Aging- Barrel Strength vs. Flavors?

[Jonathan Forester]

Are there any tables or other information that describe flavors picked up when aging spirits in barrels or on wood at different strengths? I'm trying to figure out how to get certain desired flavors from barrel aging whiskey, brandy, and rum; and am having trouble finding any info on this.

[Ben Randolph]

I have not seen any info on it in those terms, the only stuff I can find is quick statements from scotch distilleries stating that 63-62% seems to be the standard. It would make sense that different levels of alcohol would induce different extractions from the wood but no one mentions this idea. I think these guys are more concerned about maximizing profits through barrel management and the perfect ratio of angels share and dilution.

Many of the flavors imparted from the wood have to do with the origin of the wood, what was previously in the cask, and the varying levels of char and toasting.

Hope this helps,

Ben

[will]

Are there any tables or other information that describe flavors picked up when aging spirits in barrels or on wood at different strengths? I'm trying to figure out how to get certain desired flavors from barrel aging whiskey, brandy, and rum; and am having trouble finding any info on this.

...just reading about this now...

No, Jonathan, not in tabular form. The reference I'm reading was recommended to me by Bill Owens, and it's right here...in chapter 7: Maturation and Blending.

Whisky: Technology, Production and Marketing

Handbook of Alcoholic Beverages series

Edited by Inge Russell

Academic Press

© 2003, Elsevier Ltd.

This book covers Scotch whisky, but the info applies to other matured spirits as well.

As Ben said above, any number of factors will affect the outcome. Clearly among those are (1) the original constituents (type of wood, depth of char, spirit strength, etc.), (2) Time, (3) Temperature & temp cycles, (4) wood surface to spirit volume ratio, (5) internal barrel pressure, (6) permeability of the barrel (evap. of spirit (etoh & h2o) and ingress of o2), and (7) Humidity.

from pp221:

"Scotch whisky maturation

Maturation can be viewed as the specific combination of one type of distillate with any one type of cask leading to the development of a flavour profile relative to time (Philp, 1986). Modern analytical techniques have been used to identify an increasing number of reactions that take place during whisky maturation. Most of these reactions are identified by chemical changes, and their influence on the sensory properties of a mature spirit has not been clarified." (my emphasis)

Another interesting observation, from pp 212: "while maturation of a Scotch malt whisky in a new charred oak cask may produce a well-matured whisky, it may not be readily identifiable as a Scotch (Clyne et al., 1993)

Big producers have dozens of casks to blend from, even from a single year. This means that they can make corrections for unbalanced flavor profiles, while micro-distillers are forced to hit the nail on the head with each stroke of the hammer.

You might want to consider a few tests in Mason jars with some of the toasted stave products available. This will allow you to get some ideas while working in small volumes. Don't expect to be able to duplicate a 30 year old Ardbeg in only a few weeks...it doesn't work that way!

will

[Whiskey Taichou]

The book he just mentioned is a great resource, though expensive. You can find it here.

It goes into some of the chemistry of barrel ageing.

[Paul G]

Are there any tables or other information that describe flavors picked up when aging spirits in barrels or on wood at different strengths? I'm trying to figure out how to get certain desired flavors from barrel aging whiskey, brandy, and rum; and am having trouble finding any info on this.

Perhaps this might help:

World Cooperage Barrel Profiling

Further, the toast temperature has been quantified as follows:

(Originally from World Cooperage)

[Palmetto Coast]

Are there any tables or other information that describe flavors picked up when aging spirits in barrels or on wood at different strengths? I'm trying to figure out how to get certain desired flavors from barrel aging whiskey, brandy, and rum; and am having trouble finding any info on this.

Edward Hamilton from The Ministry of Rum details the following (though not exactly what you are looking for...):

"Most rum producers age their rum at 70% to 80% alcohol. A few dilute their spirits to nearly bottle-strength, 40 to 45% alcohol by volume, before putting the barrels away for aging. A lower alcohol content during aging tends to leech slightly lighter esters and phenols from the wooden barrels while a higher alcohol content will attract heavier compounds and associated flavors. Most distilleries age their rum at a higher strength as this requires fewer barrels, but a higher alcohol content also contributes to higher evaporation losses, known as the angel's share."

[Jonathan Forester]

Thanks for the input folks, and I appreciate any more that comes forth on this subject.

I have a copy of Whisky: Technology, Production, and Marketing. i got it a week or so after I posted this question. On page 230 there is one paragraph on the subject of fill strength. It's a start, but leads to much more research. At least they mention two articles on the subject of fill strength.

Since then I have done some experiments, but it's slow. I have found that what goes on in a jar with wood chunks, is different from what happens in a barrel, and different size barrels at that. Toast, char, time, size, fill strength, the type of alcohol, used vs. new barrels; they all cause different flavor production.

Right now I'm playing with starting at one fill strength for a period of time, the lowering the strength considerably and putting it back into the same barrel. When I have some solid conclusions I will write about it.