In-bottle Maturation Experiment

I tried my hand at ‘bottle ageing’ some whisky recently. The idea had first been put into my head after meeting William Borrell from Vestal Vodka at Imbibe Live last June. William had been experimenting with oak chips (sherry cask and bourbon cask) as well as other woods, within the bottles and there was a noticeable difference in both colour and taste within just a short maturation period.

Later Ralfy posted a couple of videos where he went about changing some cheap supermarket blended whisky through bottle ageing whisky, using different wood species to change the profile. I wanted to try this (you can find Ralfy's videos here: Part 1 and Part 2)

I wanted to use American White Oak (Quercus Alba) for my initial experiment and started searching for suitable wood. Initially I was hoping to be able to find some ex-bourbon barrel staves but ended up with a craft wood supplier and bought a handful of pen blanks, five American White Oak and five European Oak (Quercus Robur) virgin oak pen blanks.

Ideally I was hoping to find an uncoloured whisky, but every one of the supermarket single malts seemed to be heavily coloured. Not wanting to mess up a distillery bottling I picked a 12 Year Old Highland Single Malt from Tesco, in hindsight it was perhaps a little too dark already, but at just £21 was a low risk experiment.

I can do science me

Following Ralfy’s video I dried, then lightly charred the outer edges of the pen plank using a blowtorch. I wanted to give some sherry influence to the Highland Single Malt so, I made a small tray from some aluminium foil to soak my ‘stick’ in after charring. I used a glass of Oloroso, and left it to soak into the charred pen blank while I hunted for a suitable maturation container that would allow my pen plank to be suspended in it. My original idea was to use a kilner type jar, that has a nice wide neck and a resealable lid, but in order to hold the full length of the pen blank would have needed more than one bottle to cover the wood. I settled on using an old wine carafe that I had a lid for, and decanted the bottle of single malt into it, while keeping a sample for a control, so I could compare the differences later.

I suspended the charred and sherry soaked pen blank into the carafe and left for around 12 weeks. Initially I was checking it regularly to make sure I wasn't over exposing it to the wood, but eventually forgot all about it, leaving it out in the garage to continue the process.

Last weekend I remembered it and decided I needed to check it out, I also had some old bottles that I needed to get some spirit into them to stop the corks from drying out, so killed two birds with one stone.

There was a slight colour difference, which was easy to see in the glass, but perhaps not quite as easy to pick up in the photograph. The difference in the nose was more pronounced as was the taste, and I was pleasantly surprised with what I found.

Whisky Discovery #726

Tesco’s 12 Year Old Highland Single Malt

Highland Single Malt

Circa £25.00 70cl

This was the ‘donor’ bottle for my experiment and chosen because it was reasonably inexpensive and readily available:

Nose: Quite gentle floral notes, not dominating though. Gentle honey notes followed with a herbal heather note and some peppery spices too. Not overly complicated but certainly in the highland style

Palate: Opens with a herbal sweetness, grassy with heather and gentle citrus notes. Spices come through towards the end with some peppery ginger heat

Whisky Discovery #727

Tesco’s 12 Year Old Highland Single Malt (40% abv)

A Bedfordshire modified Highland Single Malt

Priceless!

The one on the left has been modified in Bedfordshire

Colour: A slight colour change was noticeable, with the 

Nose: Sweeter immediately, richer honey notes coming through to the fore and much enhanced spicy notes, the floral herbal notes had been overcome with buttery vanilla and the charred wood notes were evident

Palate: A greater wood influence was also apparent on the palate, with wood shop and sawdust notes, sweet honey notes and the spices seemed softer but overall a much richer mouth feel was achieved. The spicy heat comes through right at the end, and finishes much drier than the original whisky

Verdict:

I was hoping for more sherry influence from my experiment, perhaps I should have left the wood soaking in sherry overnight, or even longer. 

I would have liked to see a greater colour change, and for my next experiment I want to use some lightly coloured spirit, or new make if I can get my hands on some. I’d also like to use a higher abv spirit. I’m going to stick with my Oloroso conditioning as usually have a bottle or three to hand, but would like to run one of each American and European Oak in two separate flasks to see how different they turn out.

