Have you ever wondered where the term ‘alcohol proof’ came from or what ‘100 proof’ means or why 100 proof in the UK is different to 100 proof in the US? Well, wonder no more.

The term ‘alcohol proof’ was first coined in 16th century England and refers to a test to demonstrate the potency of an alcoholic spirit. Historical accounts of the test vary and it quite possibly could have been conducted using a number of methods, all with similar base principles. That said, there are many false truths regarding the origin and intent of this test in circulation and it took some investigating to separate myth and legend from credible facts.

An alcoholic spirit at its most basic is a solution, a mixture primarily of alcohol (ethanol) and water. Alcohol is more volatile than water and alcohol vapour will ignite if exposed to a naked flame. Water will not, so as you increase the ratio of water to alcohol in a spirit, it will eventually reach a point where the spirit will no longer produce enough flammable vapour to ignite.

So, if you want to test the potency of an alcoholic spirit, why not simply try to set it alight? Good question.

Most people will tell you the alcohol proof test was conducted by mixing a small amount of the spirit to be tested, with a quantity of gunpowder before attempting to set it alight; but why use gunpowder at all?

The term ‘keeping your powder dry’ reputedly originated in an account of Oliver Cromwell during his Irish campaign in the mid-17th century, in which he instructed his troops to ‘put your trust in God; but mind to keep your powder dry’. However, the term was no doubt in common use far earlier by soldiers and sailors employing gunpowder-based weapons from at least the 12th century.

Gunpowder is hygroscopic, meaning it tends to absorb water and when damp will not ignite. The reason for this is the main ingredient of gunpowder, potassium nitrate, is soluble in water. Put simply, this means that if exposed to enough water, the potassium nitrate in gunpowder will dissolve, removing it from its delicate arrangement with the carbon and sulphur, making the gunpowder harder or impossible to ignite.

Some commentators claim that high strength spirts were required for naval operations due to their storage in close proximity to the ships gunpowder supplies.

The high alcohol or overproof strength would ensure that if the rum or gin splashed on or mixed with the gunpowder, the powder would still work. This suggestion is complete nonsense.

Gunpowder and ammunition was stored on board ships in the ship’s magazine, much like explosive ordnance still is on today’s warships. Any other hazardous materials are segregated from the magazine to minimise the chance of accidents or catastrophic events. All attempts were made to keep gunpowder dry on a ship, ensuring it was only exposed to the elements immediately prior to use. In fact great care was taken to protect the magazine from enemy fire, vermin and stray sparks or embers. It is ludicrous to suggest that a sailor’s grog had to be kept at high strength just in case it spilt on the gunpowder it was supposedly stored with.

I have read many accounts of the origin of alcohol proof, complete with some rather tenuous reasons why things occurred. What was the purpose of this test in the first place?

In the British Empire, distilled spirits, often rum, was used as a form of currency where traditional notes and coins were in short supply. If you were a sailor being paid in rum, you would want to know your payment was to a certain standard and not watered down would you not? If that was the case, then I can understand why a test was developed.

Additionally, if this was the initial purpose of the test it may explain why gunpowder was used rather than just setting the spirt alight? Theatrics. It is a far more satisfying conclusion for a sample to burst into flame and smoke with a bang, rather than to burn silently with a barely visible flame. Perhaps quite a show was made of proving the strength of the rum ration? Or perhaps the test was just a means to part young and impressionable powder monkeys from their rum ration, rather than something conducted routinely on the ship?

The alcohol proof test is commonly agreed to have consisted of mixing an alcoholic spirit with gunpowder and then attempting to ignite it.

If the water content of the spirit was too high, the gunpowder would be left too damp to combust, once the alcohol fumes had burnt off. This was not the most scientific of tests since external factors such as temperature, the ratio of gunpowder to liquid or the time waited after soaking before igniting would affect the results. But if the intent of the test was to make a show, science had little to do with it.

At the end of the 17th century, the British Empire regulated distilling, simultaneously encouraging the distillation of alcohol and imposing a tax on it. 

This relationship between gunpowder and rum probably explains why gunpowder became an intrinsic part of the alcohol proof test, at least within the British Navy. It would also make a convincing story of where the term ‘Navy proof’ comes from when describing a particularly potent alcoholic spirit. Unfortunately, that is also a fallacy. The term ‘Navy proof’ was first used in the early nineties - nineteen nineties - by an astute advertising department for a popular gin brand.

