The highest proof bourbon that can be made is 160 proof. This is because bourbon, by legal definition, cannot be distilled at a proof higher than this. The reason for this limitation is to ensure that the bourbon retains its character and flavor profile. Distilling at higher proofs can strip away some of the flavors and aromas that make bourbon unique.
When bourbon is distilled, it typically comes off the still at a higher proof than what is desired for aging in barrels. To be considered bourbon, it must go into the barrel at 125 proof or lower. This lower proof allows for interaction with the wood and the extraction of flavors from the barrel during aging. The choice of proof at which bourbon is barreled can have an impact on its final flavor profile.
As bourbon ages in the barrel, a portion of the liquid is lost to evaporation, commonly referred to as the “angel's share.” This evaporation includes both alcohol and water, but the alcohol evaporates at a faster rate. This means that as the bourbon ages, the proof gradually increases. The longer it spends in the barrel, the higher the proof will be when it is eventually bottled.
It's important to note that the proof of a bourbon does not necessarily indicate its quality. While some people may prefer higher proof bourbons for their stronger flavors and more intense experience, others may prefer lower proof options for their smoother, more mellow character. It ultimately comes down to personal preference.
In my experience as a sommelier and brewer, I have encountered a wide range of bourbon proofs. Some of the highest proof bourbons I have come across are in the 130-140 proof range. These bourbons tend to have bold and robust flavors, with a noticeable alcohol burn. However, I have also enjoyed bourbons with lower proofs, around 90-100 proof, that offer a more balanced and approachable drinking experience.
To summarize, the highest proof bourbon that can be made is 160 proof, as dictated by legal regulations. However, the proof of bourbon can increase as it ages in the barrel, due to evaporation. The choice of proof at which bourbon is barreled and the resulting proof at bottling can influence its flavor profile. Ultimately, the choice of bourbon proof comes down to personal preference and there is no definitive indication of quality based on proof alone.