Side by side: Glenfiddich 12yo, 15yo & 18yo

Looking at three different drams from the @GlenfiddichSMW distillery aged range, the 12yo, 15yo and 18yo - what differences are there?

Dram	12yo	15yo	18yo
Characteristics	40% ABV, Coloured, Chillfiltered	40% ABV, Coloured, Chillfiltered	40% ABV, Coloured, Chillfiltered
Distillery info	Flowing in the Valley of the Deer since 1887, our family’s signature expression is the world’s most awarded single malt Scotch whisky. With a unique freshness from the same Highland spring water we’ve used since 1887, its distinctive fruitiness comes from the high cut point William Grant always insisted upon. Carefully matured in the finest American oak and European oak sherry casks for at least 12 years, it is mellowed in oak marrying tuns to create its sweet and subtle oak flavours. Creamy with a long, smooth and mellow finish. Nose: Some people say they are reminded of a sweet shop, others can smell an orchard in bloom a distinctive pear aroma. Taste: Fresh fruit, quite sweet, with a rewarding hint of vanilla sweetness. Finish: Long, warming and sweet.	Our 15 Year Old expression is created using a technique pioneered by our Malt Master and it's warm, spicy flavours are transformed with the alchemy of the Solera Vat. Aged in European oak sherry casks and new oak casks, the whisky is mellowed in our unique Solera Vat, a large oak tun inspired by the sherry bodegas of Spain and Portugal. Never emptied, and kept half full of whiskies since 1998, our Solera Vat is the culmination of curious minds and the pioneering spirit of our family. Nose: An intriguingly complex aroma. Sweet heather honey and vanilla fudge combined with rich dark fruits. Taste: Silky smooth, revealing layers of sherry oak, marzipan, cinnamon and ginger. Full-bodied and bursting with flavour. Finish: Satisfyingly rich with lingering sweetness.	We use fine Spanish Oloroso wood and American oak to mature this rich, intriguingly fruity and robust oak expression, but there are many more reasons why this expression is special. Every batch is individually numbered and carefully watched over. Each has extraordinary consistency and character from an intense marrying period, and a warming, distinguished finish. Nose: A remarkably rich aroma with ripe orchard fruit, baked apple and robust oak. Taste: Richly delivers luxurious dried fruit, candy peel and dates. Overlaid with elegant oak notes. Finish: Warming, rewarding and distinguished.
My thoughts:
Appearance	All three are coloured to a lovely shade of gold then chillfiltered....
Nose	Very fresh on the nose -cut grass and orchard fruit - mainly pears but with a faint note of dry apricot too. Some orange notes develop after being in the glass a while.	Again very fresh on the nose - more cut grass and orchard fruit but with a sweeter edge - honey and banoffee notes - yummy!	A more robust nose - baked apple from the official notes in buckets. There's an oak spice and dark fruit note. Banoffee notes from the 15yo develop after a while.
Palate	Super smooth arrival, sweet with honey and pear notes. A little spice on the tongue, slightly drying with a small sour note.	Again super smooth but slightly thicker, orchard fruit and strawberries. Not as sweet and with more of a spicy kick on this one - orange oil and ginger notes.	Again super smooth, slightly thicker again - almost syrupy but without excessive sweetness. Very drying with oak notes - hardly any spice. After a few sips milk chocolate notes develop.
Finish	Short and spicy - loads of ginger and chilli, warming and slightly drying.	Again fairly short, warming, slightly sour. There's the fruit from the nose and palate and a lovely honey note.	Slightly longer  than the previous two, oak dominates with a little spice and a slightly sour grapefruit note. There's a lingering chocolate note drying the mouth.
Overall	I was given a bottle of the 18yo as a leaving present from my last job and it didn't last very long - a lovely dram, as are the 15yo and 12yo. There's two big question for me : why are they all coloured and chillfiltered and why only 40% ABV? Yes I understand they produce millions of bottles and they want them all to be the same but I'm sure after 12, 15 or 18 years in a cask, a little blending would solve that issue. Chill filtering is just silly - in my opinion it removes a layer of taste and 'thickness' to the dram - especially at higher ABVs, and for me that's the key point - why are they all diluted to 40%? I'm sure the 12yo would be better at 43%, the 15yo at 46% and, go on stretch it a bit, 48% or 50% for the 18yo. The 18yo is marketed as a special dram, but at 40% it just isn't. OK enough of my rantings, the 15yo is probably my pick of the three - some interesting banana / toffee / honey notes throughout which give it the edge, but it would be so much better at 46% or higher.