Old school, meet new school.
Bourbon and scotch are two of the most popular sub-categories of distilled spirits. The first thing we should point out — they’re both whiskeys… or whiskies…
Is whisky a whiskey, with or without the ‘e?’
We’ll answer this and many other questions in this post.
Like the ancients, we’ll attempt to ‘distill’ millennia’s worth of information into one digestible article for you to enjoy.
Table of Contents
The Key Differences Between Bourbon and Scotch
The first — and perhaps most important — difference between Scotch and Bourbon is where each is made.
Scotch can be made in only one place — Scotland. And bourbon can only be made in one place — the United States. Whiskey made elsewhere — even to the exact same standards — cannot use either term to describe the product because of international treaties.
Another difference between the two is the emphasis on the type of grains in the mash recipe.
Bourbon must be made from at least 51 percent corn. Scotch can be made from various grains, but traditionally there is a considerable emphasis on malted barley. In fact, single malt scotch must be made from 100 percent malted barley by law. More on that in the ‘Types of Scotch’ section, below.
Let’s talk about that ‘e.’
Whiskey is whisky. Both spellings describe the same liquor type, and there is no hard and fast regulation on the spelling. But by tradition, American distillers use the spelling ‘whiskey,’ while Scots distillers use ‘whisky’ — sans ‘e.’
The answer has to do with market differentiation between Irish and Scots distillers during the turn of the 20th century. It’s a fascinating story, but we won’t go into it here. Perhaps another time…
When asking ‘Which came first?’ the answer is they’re not even close. In fact, whisky-making in Scotland predates the arrival of the first Europeans on the North American continent!
The art of distillation likely evolved independently on different parts of the globe throughout human history. At the surface, distillation describes the act of turning liquids into vapors so they can be isolated from the original solution. In the case of distilled spirits, the solution is any alcoholic beverage, and vaporizing the alcohol is a way of separating it from its original source — whether wine, beer, cider or mead.
The most well-documented discovery of the distillation process — and the one that led directly to the distillation of whiskey in Europe — began among the caliphate societies of the Middle East and Northern Africa. There, Islamic scholars were a bright spot during the Medieval period, maintaining the search for enlightenment, philosophy and scientific discovery while the Western world was plunged into the Dark Ages.
Scholars discovered that by heating wine, capturing the vapor, and cooling the gas so that it condensed back into liquid, they were left with a clear liquid that consisted of concentrated alcohol.
In fact, the word ‘alcohol’ has its origins in the Arabic words ‘al Kohl.’ If it seems strange that abstemious Islamic scholars discovered how to distill spirits, consider their goal was to advance the medicinal and cosmetic sciences. The original Arabic term describes the practice of sublimation — finding the essence, or ‘spirit,’ of a mineral, compound or solution.
Traveling monks learned the practice of distillation from Islamic clerics and brought it back to Europe. There, they used the practice to distill wine into the clear ‘Eau de Vie’ — Latin for ‘the water of life.’ When monks reached the British Isles — where brewing traditions outweighed winemaking — it was applied to beer. By distilling beer, they were left with a clear distillate ‘Uisge Beatha’ — Scots Gaelic for ‘the water of life,’ the origin of the modern anglicized word ‘whisky.’
Historians debate the exact date and location of the earliest whisky production, but Scots were likely creating spirits using crude distillation techniques about the year 1000 AD.
Much later — in the mid 18th century — distillers from Scotland, Ireland and Wales were among the European immigrants pushing the frontier westward in North America. These settlers carried with them whisky-making traditions from the Old World that eventually evolved into a corn-based whiskey called bourbon.
How Whiskey is Made
Fermentation relies on sugars. To produce alcohol, yeast consume sugar molecules and release CO2 and ethyl alcohol as a result. This occurs in nature when overripe fruits are exposed to ambient yeasts in the environment, and the result is fermentation on the vine. You may have seen humorous videos of drunk animals as evidence of this phenomenon.
Our human ancestors were early to pick up on this.