Not long after watching Ralfy’s videos and while hatching my own cunning plan I received and email from a local micro brewery. He had found our blog and wanted us to come and taste his English Spirit. Our local micro brewery was making a number of different beers for the local area, but every now and then would send a batch of his wash to a local distiller who would distil and bottle his English Malt Spirit at 40% abv, coloured with spirit caramel.

I discussed my in-bottle maturation experiment with the brewer who showed immediate interest and I pointed him towards Ralfy’s video blog. I need to follow up with him now and see how his next batch has gone down, as he was going to try some of his own experiments, he might also be my source of new make spirit for my own plans.

Then I was thinking…

There is a huge demand for whisky right now, distilleries have been caught off guard and there is a rush to expand capacity. New distilleries starting up on an almost weekly basis, aged stocks being consumed so fast that many brands have been abandoning age statement whiskies at the younger end of the scale, creating new NAS (no age statement) expressions allowing distillers/blenders to use younger stock with the older maturing stock to make it go further and get product to market to meet the demand.

The current UK law states that to be deemed whisky the distilled spirit must be matured in oak casks for a minimum of three years. New distilleries have been selling their distilled spirit, matured in oak casks, at younger ages, to raise necessary cash flow, but it cannot be called whisky.

When maturing spirit in oak casks a percentage of the spirit is lost every year due to evaporation (known as the Angels Share) H.M. Customs allow for two percent a year which can amount to over 50 litres over a typical 10 year maturation.

This new demand must increase demand for casks, both new for Bourbon and second-hand for Scotch whisky, and with distilleries worldwide all in the market for quality casks to mature their spirit in, perhaps now is the time to investigate alternative ways of exposing wood to the spirit?

I'm damn sure that I can't be the first one to think along these line, but closed containers with oak staves suspended in the distilled spirit, as per my in-bottle extra maturation experiment might be worth investigating on a larger scale. The planks could be thinner as all sides of the wood would be used, expensive quarter sawn timber would not be necessary as their would be no structural requirements. Yield should increase as the Angels Share losses should be almost eliminated. Perhaps with a larger volumes of maturing spirit, temperature would remain more consistent and with careful calculations just the right volume of oak wood could be used to maximise the life of the ‘plank’ whilst reducing the maturation time, and producing consistent quality. The oak planks could be pressure infused with Sherry, Port or any number of other wines currently used in cask form to finish whiskies, to create the whisky profiles we currently enjoy.

Perhaps this is a step too far right now, but surely things will need to change in the future? The demand on managed forests will eventually outstrip the supply of suitable cask timber, and how many times can a cask be 'rejuvenated' before it's lifeless?

I would love to hear your thoughts, but in the meantime I’m looking to start my next in-bottle maturation very soon, and perhaps an English Malt Spirit which has had oak influence in this manner might start a trend from the new craft distilleries.

Slàinte! Dave

E150a Experiment

This is the brainchild of Johanne McInnis, aka @Whiskylassie and one half of The Perfect Whisky Match Blog. 

The idea originated way back in February, when Johanne, who has a  background in chemistry, announced her intentions on our Whisky Bloggers Facebook page,  after reading an article on the Whisky Science blog. Johanne asked for ten interested bloggers to step forward. Overwhelmed by the response the number of participants has increased to around two dozen of us now.

Johanne got hold of some E150a from an undisclosed source that works in the "brewing" industry, and then went out to purchase two identical bottles of known naturally coloured whisky from her local liquor store. Then based on a equation and information from a distillery "source", Johanne calculated how much of the colourant to add. One of the two bottles has 1.2g/700ml or roughly 1 drop of Caramel for every 15ml of Whisky.

These formed the basis of the kits that have been sent worldwide. Each kit also included a small vial of neat E150a and a small pipette so we too could conduct our own experiments, and I will be trying this again later.

