is Whisky Oxidisation/Oxidation a Myth?  

wow you have sent me down the rabbit hole Neil! Okay so I have done a whole bunch of reading and this is what I have found although parts of this is covered above. Ethanol is a primary alcohol and therefore is susceptible to Oxidation as the oxygen wants to bond to anything it can. But this has already been happening in the barrel (which does help make the whisky more rounded over time but the tannins also play a part. What percentage each part plays I don’t know) but I think it’s very fair to say that Oxidation is a very slow process otherwise whisky wouldn’t last long in a barrel before it comes off as bland. It will be quicker with a smaller volume of whisky in a bottle full of air but still a slow process i.e. weeks/months up to a year or 2 dependant on ratio of whisky to air. But oxidisation is not the only thing happening in that bottle. Evaporation is happening also and I can’t see a way to do an experiment where you would be able to text one over the other. The molecular structure in the whisky either way is technically the same as the bonding has already happened in the barrel. But oxidation and evaporation will just lead to less and more of certain molecules. And interesting thing I found is that the molecules associated with taste and smell that we like from whisky at 45% abv or below tend to sit at the surface of a whisky whereas more cask strength whisky these molecules sit further down which is why both adding water or letting a glass sit and essentially evaporate help bring these molecules to the front. It’s evaporation, adding water or even swirling whisky that lead to the dissipation mentioned in your video. Back to the bottles though. With imperfect seals. Air in the bottle and the airflow that can come in via bad seals it is said that the average bottle looses 2% abv per year. I stopped trying to hold on to whisky with little amount left on the bottle as I did find a lot of them went “flat”. My change of pace is that if I want to taste a whisky further down the line I’m going to start archiving samples from the neck pour so that I am in control of the amount of air that whisky is exposed to. In short I think you are right we use the term oxidation wrong mostly even though it is present I don’t believe it’s the thing we are meaning when we are explaining a drastic change in the whisky taste even though it likely still plays a part

Being a PhD synthetic organic photochemist, I am convinced that the most important factor for changes in whisky in a bottle with time is in fact dissipation. The various organic molecules in whiskies are rather inert, so they won´t really react with oxygen. There may be de-esterifications and re-esterifications taking place, given a changing acidity (pH level) with time. Moreover, there will also be some photochemical reactions based on the fact that bottles are often stored in (scattered) daylight and these can be quite substantial (regarding flavour and aroma impact) as they really "break down" organic molecules. We all know that a whisky in an uncovered glass is losing aromas, ethanol and flavours, that is essentially what happens in slow-motion in a bottle. Even evaporating water will change the "broth". 😁 The neck pour subject is pretty easy to explain: The most volatile molecules will be trapped in the closed bottle, waiting to be released upon the cork being popped for the first time. They will fade at a given speed. The thing about certain whiskies needing some "air" is nothing but a rather unpredictable combination of dissipation and some (mostly photochemical) reactions happening that will change the "mix". Lots of myths in whisky, just run a blind tasting and you will find out how poorly people judge whiskies in various aspects...

INTERESTING!

I think it’s more evaporation in the glass. Oxidation in the bottle. The higher the proof the higher the evaporation. I had a bottle of ardbeg 10. About 15 years at 50% level. It completely changed. Lot less smoke and loads of vanilla.

I’m confused Did you just do a whole video without a dram in hand 🤔

in my limited experience a bit of air in the bottle generally improves the whisky. case in point the sadly missed arran 14 - on the first 1/4 of the bottle there was a jarring liquorice note that kept popping up to ruin the fruit basket, after a couple of months it buggered off and the bottle really started to shine. kilkerran 12 for me has a copper penny/metallic thing on the finish that goes away after a handful of drams that i sometimes miss as the bottle gets lower and better. the one dram i can think of immediately that fades the longer you leave it open is laphroaig 10. oh and bowmore 12 starts ok but is borderline undrinkable past the halfway point - same goes for most juras ive had.

I'm not a chemist, but what I do know, is that the contact between the whisky and the oxygen or air impacts the flavour. If anything, I believe your explanation actually makes a lot of sense. I also think a lot of people use the terms oxidation/oxidisation and dissipation interchangeably (or use the term oxidisation when they mean dissipation as the former has become a bit of a commonly used term). I therefore now vote we stop using the terms oxidation/oxidisation and dissipation and start talking about aeration as 'the weird thing that happens as a bottle becomes more empty and inflences and changes the flavour of the whisky'. There, repeat after me: AERATION!

Ralfy gases his bottles with wine preserver. I personally decant into smaller bottles.

Oxidation or dissipation? I have no idea which of those terms is truly accurate. What we whisky fans do know is that most whiskies will change to some degree once opened. The really interesting part of that change is why do some whiskies benefit after being opened, while others do not?

Sounds like the perfect opportunity to introduce the electric whisky vacuum bottle :) Got my coin, love it, cheers Neil.

So, our whiskey is shaped more by oxidization, or infusion from the oak barrels...? I believe the flavour profile comes from both, infusion of some flavours from the wood barrels and then again by the evaporation of the ethanol......(and I guess the color/flavour additives assist as well) Hey, great video. Great topic - I'm trying to find the best way to flavour some shine)....🥃🤔

Interesting thoughts. Currently do not have the time to run down the science. I expect we use the term Oxidation as a carry over from the wine industry. However, I do not know the specific phenolic composition in most whiskies, nor their relative reactivity with oxygen, nor how much estrification occurs after casking, etc. I am content to change my language to just refer to open time or air time or something less scientific. I have experienced that whisky changes open in a bottle over a few years. Not always dramatically. The science will need to come from a paid lab tech! Thanks for sharing.

This is definately a very interesting topic. One thing I would like to be able to test, is to stick a hydrometer into the bottle and to see if the abv changes.

Litle late comemt. The absolutte best example of a whisky geting better when aired is the Illach cask strength. From a bad acetone whisky to a complex fantastic whisky. All cheap scotch whisky like the queen margot 8 you rewieved gets wors when aired plus some few single malts like laphroig quarter cask . Why it,s so. No idea. But we learn by passion and time.

That’s a good idea to decant whisky for later reviews. I’ve only experienced this happening with one whisky. Wasn’t bad and wasn’t good either but after a few pours and it sitting on my shelf for about 4 months. It definitely tasted better and that’s all that matters to me lol

Oxygen and light does no favors in my experience. Damn interesting my friend.