DIY Custom Wine Cellar

Humidity Levels In Wine Cellars

Fussy little creatures, these wines! Once we have achieved a stable temperature of 15oC, the next thing to look at is the relative humidity. In order to understand this we need to consider how the wine is sealed.

Wine bottles are traditionally closed with the humble old cork, and although we are now seeing a number of better alternatives, alas, corks will still be with us for a long time to come. Being a natural substance, corks are somewhat prone to deterioration. They will not remain effective for long unless they are looked after. The easiest way to kill a cork is to dry it out. It will then shrivel, lose its seal, and the wine may begin to leak out of the bottle.

The cork can easily be kept moist on the inside by laying the bottle on its side to maintain contact between the cork and the wine. Keeping the outside from drying out requires a little more attention, and is best achieved by maintaining adequate humidity. Relative humidity around 70–80% is considered ideal. If the humidity is consistently below 60%, the cork will dry out.

Humidity throughout the ancient cellars of the old-world wine regions is regularly in the 80–100% range. At Marc Bredif in the Loire Valley in France, the innermost room of the cellar maintains a dead stable temperature of 13oC and a humidity of 90%. Vintages all the way back to 1874 lie perfectly preserved to this day. Well, almost perfectly. (I told you these bottles were fussy!) Bredif has recently constructed a very sterile climate- controlled warehouse to protect its new wines from excess moisture. Humidity above about 85% can cause labels to peel, cartons to rot and bottles to develop mold.