G&M Connoisseur’s Choice | 60.3% ABV

What makes a cask “good”?

As even the worms hiding deep under rocks must know by now, whisky is in a boom right now.

One hell of a boom in fact, which has given rise to unprecedented prices, the strangest of “investment” economies, and an altogether unrivalled amount of liquid on the market.

The benefit of this is that customers have never had so much choice. The naturally attached inverse of this is that choosing “good” whisky is precipitously difficult by matter of dilution, especially when that dilution is considered as a function of value. What was once merely very expensive is now completely out of reach. As a higher proportion of releases drift into this insulting space, we must be particularly selective about what we choose to buy and why we buy it.

There are more opinions floating around than ever before to help us save or spend our money which I think is overall a positive, especially since the majority are probably altruistic. The limiting factor in most of these helpful opinions, however, is they don’t have your palate and your preferences. We can always hunt for opinions and tastes that generally align with ours, but there are only so many palates we can trust that can taste so much whisky.

Stalwarts such as Serge Valentin of Whiskyfun have done a huge amount of heavy lifting, giving as consistent a palate and opinion as could be asked, to date reviewing about 18,000 whiskies and more than 22,000 spirits in total with the help of Angus. Even if we don’t have Serge’s preferences, by reading enough of his notes and understanding how he feels about whisky we’ve tasted, we can get a pretty good gauge for what the whisky will be like - think of it a bit like relative pitch. There was a time where Serge would have tasted a good proportion of what was hitting the market, whereas nowadays it’s really the smallest of fractions. As such, with the number of products hitting the market increasing, our capacity to find well-trusted sources giving some relatable indication on these products must decrease. The more the industry thrives, the less idea we have of where our palates sit in it. 

It’s not all doom and gloom - the influx of bloggers, podcasts, YouTube channels and websites that have sprung up on the topic of whisky has filled many of the spaces left in this expansion. Not just with opinions, but varying degrees of education so consumers might better arm themselves in making good purchasing decisions for their own palates. As I’ve touched on previously, if we can’t find a review for a whisky, we can at least look at a number of input parameters to increase the chances we will find whisky that gives us value.

The obvious ones like the ABCDs are almost a catch cry for whisky enthusiasm these days. But the more detailed the data we input, the better we can narrow and refine our parameters for enjoyment: Which distillery? Which vintage and era of production? (ie Benrinnes pre-post partial triple distillation). Which casks with which previous treatment? There are a plethora of variables we can feed in to determine how much we are likely to enjoy a product. This doesn’t always work of course, but like most things in statistics, it’s about a broader view; in this case, risk mitigation.

A prerequisite for this process, however, is access to good data and a knowledge base which supports its handling. In most of my reviews on Dramface, I’ve endeavoured to supply some pitifully small amount of both - my focus being less about the product being reviewed and more to do with giving a point of reference or example for some greater mechanism, whether it be fermentation, distillation or some other production variable. This time around, I think we should have a chat about casks: How do they make a difference? How much do they matter? And what should you be looking for depending on one’s palate and preferences?

First, let’s tackle the well debated issue of overall cask impact. Depending on who you listen to, figures typically between 60-80% tend to get thrown around abstractly as representing a whisky’s final flavour. The independent bottlers and cask brokers tend to err higher, the distilleries lower. This is, of course, utter drivel without a heaping mound of contextualisation. How old is the whisky? How large was the cask? What did the cask previously hold? What climate has the maturation occurred in? How was the cask coopered and possibly re-coopered? What kind of oak is the cask made of? You see where I’m heading. Consider for instance Lagavulin 8yo against any slew of fortified monsters - in this instance let’s pick on something like a Glendronach 1993 vintage sherry cask. 

Aside from the nonsensical whimsy of these quoted figures, we generally don’t get even the simplest of bloody metrics; 60-80% of what? Total molecules in solution? OAV or taste threshold? Total perceived sensory experience as a function of variety and or intensity? The barest minimum we ask from a measurement is some unit - I don’t feel this is an insurmountable request. No, these figures are tossed around in the same manner as the majority of other poppycock we the loyal consumer must endure with gritted teeth - marketing dribble. Folks that wouldn’t know a mash tun from a still that are probably paid more than most of the hard-working folk actually making our amber nectar, and thus increasing the price we pay for our bottles without actually contributing a damn thing to it. 

*Whew*

Alright, that’s a rant for another day, but believe me we’ll come to that in the fruition of time. The point is that yes, casks are drastically important. Anyone that’s tasted-new make knows it certainly isn’t whisky. But it’s a deeper, more meaningful consideration than a one-stop-shop percentage. Let us think about this properly. 