Many of the first alcoholic drinks found by archaeologists were mead, made from a mixture of honey and water. The natural sugars created by bees are easily digestible by yeast, so fermentation happens naturally. This knowledge was applied to wine, where fruit sugars were combined with water to create a solution perfect for fermentation.
As civilization and horticulture evolved to incorporate the harvesting of cereal grains, fermentation followed. But these grains contain starches — not sugars — which are not naturally digestible by yeast.
An extra step called saccharification is needed to convert the long starch molecules inherent in cereal grains into edible sugar molecules. In this step, cereals are milled and combined with water and cooked, releasing enzymes in the grains that facilitate this process.
Because of the abundance of enzymes found in malted barley grain, brewing traditions in Scotland and elsewhere rely heavily on its use. Homebrewers will note that the use of malted barley in any brew will likely increase the pre-fermentation BRIX reading — a measure of yeast activity potential. As a result, the beer at the end of fermentation will likely have a higher alcohol by volume percentage.
Once beer was invented, the next step was to distill it into a spirit with a higher percent alcohol.
Using a still, distillers can separate the alcohol from the beer, wine or other fermented beverage. By distilling wine, you can get eau de vie, grappa, Armagnac, cognac, pisco and other products. Apple brandy and calvados are made by distilling cider.
And when you distill beer, you get whiskey.
The next major difference between scotch and bourbon is the way they are matured.
Bourbons — along with Rye whiskeys and Tennessee whiskeys like Jack Daniel’s — must be matured in new American charred oak barrels. The requirement for American whiskeys has created a huge secondary market of charred oak containers that are then shipped out of country to be used many more times to mature spirits. In addition to Scotland, these barrels are also used in the production of many types of whiskey, including Japanese whisky, Canadian whisky and Irish whiskey.
[RELATED: Bourbon vs Irish whiskey]
Scotch can be matured in many types of wooden cask, and most scotch is matured in used bourbon barrels. If you hear the term ‘first-fill’ bourbon barrel when describing a scotch product, it means the unaged spirit was placed into a charred oak barrel used for the first time once the bourbon was disgorged.
Many other types of oak casks are used to mature and/or finish scotch, with names like sherry butt, hogshead, Madeira drum and puncheon. These represent Scottish distillers’ long history of buying casks on the secondary market to mature their spirit. This history goes back long before U.S. lawmakers required new American charred oak barrels for bourbon production — a law created after the repeal of Prohibition.
Bourbon can be matured for any amount of time, but to be considered a ‘straight bourbon,’ it must be matured in new charred American oak barrels for at least two years. All types of scotch must be matured for over three years according to U.K. regulation.
Both must be bottled at a minimum of 80-proof to be sold in the United States.
What is Scotch whisky?
Scotch whisky describes any type of whisky produced in Scotland. By law, it is a spirit produced from a wash of cereal grains fermented, distilled and matured in Scotland for over three years.
Wash is another term for mash, or beer, and is one of those European-specific terms that can trip up those new to the whisky category because they differ from the terms American distillers use. We’ll try to point those out as they come up.
Types of Scotch
There are three main types of scotch whisky. Let’s look at each one, so you know what to expect next time you order a scotch cocktail or dram (pour) of scotch at your favorite whiskey bar.
Single Malt Scotch
By law, single malt scotch must be produced from 100 percent malted barley and distilled using a traditional copper pot still. And it must be produced at one single distillery. These rules reflect a long history that goes back centuries, so single malt is considered the more traditional form of whisky produced in Scotland.
Barley is malted by soaking the grains to cause them to germinate and then quickly halting the process by drying them. This allows the enzyme-packed germ to be utilized during the fermentation process. Malted barley remains a vital ingredient because scotch production regulation prohibits the use of lab-produced enzymes.
Traditionally, each distillery would have a heated malting floor where the production crew would continually rake the grains to ensure they dried evenly. Today, many producers use mass-produced malted barley, but the tradition is coming back as producers and customers learn to value locally sourced ingredients.
There are five scotch whiskey regions: Islay, Speyside, Campbeltown, the Highlands and the Lowlands. Each region has its specific, nuanced flavor profile. As you continue your journey in scotch, you may be able to taste the traditional production techniques and influences of climate that make each unique.