I'll start this post with a brief introduction from Johanne:

The majority of single malts and virtually all the blends from Scotland are coloured with E150a. The SWA regulation of 2009 states that “plain caramel" (E150a) is allowed. HOWEVER, this is just a guideline. In fact, UK and EU laws permit the use of their definition which is “spirit caramel”. Which means any of the four caramels E150a-d can be used by the distillery.

Four different types (a-d or from class I to IV).

E150a (distiller’s caramel) is made by a process involving a controlled heat treatment of a carbohydrate. Mostly used are glucose, syrups, sucrose and/or dextrose. Although each manufacturer protects their trademark, most use the same process which involves adding acids or bases to promote the caramelization of the CH (carbohydrate) compound. This colouring agent is used in very small quantities. Fructose based E150a produces the darkest range of colours. It starts to caramelise at 110C. E150a is the most stable of caramels as it can tolerate high ABV’s (75%) and it is also the most resistant to fading.

How much do they use?  Again, it seems to be a guarded secret with most distilleries however on average we know it’s about 1.0 – 5.0 grams/Litre (that translates to 0.1 – 0.5 %)

So the question was can you detect a difference in your whiskies?  You will clearly see there is a difference in the colour of the whisky but can you truly detect on the nose and/or palate in a blind taste test?   Let’s find out:

All set up ready to start the first E150a experiment - I can do science me!

First of all what does neat E150a smell and taste like? You can see the small black bottle in the photo above, with the pipette alongside it. I can assure you that the glass vial is clear. The E150a liquid is a rich, viscous dark brown in colour, has the smell of burnt sugar, almost carbon like, the burnt sugar carbon note is clear on the palate too, and it starts to leave a bitter after-taste in the mouth, similar to the pith of a grapefruit, but a little more more unpleasant. 

A single drop in a glass of water is enough to make it look like a glass of whisky is in my hand. In hindsight, perhaps it would have been better to had  properly nose and taste the E150a first before conducting the tests, as it was I rushed headlong into conducting the blind whisky tasting tests without actually establishing what I would be looking for!

With shrouds constructed for the two nosing glasses and my youngest daughter in control of monitoring my blind tasting results, 10ml of each whisky was poured into separate nosing glasses. My first test took place in the afternoon. I correctly identified the darker whisky first time around, and to celebrate I pushed the boat out, had a cup of tea and a piece of cake. The second nosing occurred afterwards and I identified the incorrect whisky. Around thirty minutes later I revisited and was able to pick out the darker whisky correctly. The glasses were mixed up again for the taste test, and although I could detect a notable difference, I picked the sweeter whisky, which was incorrect.

The second test took place later the same evening, and interestingly finished a cup of tea before the first nosing and getting it wrong again. The next two nosing tests followed where I correctly identified the coloured whisky. I was still unable to pick the correct one on the taste test, choosing the sweeter tasting whisky again.

The final test took place the following morning, no tea in the morning for me this time, and I had a clear run through, identifying the coloured whisky by nosing correctly each time, and then picking the correct one on the taste test too. I think however by this third test I had learnt the differences and was able to correctly identify the taste immediately.

So what does this all mean? I haven't a clue apart from I am noticing a difference! I have questioned why brands feel it is necessary to colour whisky in some of my blog posts before,  as have previously been told that it is not noticeable.

The darker of the two samples smells richer, with more caramel flavours. The citrus notes are more lemon/lime in the lighter sample and more orange like in the darker sample.

However on the taste test the darker coloured whisky tasted bitterer - I was associating the darker richer notes found while nosing with the sweeter tasting whisky and was wrong on the first two taste tests. On the third taste test I remembered that the less sweet tasting whisky should be the coloured one and was correct.

The 'score sheet' from Whisky Discovery

And so concludes the results of the Whisky Discovery 'I can do Science Test'. My results have been sent off to our guru Johanne for collating and I'm looking forward to reading her blogpost on The Perfect Whisky Match once all the results have been analysed and her conclusion has been reached.

In the meantime, I will be 'doctoring' a small sample of naturally coloured whisky at home and repeating this experiment with Kat, more later!

All very orange! E150a samples being prepared in at The Perfect Whisky Match HQ