This poses a follow up inquiry: How do they make a difference? Well the usual and perfectly good answer to this is that there are generally three ways casks impart flavour; subtraction, addition and interaction. 

Let’s consider subtraction. There are a number of chemicals which the charred layer on the inside of a cask can bind with. Certain volatile sulphur compounds (such as dimethyl sulphide and dimethyl disulfide) are among those which see the most sorption with oak, particularly when the oak is charred such as in bourbon casks. Other losses of volatile compounds happen via oxidation reactions through cask breathing and vapour head space in cask. Certain undesirable compounds like methionyl acetate are among these. 

The additive component is probably the largest factor - ignoring any contributions from the previous cask contents, there are a slew of compounds. The tricky part is separating strictly additive from interactive. Certain phenols are created and added in the greatest abundance directly from the charring of casks, whereas other compounds are imparted by oxidation of hydrolysis or ethanolysis products from water-ethanol mixtures interacting with the lignins and cellulose/hemicellulose in oak. These include vanillin (derived from coniferyl alcohol oxidising to coniferaldehyde and then further oxidising to vanillin) and syringaldehyde (derived from sinapic alcohol oxidising to sinapaldehyde, further oxidising to syringaldehyde). 

Some of the most idiosyncratic compounds are furanones and lactones, particularly gamma-lactones which include cis-β-methyl-γ-octalactone, or more colloquially, whisky/oak lactone, known for its coconut, woody and oak-synonymous aroma. Other flavour active compounds include furfural and other carbonyls, hydrolysable tannins and their subsequent ellagitannins and saccharides, phenols and phenolic acids. There are certainly other compounds covered below or that are not yet identified by GCMS/HPLC, however their sensory significance will require extensive testing by isolation and organoleptic exposure in the standard manner. 

So now that we have some idea of what oak can do, we should look at the impact that oak selection,  seasoning and coopering has on these flavour contributions. The species of oak has importance- for instance, American oak is higher in the cis isomer of whisky lactone which has a higher pungency than the trans isomer, hence American oak tends to have higher association with coconut type aromas. Also, European oaks (particularly French) generally have higher lignin contents. 

Another important selection media for producers is the conditioning of the oak, namely air drying vs kiln drying prior to coopering. To simplify this explanation somewhat, I have included tables from Whisky Science, A Condensed Distillation to help demonstrate:

NOTE- The common exception for European oak charing is the increasingly popular STR casks, which in their original use by Dr Jim Swan (predominantly for Portuguese and then wider European wine casks) were never charred in the first place, hence “Re-char” is a bit of a misnomer. STR casks are more complex, however, since the partial purpose for toasting these casks which contain residual wine/fortified in the oak staves is to caramelise sugar components whilst retaining some of the wines’ aromatic properties. I have been unable to find good data on this particular mechanism which indicates a certain degree of speculation on this latter mechanism.

As we can see from the above data, the majority of tested chemicals are optimised by some degree of air drying. Compounding this, Martinez et al also found that air drying reduces non-hydrolysable oak tannins by a factor of two or more (tannin type and oak species depending) compared to kilning, reducing the astringent component of oak maturation.

There are two key suggested mechanisms for these differences in air dried samples. First, rain is suspected to extract phenolics including polyphenols (tannins) over long periods of time. Second, mould, fungi and potentially other microflora secrete enzymes which break down tannins and cellulose, as well as hydrolyse glucosides and thus reduce oak derived bitterness. The general consensus then is that air drying substantially modifies levels of oak flavour extractives and increases the desirable flavour impact of oak. 

Of course two of the largest variables for oak flavour contributions are toasting and charring. To be semantic, toasting is the intense heating (surface temperatures around 150-210⁰C) of wood material without combustion, whereas charring is the much higher temperature pyrolysis of the wood. Generally, only American oak used for bourbon, rye and a handful of other American spirits is charred, usually without toasting first, whereas most European oak casks used for wine and fortifieds are only toasted. It should be noted that charring without seasoning or toasting has been associated to varying degrees with an unpleasant “sawdust” character probably indicative of E-(2)-nonenal (cardboard/papery flavours in beer) and other medium-long chain carbonyls with similar organoleptic descriptors. Lab studies emulating oak toasting above 200⁰C have been shown to reduce these undesirable compounds to trivial levels in short time periods as shown below. This goes a long way to explain the characteristic wood shaving/sawdust note commonly found in bourbon. The variation in this data for the coopered oak samples in the table below is likely indicative that time of toasting, temperature or both were insufficient to replicate lab data.

