In the UK, “100 proof” signifies a spirit with 57.15% alcohol by volume, often rounded to 57.1% ABV. It also names an extensive, affordable series by independent bottler Signatory Vintage, with over 30 releases filled at 57.1% ABV (some of them being ‘Exceptional Casks‘). We are examining three early releases in this series: the Glentauchers, Glenrothes, and Caol Ila 100 Proof Signatory Vintage, specifically numbers 6, 8, and 10.
What Does 100 Proof Mean?
In the UK, “100 proof” denotes a spirit with 57.15% alcohol by volume (ABV). This system originated in the 18th century, when testers soaked gunpowder pellets with spirits and tried to ignite them. If the gunpowder ignited, the spirit was “overproof,” indicating high alcohol content. If it didn’t ignite, it was “underproof,” signifying low alcohol content. “100 proof” became the standard where gunpowder barely ignited, roughly 57.15% ABV. This test helped British sailors and merchants verify rum strength and detect dilution. Over time, improved distillation and measurement tools standardized “proof,” which remains in spirit labeling today.
In the U.S., “proof” differs. “100 proof” means a spirit has 50% ABV. This difference stems from varying standardization between the UK and U.S. The UK kept the traditional measure, while the U.S. adopted a system where proof is double the ABV percentage. Thus, a U.S. “100 proof” spirit is weaker than a UK “100 proof” spirit. Despite this, “proof” remains crucial for indicating alcohol content in both regions.
Glenrothes 2015 100 Proof Edition #6 Signatory Vintage Review
We begin with the 6th release in Signatory’s 100 Proof series: a Glenrothes distilled in 2015 and bottled on February 3, 2024. This single malt aged for 9 years in first-fill Oloroso Sherry casks before bottling at 57.1% ABV, with a probable slight reduction to reach this strength, and without added colouring or chill filtration. The release includes 3,988 bottles. It’s available for under €50 in Germany and slightly more elsewhere in Europe, though it seems sold out in the UK.
Colour:
Mahogany.
Nose:
Neat: Rich with typical Oloroso sherry notes, including dried fruits like figs and dates, leather, and nutty aromas of hazelnut and almonds. There’s also marzipan, orange peel, light oak, plum, cherry, and a hint of sweet and sour aroma.
With water: The nose becomes slightly sharper, with the sweet and sour aroma fading away. Overall, it feels simpler and less complex after reduction.
Palate:
Neat: Brown sugar, butterscotch, and toffee, with a touch of spice, including pepper, cinnamon, clove, and nutmeg. It has a good oily mouthfeel, complemented by vanilla and milk chocolate, with hints of dark cherries and dried figs.
With water: The butterscotch and brown sugar flavours are more pronounced, with a creamier mouthfeel. The spices feel slightly stronger, and there’s more oak presence. Herbaceous notes and a touch of mint also emerge.
Finish:
Warm with lingering spices and butterscotch, slightly drying, with a hint of oak and a good length.
Comments:
This is a very impressive and youthful Glenrothes. It’s a classic example of a first-fill Oloroso sherry cask, delivering exactly what you’d expect, and it’s well made. At €50 a bottle, it offers excellent value. It might be the first affordable Glenrothes I’ve truly enjoyed, though I admit my experience with the distillery’s offerings is somewhat limited.
Rating: 7/10
Glentauchers 2012 100 Proof Edition #8 Signatory Vintage Review
Next up is a Glentauchers distilled in 2012 and bottled at 100 proof by Signatory Vintage on February 1, 2024, as Edition #8 in the 100 Proof series. Matured in several first-fill Oloroso sherry butts, this release yielded 4,066 bottles, all without chill filtration or added coloring. While sold out in the UK, it’s available for under €50 in Germany and slightly more in countries like Belgium and the Netherlands.
Colour:
Tawny.
Nose:
Neat: The nose is somewhat reserved, with subtle aromas of dusty sultanas, with a fleeting citrus tartness. Notes of light caramel, mild spices like cinnamon and nutmeg, brown sugar, and a hint of herbs. A touch of green tea.
With water: More pronounced dusty notes and a slight mustiness, reminiscent of wet oak planks and walnuts.
Palate:
Neat: Initially sweet with peppered butterscotch. The mouthfeel is oily, with a delicate citrus note in the background. Flavours of walnuts and milky coffee emerge, followed by hints of freshly squeezed orange juice, dark cherries, black tea leaves, and dark chocolate after some aeration.
With water: Stronger caramel notes, with more pronounced pepper and alcohol heat. The mouthfeel becomes creamy and slightly drying.
Finish:
Medium-short, featuring chocolate and butterscotch, with lingering citrus and a touch of oak.
Comments:
This whisky is enjoyable, yet it feels somewhat reserved on both the nose and palate, as if holding back its full range of flavours and aromas. While pleasant, it leaves the impression that something is missing. The butterscotch note dominates the palate, overshadowing other flavours. Overall, it’s good, but there’s an elusive quality that seems to be absent.
Rating: 6.5/10
Caol Ila 2015 100 Proof Edition #10 Signatory Vintage Review
We wrap up with a 2015 Caol Ila, bottled on February 15, 2024, by Signatory Vintage as the 10th Release in their 100 Proof series. Matured for 8 years in first-fill Oloroso sherry butts and hogsheads, it was bottled at 57.1% ABV without chill filtration or added coloring. It’s available for under €50 in Germany, slightly above €50 elsewhere in Europe, and around £47 in the UK.
Colour:
Deep copper.
Nose:
Neat: Distinctly Islay with a maritime peat character. Prominent notes of crushed seashells, sea breeze, and seaweed, accompanied by a wet gaze and smoked bacon. The alcohol presence is more noticeable compared to previous bottlings. Lemon notes emerge subtly over time.
With water: The nose remains largely unchanged.
Palate:
Neat: Features sweet peat and medium smoke, with flavours of smoked bacon and fish, salted caramel, lemon juice, and peach-flavoured petit-suisse. Vanilla and honey are prominent, with hints of blackcurrant and blueberry jam.
With water: Initially sweeter, then the sweetness fades, giving way to more pepper and smoke. Notes of butterscotch, salted caramel, and a hint of peanut butter follow.
Finish:
The finish is characterised by ashy smoke, burnt wood, caramel, and traces of oak, with a medium length.
Comments:
This Caol Ila offers a robust profile with a caramel note that’s surprisingly prominent. Interestingly, the sherry casks seem to have had a subtle influence, not imparting as much additional flavor as one might expect. However, given the typically high quality of the distillate, this isn’t necessarily a drawback.
Rating: 7/10
Thanks Arnaud! Bottle pictures courtesy of Whiskybase.