At the cornerstone of wine preservation is a robust and reliable climate control system. Temperature is an undisputed essential, while humidity is considered by some to be discretionary when it comes to protecting our prized vintages. Even serious wine collectors attempt to utilize comfort cooling units to maintain their investments, because they operate under the assumption that simply maintaining a consistent 55℉ to 57℉ (12℃ to 14℃) is sufficient. At Wine Guardian, we believe that temperature and humidity go hand-in-hand and have designed our systems accordingly. In order to understand why humidity is so crucial in the long-term storage and aging of wine we must begin with the science behind it.
The aging of wine is a biological process that depends upon the presence of oxygen. An intact cork will allow a small amount of oxygen into the wine, while releasing naturally occuring gases. There are misconceptions that tight corks and wrappers are impervious and prevent this exchange, which is incorrect. Corks and wine bottle wrappers are permeable specifically for this vital exchange or wine would not age. Moreover, wines in screw-top bottles do not age due to the absence of oxygen—and corks—and are meant for shorter-term storage.
There is certainly an acceptable range of between 50-70% relative humidity, so precision is not critical to protect the flavors and longevity of wine. However, in the absence of enough humidity, the cork will dry out and may crumble when the bottle is opened. In addition to bits of dry cork being pushed into the bottle, the appropriate exchange of oxygen and gases will be disrupted without enough moisture present and the wine may be degraded and evaporate.
Too much humidity is also problematic. In the presence of relative humidity levels above 70%, mold and bacteria may infiltrate and damage wine. Condensation throws off the aging process and may also result in labels peeling. More oxygen is present in excess moisture and will cause the wine to emit bad odors that jeopardize the quality of the vintage.
We hope that by having this understanding of the biological process behind aging wine collectors around the world are empowered to avoid the disastrous effects of considering humidity control optional.