP sourcing conversation and how to read a label for distillery of origin - The four-grain flight tasting exercise you can do at home

Build your grain flight:

- Wheated bourbon: W.L. Weller Special Reserve or Maker’s Mark

- High-rye bourbon: Bulleit Bourbon or Four Roses Single Barrel

- Straight rye: Rittenhouse Bottled in Bond

- Single malt Scotch: Glenlivet 12 or Glenfarclas 10

Read the companion blog post: bisonbourbonspiritstc.com/blog

Join a workshop: Full-Day Bourbon Workshops launching 2026, Buffalo Distilling Company | 860 Seneca Street, Buffalo, NY,  bisonbourbonspiritstc.com/registration

**Connect with me:, Facebook: facebook.com/WNYWhisky, LinkedIn: linkedin.com/in/MichaelAnthonyFoti

Drink curiously. Taste scientifically. No BS.

Get Outlook for iOS