SAPS: Wine fermentation, ethanol releases and sequestration

Number 4 in the Sustainable Agricultural Practices Series.

In a book I’m re-reading – yeah, it’s that good! – Walkable City: How Downtown Can Save America, One Step at a Time, author Jeff Speck makes abundantly clear how right here at home the air pollution dynamic had shifted. Instead of the vast majority of the country’s smog-pollutant emissions emanating from industrial stacks (as apparently was once the case) it is now mainly vehicle-exhaust-pipe-sourced.1

There are no more miles being driven on American soil than right now.

As a matter of fact, in 2015, an astounding 3.148 trillion miles were logged. This easily tops 2014’s record of 3.041 trillion miles, the second highest in U.S. history, a difference of 107 billion miles – tantamount to a trip to the sun and back 1,150 times.

No surprise then that the places the car is king – cities like Los Angeles, Houston, Atlanta – are also smog trouble spots.

Besides transportation, another smog-forming-emissions breeding ground is agriculture. One type of operation which might at first seem an unlikely source but is one nonetheless, is wine making and, specifically, the fermentation activity.

Fruit of the vine

In case you’re wondering just how extensive wine-grape growing in the U.S. is, just the export market of domestic wine production alone is a roughly $68.4 billion per year industry, this based on a 2012 Wine Institute study, according to Diego Abeloos in “From Grape to Glass” in the Fall 2015 Cal Poly magazine issue. And, that’s just for wine exports.

In order to turn grapes (or other fruit) into wine, as a part of that process is fermentation. However, not all that is connected with grape fermentation is desirable.

For example, a required ingredient which helps facilitate the fermentation process is yeast. During fermentation, when yeast is combined with natural sugars present in grapes, various aromas and/or vapors and/or gases are released, in this case the vapor being ethanol (EtOH); the gas being carbon dioxide (CO2); so-called byproducts. (For further information, see: “An Introduction on Low Temperature Fermentation in Wine Production”).

Ethanol, as a vaporous substance, alternatively is known as an air pollutant – a volatile organic compound (VOC) or smog-forming emission, in other words. Based on the number of wineries that there are, this, coupled with fermentation, translates into a considerable amount of vapor ethanol released. To help address this in California’s San Joaquin Valley, there is Rule 4694. (For more about this, reference: “Rule 4694 Wine Fermentation and Storage Tanks,” a San Joaquin Valley Air Pollution Control District rule).

Keeping in mind that a reduction in VOC corresponds to a reduction in smog, what if there was a way or ways to cut back on the amount of said ethanol releases and thereby lessen its VOC impact? Well, there is (are).

You can think of this action in the following way: a kind of wine-fermentation-produced-ethanol-vapor-capture-capability. That definition may be a crude one, but it does, at its most fundamental level, sum the situation up.

For much more about this side of the wine-making operation, look here.


  1. Jeff Speck, Walkable City: How Downtown Can Save America, One Step at a Time, 2012, p. 44

– Alan Kandel