One example is from the Isle of Islay. Due to a lack of trees, this Scottish island is known for using peat to dry the malted barley. When people describe scotch as ‘smokey,’ they often refer to the influence of peat smoke, which has a significant impact on the final taste profile.
Blended scotch describes a whiskey type that blends single malt whisky with whiskies made from various grains using a column still.
The column still was an invention in the 1800s, and the resulting blended whisky represents a relatively modern approach to scotch. After the invention of the Coffey still in 1830, the production of whisky increased dramatically. By using steam-powered column distillation, whisky makers could produce larger volumes using less energy in only one pass. Advances in chemistry meant they could also create wort (filtered beer) out of other grains — including wheat and maize (corn). The result was a whisky product that could be offered for a much lower cost.
Column-distilled whisky made from wheat or corn was much different in terms of taste. It has a much lighter and mellower profile than its single malt forebearer, with flavors reflecting the delicate sweetness of corn or the soft round character of wheat at a higher proof off the column.
Merchants soon found value in blending these less expensive, milder column-distilled whiskies with the more expensive, flavorful malt whiskies from the hundreds of distilleries throughout Scotland.
Shopkeepers like John Walker, John Dewar and William Teacher all created their own unique blends to entice customers to their stores during the early 1800s. Today, their names represent some of the most well-known scotch brands in the world.
Blended Malt Scotch
Blending single malts from different distilleries is a practice that has a long tradition in Scotland.
These products are sometimes referred to as ‘vatted’ whisky, the legal name for the category before legislation was updated in 2009. It describes the act of dumping barrels produced at different distilleries together into a large wooden vat in order to marry the flavors before bottling.
Well-known international brands include Peat Monster, Monkey Shoulder and Johnnie Walker Green Label. There are various clubs — most based in the U.K. — that offer exclusive vatted releases to their members.
What is Bourbon whiskey?
By law, bourbon must be: made in the United States, contain at least 51 percent corn in the mash bill — or grain mixture — and be matured in new American charred oak barrels.
Unlike Scotch whiskies, malted barley often takes a back seat to corn, rye, and even wheat grains in bourbon making. Although a portion of malted barley — anywhere from 5 to 25 percent — is still used by most distilleries by tradition, bourbon doesn’t need to contain any barley. And because the use of lab-produced enzyme additions is not prohibited like they are in Scotland, it is possible to convert grain starch into sugar without malted barley. Craft brands have released bourbon products with zero malt content.
Types of Bourbon
By law, bourbon must be made with at least 51 percent corn.
We mentioned most distillers use a proportion of malted barley out of a sense of tradition — and to take advantage of the flavor it adds to the finished spirit. The choices in grain proportions have a significant impact on flavor. Most whiskeys round out the grain ingredients with rye and wheat.
Most — but not all.
Today, distillers large and small are breaking the mold to experiment with non-traditional grains to explore new flavors and create new types of whiskey that fall under the broader bourbon category.
The designations below — traditional, high rye, wheated and non-traditional — are not legal designations, but rather bourbon styles that help describe nuanced approaches each distiller considers when making whiskey.
Bourbon must have at least 51 percent corn, but most bourbon producers use much more — about 75 percent. The impact of more corn creates a sweeter taste in the finished product.
Many bourbons with a bold, spicy flavor are described as high-rye bourbon. To accomplish this, the whiskey maker adds a higher percentage of rye as the primary flavoring grain after corn.
These bourbons shouldn’t be confused with rye whiskey — which is a separate sub-category among American whiskeys that requires the product to contain at least 51 percent rye grain in the mash bill.
Wheated bourbons describe whiskeys that contain wheat as the flavoring grain. The resulting product has a smoother, mellower rounded flavor profile by using wheat instead of spicy rye.
Today, the influence of the Craft spirits movement has led to innovation among the bourbon sub-category.
Producers are now experimenting with non-traditional grains like quinoa, buckwheat, and oats as flavoring grain. While corn remains the primary ingredient, by adding complexity to their mixture of grains they can add new notes while maintaining bourbon’s traditional sweet corn flavor profile.