in any case, a while back, a friend of mine sent me a link for a curious product: polished granite cubes from Scotland meant to be chilled and placed in a dram of whisky to cool it, like ice. naturally, we mocked this product greatly, not least for the anticipated damage “granite cubes” would do to our Reidel single malt glasses, but mostly because, well… real men don’t chill their scotch.

however, having read your excellent blog post and the referenced article, i guess i can actually see a use for a product that could chill a dram below the point of aggregation, without at the same time diluting it beyond the number of drops needed to achieve the whisky’s maximum flavor profile.

i am in no way affiliated with the company or product, and despite what i’ve said have no plans for a purchase. however, just because it fits the discussion so well, i will provide a link here:

http://www.sippinontherocks.com/

thanks to all contributors for a thought-provoking read…

Although maturation might influence the alcohol level, many whiskies are typically diluted before botteling. So the alcohol concentration of the end product is not really influenced by ageing. One effect of maturation is that more compounds are extracted from the wood. These compounds influence the aroma both directly and indirectly (by formation of micelles and trapping). Therefore it would be a good idea to dilute older whiskies as well as younger ones to “unlock” the aroma.

I think the lenght of maturation would be more important - i.e. older whiskies would need more cooling/dilution.

For nosing the whisky I would recommend cold water. For drinking however, ice-cubes would probably be better since more cooling would release more flavour. Once in the mouth, the temperature would rise to 37 °C anyway. But there is a trade-off, since since cooling will release flavour from the ethanol micelles, but lower the vapour pressure (i.e. the whisky will smell less).

as far as the whiskey information goes…. i recently had a scotch tasting @ a restaurant i was working at, i was not a big scotch fan @ this time i prefered tennesee and irish for their lack of peat flavor & aroma… then i was instructed to dilute each of the scotch whiskeys as well as taste them straight up. the change in flavor was tremendous. its interesting to get the actual chemistry on why this happens. im sure this was discussed in the material but, would scotch be affected more by dilution or cooling vs other whiskeys (sans peat) due to the oils from peat smoke? i prefer my whiskeys w/ a little cold water, vs ice… i find when its too cold it has less flavor, but according to the info i might be wrong…. is there a tempature barrier, too cold? whats a good dilution ratio?

http://www.cbc.ca/news/background/senses/umami.html

As you can see from the original post, I didn’t mention ethanol aggregates at all, only the aggregates formed by the long chain esters upon dilution which are mentioned in the introduction. But thank you for discussing the importance of the ethanol aggregates! I certainly oversimplified matters a lot - which is probably noticeable from the fact that your comment is as long as the original blogpost But thanks again for bringing additional aspects to my (and other reader’s) attention!

At higher ethanol levels, the water/ethanol mixture is not as homogenous as one might think (Conner 1999, p1019):

…below 15% ethanol such solutions are monodisperse. Above 20% ethanol the water structure is unable to retain all ethanol molecules and the excess aggregates to form micelle-like structures. Activity coefficient data suggest that the monodisperse solution behaves as an aqueous single phase. In contrast, solutions of higher ethanol content behave as a micro-emulsion and the rapid decrease in activity coefficients is the result of incorporation of esters into the ethanol aggregates.

Thus, whisky still in the bottle is a micro-emulsion, which the esters being incorporated into the aggregates. By diluting it with (soda) water the ethanol aggregates disintegrate and the esters, i.e. the flavors, are released.

The temperature dimension (Conner 1999, p.1019):

The enthalpy of solution of ethanol is negative (-52.4kJ/mol) resulting in a lower solubility of ethanol at higher temperatures and consequently a lower critical point for aggregation [i.e. formation of an ethanol microemulsion].

Thus, there is a case for whisky on ice: The ice cubes cool down the whisky and bring the ‘stuff’ below the point of aggregation with a consequent release of the ‘flavors’ from the dissolving aggregates! One of the rare instances of more flavors by cooling the ‘food’.

Adding the maturing in oak casks (Conner 1999, p 1020):

Wood extract decreased the critical point for the aggregation of ethanol…

Thus, their need to be more dilution and/or cooling in wood cask matured whisky.

Furthermore (Conner 1999,1019):

Therefore, the reduction in the activity coefficient of ethyl decanoate [substitute flavor, a long ester] [in the headspace of the samples] in the presence of wood components could be the result of either more or larger ethanol aggregates with a greater capacity for solubilising ester.

As well as an annotated quote from the Conclusions:

High molecular weight esters [such as those from maturing in wood casks] displaced volatile compounds from the surface layer, resulting in lower headspace concentrations [of the volatile short esters responsible for the characteristic smell].

The maturing in wooden casks results in a greater capacity of the ethanol/water-mixture to incorporate shorter esters (bigger ethanol micelles), reduces the evaporation of the shorter esters (the longer esters are covering the fluid-air interface).

Do you have any idea, how these lines of reasoning (resulting from the same paper) could be made to converge?

One could add something to pull the micelles down, precipitate them.

This book, Food Processing Handbook, at the link below may be helpful

http://www3.interscience.wiley.com/cgi-bin/summary/112606273/SUMMARY

Costs $25.00 for the online version.

Chad,
For whisky - as far as I understood it - yes. But since the compounds are not listed I’m not sure about that. And addition of water will probably also mask some desireable aromas as well. Also I think it’s very hard to draw a line between desireable and undesireable aromas (cf. the comment above…) as this will depend on who you ask. I can’t think of any other system now where addition of water results in a masking effect like this.