Whisky talk

The ‘Sherry Bomb’ Whisky Arms Race – What are Distilleries Doing to Create These Sherry Monsters?

The world of single malt Scotch is a broad spectrum of colour, aroma, taste, history and geography – this is mainly due to the fact that unlike bourbon which has to be aged in virgin American oak, Scotch whisky can be aged in a vast array of different cask types, including but not limited to sherry cask (Oloroso, Pedro Ximenez, Fino, etc), virgin oak, bourbon cask, port tube, Sauternes cask, wine cask…the list goes on.

There are any number of choices that can be used to age our favourite spirit, the possibilities are endless, take the Amrut Spectrum for instance where they had a cooper make a cask from various different staves from five different wood types such as ex-bourbon, ex-sherry, virgin oak and so on.

In the 19th and 20th century, blends were favoured over single malts; this was due to the fact that distilleries often produced pretty harsh, unpalatable distillate – this is when the blenders stepped in to balance the flavours, ultimately making the whisky more palatable and contributing a great deal to the growth of the Scotch whisky market.  Blends still make up the vast majority of the global market for Scotch whisky, but it is the single malt whiskies that are considered the cream of the crop by whisky connoisseurs and enthusiasts – single malt whiskies provide a more intrinsic experience; they are linked to one specific place, one specific time in history, you could even find out who distilled the particular dram you’re drinking if you really wanted to.  I think it was the late 90’s when we really saw the emergence of peated whiskies which mainly come from Islay but other distilleries do produce peated malt such as Highland Park and Benriach.  This love of peat seemed to grow and grow to the point some people won’t let anything else pass their lips, it has created what can only be described as a peatphile cult.

Malting floors at Laphroaig on Islay.  Laphroaig are known for their very peaty whisky.

Moving on from peated whiskies which are still very popular and in high demand but I believe we have recently entered the age of the sherry bomb, this is a term I hadn’t even heard until the past couple of years.  While there are popular distilleries that have a heavy sherry influence that have been around for a long time such as Glenfarclas and Bunnahabhain, I believe the ground zero of the sherry bomb love affair started with Glendronach, a distillery which has recently made a resurgence after being acquired by Benriach, prior to this it had been owned by Teachers and Chivas Brothers.  The backbone of Glendronach is sherry cask whiskies and they produce some amazing heavily sherried whisky.  The new rebranded bottles of Glendronach only started to come out around 2008, the 15 year old ‘Revival’ was a huge hit, it remains one of my favourite whiskies, you can read my review of this whisky here.  Anyway, over the past few years people have really been fussing over Glendronach and so they should be, and in my opinion it is Glendronach who have introduced the ‘Sherry Bomb’ to the masses, sure these whiskies existed beforehand but they were more of a rarity, destined for independent bottlers or rare old single cask distillery bottlings that were out of the price range of most people.  Glendronach released whiskies that were fully aged in Oloroso or PX casks for the full term and could be had for as low as £40.


There is something alluring about sherry bomb whiskies, they’re tantalisingly dark – you can almost smell and taste it through the bottle, the long slow legs that are produced with every swirl, the sharp lingering necklace that sits around the inside of the glass and refuses to leave; and this is all before you’ve even brought the glass to your nose.  These whiskies can be hit or miss, you can get what’s called a ‘sherry flat’, this is where the flavour of the sherry is so dominant it kills the character of the spirit, if the cask is fresh and too ‘wet’ (too much of the previous liquid remaining) you often get no oak influence, however, when a distiller or bottler gets it right these whiskies generally have a robust and complex palate – the flavours you can expect are of chocolate, coffee, caramelised pecans, butterscotch, juicy raisins and sultanas, sticky dates, toffee, rich fruit cake, sweet spice and fresh cream.

At the higher end of the sherry bomb spectrum you will find single cask Karuizawa whiskies from Japan, these whiskies will be out of the price range of most single malt drinkers with the cheaper bottles coming in at around £1,000 and for the more expensive bottles which are up to 50 years old you can expect to pay up to £20,000 – these whiskies are often almost black in colour due to spending many years in first fill sherry casks.  A couple of years ago Jim Murray named the Suntory Yamazaki Sherry Cask as the world’s best whisky and as per usual everyone shit their pants, ran to the nearest place they could get a bottle and just like that the whisky disappeared from shelves all over the world and this £200 whisky now commands a price of around £1,500.

Karuizawa whisky of various ages, notice the almost black colour of the heavily sherried pair on the right.