At the end of the 17th century, the British Empire regulated distilling, simultaneously encouraging the distillation of alcohol and imposing a tax on it. The tax was introduced as a way of controlling the production and sale of alcohol, curbing over intoxication, drunken behaviour and crime and last but not least, raising government revenue. Alcohol content was of little concern to the tax man at first, with gin being taxed at a lower rate than strong beer, until the introduction of the disastrous Gin Act 1736 and the more successful Gin Act 1751.

Some suggestions have been made that the alcohol proof test was used for tax collection purposes prior to the 17th century.

I could not find any evidence to support such claims. Although it does present a nice setup and believable reason why the test was invented; who doesn’t want to believe it was concocted by the government of the day so that they could tax the working man at a higher rate? Although it is believed the alcohol proof test originated in the 16th century, it is likely the practice became more common after regulated alcohol taxation was introduced and prior to more scientific means to test alcohol content were developed.

The alcohol proof test was used to determine if the alcohol contained within the tested spirt was above a certain concentration, rather than to gage the exact strength of the spirit. The numeral 100 in the term ‘100 proof’ appears to be an arbitrary figure used to denote the transition point between being under or overproof and was used for no other reason than as an easy way to communicate a greater or lesser alcoholic strength from the standard.

In the UK, the proof system for testing alcohol content was eventually replaced by measuring specific gravity, with a standard being agreed upon in 1816. By comparing the density of an alcoholic spirit with that of distilled water at the same pressure and temperature, is possible to accurately measure a spirit’s alcohol content. A spirit at 100 proof was measured to be approximately 57.1% alcohol by volume or ABV.

In 1824 the French chemist, Joseph-Louis Gay-Lussac proposed a sensible proof scale based on ABV, where pure water was considered ‘0 proof’ and pure alcohol or 100% ABV was considered ‘100 proof’.

In 1848 the United States of America introduced its own alcohol proof system where 100 proof was defined as 50% ABV. Why? I have no idea. Perhaps because larger numbers are more attractive to consumers, so marketing something as 80 proof (40% ABV by the US scale) is more desirable than the same product labelled as 40 proof?

So there you have it, the explosive origin of the alcohol proof system.

Did you learn something from this article or do you think I’m wrong? Please let me know in the comments and I will produce more content like it in the future.
- Whisky Dad

Distillery: Westland, Seattle, USA

Name: American Oak

Make: American Single Malt Whiskey

Extra Info: Westland whiskey is made with five different malts: Washington Select Pale Malt, Munich Malt, Extra Special Malt, Pale Chocolate Malt and Brown Malt. The peated expression is made with six malts since an additional peated malt from Scotland is used to introduce the smoky character.

Westland whiskey had been on my radar for a while because they produce an American whiskey but not a bourbon or rye. I was lucky enough to attend a local tasting event and got to try the three standard Westland expressions and walked away with a bottle of the American Oak.

Presentation: I absolutely love the Westland label; a diamond shape that mirrors the distillery logo set in front of the four corners of a rectangle displaying map imagery with topographical lines that mimic the grain of milled wood. I also love the colour scheme and the heavy based bottle. I would go as far as saying it is one of my favourite designs to date. One thing I was disappointed with however was the inclusion of a plastic screw-top lid rather than a cork stopper. I know it may seem odd, but I enjoy hearing the pop of a cork when I open my whisky and feel a screw-top cheapens the product. Bottled at 46% ABV.

Appearance: Non-chill filtered, dark gold in colour, with no additional colouring added; no mean feat considering it has only been aged for two and a half years. 

Aroma: Quite fragrant, somewhat floral, citrus notes and coffee beans.

Flavour: Velvety mouthfeel, a little spice, cherries.

Finish: Short, some lingering spice and mild warming.

No, nor would I buy the Peated or Sherry Matured expressions either. That is not to say that Westland is onto something special here, it is just a little too young in its current form. Age the same whiskey for a little longer and I think there is great potential once the wood has had more time to interact with the spirit. That said, the only real giveaway to the whiskey's young age is the very short and mild finish. The aromas and flavours are there, but in my opinion, this isn't as good as the Westland spirit could be. A decent whiskey that should mature into a great whiskey. Keep an eye on Westland.

Disclaimer: I do not claim to have the nose and palate of a Master Sommelier, however, I am working to train my senses to better identify whisky aromas and flavours. Consider all my whisky 'Impressions' to be a work in progress and I hope to come back to each of them in the future to see if I notice anything different. Most importantly, I'm not just throwing around random aromas, flavours and adjectives for the hell of it; I am trying really hard to critically describe each whisky I taste - WhiskyDad.

