The proof lost in a whiskey club barrel can vary depending on a few factors such as the aging process, the type of barrel used, and the environmental conditions in which the barrel is stored. Generally, when whiskey is aged in barrels, a small percentage of the liquid evaporates over time. This evaporation is often referred to as the “angel's share.”
The proof lost in a whiskey club barrel is typically around 2-4% per year. This means that for every year of aging, the whiskey will lose about 2-4% of its original proof. So if the whiskey started at 120 proof, after one year in the barrel, it could potentially be around 116-118 proof.
The aging process plays a significant role in the proof loss. As whiskey ages, it interacts with the wood of the barrel, which allows it to develop complex flavors and aromas. However, this interaction also leads to some evaporation. The longer the whiskey ages, the more time it has to lose proof.
The type of barrel used can also affect the proof loss. Different types of wood and barrel sizes can impact the rate of evaporation. For example, smaller barrels tend to have a higher rate of proof loss compared to larger barrels. Additionally, the type of wood used in the barrel, such as oak, can influence the evaporation rate.
Environmental conditions, such as temperature and humidity, can also impact the proof lost in a whiskey barrel. Higher temperatures and lower humidity levels can accelerate the evaporation process, resulting in a higher proof loss. Conversely, cooler temperatures and higher humidity can slow down the evaporation, leading to a lower proof loss.
It's important to note that the proof lost in a whiskey club barrel is not necessarily a negative aspect. The evaporation process allows the whiskey to concentrate in flavor and develop unique characteristics. Many whiskey enthusiasts appreciate the complexity that comes from the aging process and the proof loss.
In my personal experience as a sommelier and brewer, I have had the opportunity to taste whiskeys that have been aged in various barrels. The proof lost in these barrels has varied, but it has always contributed to the overall flavor profile of the whiskey. The caramel and baking spice notes that you mentioned in your question are often enhanced through the aging process and proof loss.
To summarize, the proof lost in a whiskey club barrel is typically around 2-4% per year, but it can vary depending on factors such as aging process, barrel type, and environmental conditions. This proof loss contributes to the development of flavors and aromas in the whiskey, resulting in a full-flavored and complex spirit.