Aside from this, toasting creates an abundance of desirable compounds for whisky including furfural (biscuity, almond), cyclotene (caramel, maple, liquorice), maltol (sweet, caramel, malty) and for heavy toasting, megastigmatrienones (tobacco, incense).

Charring contributes some of the most commonly associated flavours of oak such as vanillin and 4-vinyl-guaiacol (clove/spice) and other compounds as shown in the table below. The ratio of syringyl to guaiacyl components of pyrolysis is a monotonically decreasing function of temperature between ranges of 300-600⁰C, so maximal variety of flavours from charring indicates a moderate approach. Additionally, high degrees of charring can thermolytically decompose or volatilise compounds made during toasting, so the interplay becomes further complex.

Of course most of the single malts we’re enjoying aren’t coming directly from newly coopered casks, rather from ex-bourbon barrels or refill casks of another nature. While I’ve touched on some of the flavour contributions we might expect to see from previous wine cask fills in my Trippy Tagine article, we have some indication for the more significant oak contributions of new vs. refill casks given below.

The size of casks also plays a number of roles. As explored in my Midnight Foxtrot review, the degree of previous cask fill influence has a strong correlation to cask size. Other mechanisms to consider include the rate of extraction from cask material vs the rate of interactive and oxidative processes. The ability for a whisky to become mature through complex reaction mechanisms like oxidative pH reduction, Le Chatalier transesterification and volatile off-gassing is limited by time during which extraction processes simultaneously occur. There is a risk of so-called “over-oaking” if these slow tertiary processes are outstripped by cask extraction. 

So how is this helpful to you and I, the consumer at the end of the line? Well, again, the better armed we are with information the better buying decisions we can make for our palates. If one desires a sweet vanilla and clove baking spice bomb, then a heavy char virgin American oak cask will probably suit. However, if one desires a complex lactone driven oak profile low in overtly sweet spectrum flavours, then a heavily toasted French oak cask from a cooperage renowned for long air seasoning is probably the better choice. I’m oversimplifying this, but essentially what I mean is use good data and do your research.

Review

Gordon & MacPhail, Connoisseur’s Choice, Highland Park, 2006, Cask #4268, 60.3% ABV
AUD$240 (paid $170) sold out

I have a long-standing love of Highland Park. Many of the official bottlings have been somewhat disappointing, and I think principally this comes down to the distillery’s choice of oak and bottling strength. Generally, the core range has relatively simple and stereotypical American oak tones (I imagine they’re dominantly sherry seasoned hogsheads organised by Edrington) with a hamstrung distillery character due to the low strength and probable chill-filtration. 

The independent bottlers, however, release some stunning stuff. To me HP has a characterfully dirty distillate with prominent organosulfurs, good viscosity and beautifully expressive peat. When the oak is well moderated, I find it shares plentiful character with some of our beloved Campbeltown malts. This is especially true when the cask choice is suitably complimentary in style, such as this wee G&M bottle. I think we’ve had enough preamble, so let’s dig in.

Nose

Well it's certainly HP, although again finding echoes of Campbelltown. We're talking shoe polish, a little Dijon mustard, light pickled onion and the expected passion fruit/grapefruit combo. Possibly a hint of new make aldehydes around the edges - puncheons are large after all. The peat contributes some soft shellfish, mechanical oils, worn rubber, a nice fustiness plus ripe lime and traces of chalk. Water lifts out some cask influence with cinnamon, soft toffee, wood varnishes and walnuts.

Palate

The peat is bigger here - used engine oils and lighter hydrocarbons, roasted cacao notes plus some gamey smallgoods, flint and soot. Slight vivacious new make with some acetic/wood glue tones on retronasal- not young, but youngish for 13, although the passion fruit helps here. The cask gives some good blood orange liqueur, black liquorice, a mild cinnamon/cumin blend and a very light marzipan rancio on the finish. Water brings out a more sooty smoke, savoury oak spices (expectedly French) and a few delicate mixed berries. 

The Dregs

Had this cask been left to get to its late teens or perhaps even early twenties, we would have an utter stunner. As it is this is a very good whisky that shows a lovely spirit forward style with the complimentary cask augmenting rather than dominating. Essentially, this is my kind of whisky. Generally speaking my preferred cask type is some kind of refill bourbon hoggie, however certain distillates can better suit other profiles depending on circumstance. Sherry casks are still such a pot luck for me unfortunately due to a sensitive disposition regarding sulphur, however this cask was evidently clean and well maintained. Kudos G&M, not that any of us should be surprised by now.

We could almost argue a point loss for retail value, but at the price I paid I am quite happy with where it sits.

Score: 7/10

Tried this? Share your thoughts in the comments below. TK

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