Article

Evaporative Cooling

The grapes and apples are picked, crushed and pressed. Everything is a go for fermentation. Except it’s too hot! You want a cool fermentation, around 60 °F (16 °C), but the coolest space in the house is 70 °F (21 °C). Short of buying a new refrigerator or maxing out the air conditioner, what is one to do? You might consider evaporative cooling, which is a simple and inexpensive way to cool a small fermenter. Many wine and beer styles require cool fermentations (for example, white wines, ciders and lagers). Cool fermentations produce fresher and more fruity wines, helped, in part, by the greater production of aromatic fruit esters, such as isoamyl, isobutyl and hexyl acetates (see R.S. Jackson, Wine Science, 1994). Failure to ferment under optimal temperatures can result in off-styles, or worse, off-flavors. For example, high temperatures (greater than 86 °F/30 °C) can inhibit yeast growth, leading to stuck fermentations and overly-sweet wines. Evaporative cooling means using the power of water evaporation to cool a fermentation. If the wet evaporating surface surrounds your fermenter, evaporation literally sucks energy,