Distillery: Heaven Hill Distilleries, Inc., Kentucky, USA

Name: Rittenhouse Straight Rye

Make: 100% Rye Whisky Bottled-in-Bond

Extra Info: Bottled-In-Bond means that this whisky conforms with the US Bottled-in-Bond Act of 1897. To comply with the Act, whisky must be at least 4-years old, bottled at 100 Proof (50% ABV), have no additives other than pure water and be the product of a single distillery.

I bought this for two reasons, it's a 100% rye whiskey (although spelt without the 'e' just to be confusing) and it is bottled-in-bond.

Presentation: I feel the Rittenhouse Rye comes in about half way between a cool Wild West style and a more modern design. The bottle is a simple clear glass design with a plastic screw top. The label is red and black, diamond-shaped, with a prominent 'Bottled-in-Bond' statement at the base that is repeated on the neck seal.

Appearance: Dark amber with a red tinge.

Aroma: Fresh smelling, almost cooling on the nose like menthol, stone fruits, peach and apricot perhaps, oak.

Flavour: Light, some sweetness, quite smooth, stone fruits, vanilla, pepper spice. Quite different to malt whisky, hard to describe.

Finish: Medium length, spicy, odd aftertaste.

Yes, rye whisky is quite popular at the moment but it is very different to malt whisky. I would like to come back to this some time after I have tried more rye whiskies and bourbons. This is quite an easy whisky to drink but it takes some getting used to. You may prefer to try it over ice or with a mixer. I still prefer a single malt scotch or good quality scotch blend but I think rye whisky is a taste I could learn to love in time.

Disclaimer: I do not claim to have the nose and palate of a Master Sommelier, however, I am working to train my senses to better identify whisky aromas and flavours. Consider all my whisky 'Impressions' to be a work in progress and I hope to come back to each of them in the future to see if I notice anything different. Most importantly, I'm not just throwing around random aromas, flavours and adjectives for the hell of it; I am trying really hard to critically describe each whisky I taste - WhiskyDad.

Distillery: George A. Dickel & Co., Tennessee, USA

Name: George Dickel No. 12 Tennessee Whisky (note no 'e')

Make: Tennessee Whiskey (note the 'e')

Extra Info: A Tennessee Whiskey is a Bourbon that has undergone the additional step of charcoal mellowing, or the 'Lincoln County process'. Traditionally, charcoal is made on-site by open-air burning stacks of sugar maple wood billets. The charcoal goes into a mellowing vat on top of a white wool blanket that filters out any particulate matter. Whiskey Trivia - George Dickel actually use two wool blankets, one on the top and one on the bottom.

Why did I buy it?

I bought this because it is a Tennessee Whiskey and not Jack Daniels. I have nothing against Jack Daniels, I just wanted to try the other Tennessee Whiskey.

Presentation: The bottle has a long neck, almost half the height of the squat bottle. It is made from clear glass with 'George Dickel' embossed on the shoulder. I love the label on this bottle; it looks like something straight out of the Wild West. Very cool. The whiskey has no age statement but it is claimed to be aged 'years longer' than George Dickel No. 8. Importantly, the '12' in the name does not mean it has been aged for 12 years.

Appearance: Dark golden orange in colour. There is no indication of e150 caramel colouring being added, but it does say 'chill-filtered' on the label; so is Jack Daniels.

Aroma: Sweet, lots of vanilla and a bit of caramel. Hint of spice.

Flavour: Smooth and sweet with a sudden hit of spice on the top of the mouth. Flavours of vanilla and oak spice. No smoke, but kind of a sweet burnt caramel in there somewhere. Most people would probably drink this with a mixer or on ice (which is fine) but that will change what it tastes like obviously. Personally, I usually drink this straight over ice. 

Finish: Very long bourbon aftertaste, with fading spice.

Yes, I love drinking this over ice on a hot evening or as a Highball (with soda water). I think it both smells and tastes great. If you are a Jack Daniels drinker but have never tried George Dickel, I would add this to the top of your wish list. I am very keen to try the other expressions in the George Dickel range.

Disclaimer: I do not claim to have the nose and palate of a Master Sommelier, however, I am working to train my senses to better identify whisky aromas and flavours. Consider all my whisky 'Impressions' to be a work in progress and I hope to come back to each of them in the future to see if I notice anything different. Most importantly, I'm not just throwing around random aromas, flavours and adjectives for the hell of it; I am trying really hard to critically describe each whisky I taste - WhiskyDad.