So, the point I am getting at is that there have been a few events (I have only mentioned a couple) that have created a unstoppable desire in the whisky drinker to encourage these luxuriously dark sherry monsters out of their caves.  If you think I am over exaggerating, there has even been a new independent bottler emerge called ‘Darkness’ who specialise in heavily sherry influenced whiskies.  What we’re now seeing is a race of who can create the stickiest, darkest, sweetest and richest sherry cask whisky.

So, this race that may or may not be taking place, it could just be a figment of my imagination manifested in late night ramblings…is it a good thing? Well, yes, I think so, I love sherried whiskies, provided they are done right, I love the Glendronach 15, the Bunnahabhain 12, the Glenfarclas 15 and a never ending list of others including many independent single cask bottles.  We should enjoy the age of the sherry bomb, but we should be curious as to what we’re drinking and whether the appearance and taste of the whisky is deceiving us, and I’ll now go through some of the reasons why we should exercise caution.

  1.  E150a (oh no, e numbers) – forget most of what your mother told you about e-numbers, they’re more often than not perfectly fine to consume, take E150a for instance.  E150a is sugar that has been heated to just before the point of it being destroyed, what it produces is a very dark black syrup.  A small amount of E150a added to whisky can significantly change the colour of a whisky…so that mahogany coloured dram you’re swirling around your glass thinking “damn, this must have been in a first fill Oloroso cask for quite some time” could have been in a second fill bourbon cask for 3 years, finished in a sherry cask for a few months and then had a bit of E150a chucked in to make it appear like a longer aged spirit.
  2. Wet casks.  Scotch whisky is not supposed to have anything else added to it, however distillers can get away with a certain amount of ‘residue’ being left in the cask before they fill it, this residue could be sherry, port, wine, bourbon or whatever.  I can’t imaging anybody checking how much residue is left in the casks.  If you imagine having even a few hundred millilitres of a dark and sweet sherry like Pedro Ximenez or Oloroso mixed in with the whisky, that will alter the colour and it will alter the taste of the end product.

What has spurred this post on was a observation made by a man called Andrej.  The observation was posted into the Facebook group ‘Malt Maniacs and Friends’, a group I am part of.  He pointed out that when spirits are sold in Finland, they are fist analysed by an independent laboratory, two of the tests they do are for total extract and total sugar.  Naturally, distillate should not contain any sugar as sugars are non-volatile compounds that do not evaporate and thus will not make it to the neck of the still and into the condenser.  For most whiskies there will still be a small amount of sugar in the whisky, this usually equates to around 1g/L, you might be asking yourself where this sugar comes from if it doesn’t come from the spirit?  The sugar comes from the cask, if a cask has previously held wine, sherry, port or something similar with a high sugar content then some of this sugar will remain in the cask, thus adding sugar to the whisky that fills it.  What Andrej noticed was that on the Finish alcohol website ‘Alko’ the data provided for the Ardbeg Dark Cove showed that it contained 5g/L total extract and 4g/L total sugar, you can see this here.  Now, 4g/L is a lot of sugar – sugar which certainly isn’t coming from the distillate, the only sugar generally found in the wood of casks is cellulose which is insoluble in alcohol and I very much doubt they would include this in their sugar analysis.  The only logical explanation is that the sugar has come from whatever was previously in the casks, in this case it would be sherry and considering how dark this whisky is (even Ardbeg sell it as “The darkest Ardbeg ever”) we’re going to presume that the casks previously contained the darkest and sweetest sherry of them all, Pedro Ximenez.

Another commenter, Sihan Zheng stated that a typical Pedro Ximenez sherry contains around 300g of sugar per litre (I wasn’t joking when I said it was sweet, it also goes well over ice cream), back to the maths…300g/L equates to 0.3g/mL, since the Dark Cove is a naturally coloured whisky there should be no E150a contributing to the sugar content, so all of the sugar must be coming from the residual sherry which would mean that to achieve a sugar content of 4g/L there must be at least 13 mL of sherry going into every litre of whisky, even if say you assumed that 1g/L of the sugar content came from another source that would still mean that 10 mL of sherry would be in the whisky to.  Now, I might point out that all of this is based on the information I have read and have no idea on how Ardbeg make this particular whisky, but even if say the whisky was finished in small PX casks around 200 litres in volume, for 13 mL of sherry to make up each litre that would mean that the cask would have to contain 2600 mL of sherry, now I am not to sure on the rules but I would imagine that would not be classed as ‘residue’, so this begs the question, where is all of that sugar coming from?  My guess is that maybe some PX sherry is left in open casks where the water and alcohol can evaporate, this would heave behind what would essentially be a PX concentrate before being filled with the whisky – I can’t think of any other viable option.

If you have any questions or more importantly answers 😉 don’t hesitate to drop me a message, cheers.




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