DNA Drinking

by Recent Studies

Humans have been altering the genome of many plants and animals for thousands of years.  The wild “natural” grape still exists in parts of Eurasia and north Africa but bears only a passing resemblance to its relatives cultivated for the wine trade.  Wild grapes are dioecious , meaning male and female flowers are found on separate plants while the grape cultivars in wine production are hermaphroditic (having both male and female parts on the same plant).  In addition, grapes on wild plants are small and much lower in sugar content than their beloved cultivated cousins.

single hop

Hop growers constant release new hop strains with high alpha acids each year, but no one protests about this modification.

These significant biological changes may be a result of random mutations, selective breeding by humans, or most likely, both.  Humans select plants with the traits they most favor—larger grain size, larger grape bunches, more sugar content in grapes, and breed those plants together to encourage these traits.  This is called artificial selection and has touched and altered (many times very significantly)  nearly every cultivated crop and animal used by humans today.  Only recently, with the advent of biotechnology, have humans been able to alter the genome of plants and animals directly with genetic engineering—which generally means the insertion of a useful gene or trait from an unrelated source into another genome.   Although genetic engineering is essentially in its infancy, it is starting to be tested on the plant and microbial species used in beer and wine production.

Resistance is not futile

Currently, the most common application of genetic engineering in beer and wine ingredients is genetic alteration to confer resistance to some negative factor such as disease or herbicides.  Researchers from around the world at a variety of institutions are inserting genes for resistance in barley, hops, and grapes.

In barley, researchers have inserted a gene from a fungus which attacks other, damaging fungi in an attempt to provide some resistance to fungal root rot. Fungal root rot significantly impacts barley production, reducing yield, and selective breeding within the barley genome attempting to breed resistant strains hasn’t been very successful.  Field trials of this fungal resistant barley are currently underway in Germany.

A similar situation is occurring with hops. Powdery mildew is an extremely annoying and damaging fungal disease that is the bane of gardeners and hop growers alike.  Researchers are testing a genetically modified hop plant which has genetic material inserted from a soil bacteria to provide resistance to this disease.


How much of an organism's DNA are you willing to change for the perfect beer or wine?

Why would you want a plant to be resistant to herbicides?  Aren’t they supposed to kill plants?  Well yes, but only the plants you want to kill.  2, 4-D is a commonly used broad leaf (as opposed to grasses which are narrow leaf) herbicide commonly used in the Midwest on corn and other crops.  Unfortunately 2, 4-D also effectively kills grapes, even grapes a significant distance away from a sprayed field.   Researchers at the University of Illinois have inserted a gene from a bacteria that breaks down 2, 4-D into grape plants in an attempt to develop a 2, 4-D resistant grape vine. This would allow people who wished to grow grapes in heavily agricultural areas to do so without worrying their investment might be inadvertently destroyed.  This genetically modified (GM) grape is currently undergoing testing.

Other researchers are investigating and testing transgenic grape vines for fungal disease resistance. These vines have a gene inserted for an enzyme called chitinase—which degrades chitin, a main building material of fungus.  Early field trials in Germany however, show these genetically modified grape vines don’t show any more resistance to fungal infection than normal vines.  Research on this type of front however, is ongoing in different places.   Grape vines with disease resistance would translate to less use of the chemicals used to treat and prevent these diseases.

  • Reseachers have genetically modified barley to be fungal resistant
  • New grape vines are resistant to 2, 4-D, a common herbicide, so the vines be grown near agricultural areas
  • Disease resistant crops would require less chemicals used on the grapes

Improving fermentation

The creation of some wine styles—including chardonnay—involves a secondary fermentation process that occurs after the primary fermentation (where grape juice is converted to alcohol by yeast).  This secondary fermentation, called malolactic fermentation, is accomplished by the use of a bacterial starter to convert malic acid to lactic acid, which creates a more pleasant mouthfeel  and a less “sour” taste in the wine.

The bacteria that mitigate this conversion are somewhat finicky about temperature, competition with other microorganisms etc.. so there are some frequent problems during this process including stalled fermentation which can result in spoiled wine (bad for everyone!).   Prior to the advent of biotechnology, wine yeast could not accomplish the conversion of malic acid to lactic acid as it lacks the enzyme to do so.
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Researchers at the Wine Research Center at the University of British Columbia however, have managed to genetically engineer a wine yeast (Saccharomyces cerevisiae) that has the enzyme needed for malolactic fermentation—it was taken from the bacteria that usually performs this job (Oneococcus onei).  This genetically modified yeast, called ML01, is the first genetically engineered wine yeast approved for use by the Federal Drug Administration in the United States, and Health Canada in Canada.

Other genetic engineering efforts in regards to fermentation include the splicing of heat resistant bacterial glucanase genes into barley to improve the malting process.  Brewers malt barley by soaking the barley seeds in water to start germination.  During germination, enzymes convert the starches in the seed to sugars which can then be fermented.  Brewers must stop this process however, before the germinating plant starts to use the sugars for itself—which brewers do with heat.  Heating germinating seeds however, also stops the action of the enzymes doing the work the brewers want done.  Barley with more heat stable enzymes means they will continue to do the conversion work after the grains have been exposed to heat to halt germination, making the process more efficient.

  • University of British Columbia modified yeast to ferment the wine and perform a malolactic fermentation at the same time
  • Researchers are working on making barley heat resistant to improve malting

All wine grapes have been genetically selected for. Still places like France and South Africa are against genetically modified grapes.

The Specter of Frankenwine

To say there is opposition to genetically modified organisms would be an understatement.  Many groups and individuals (indeed, entire countries) have expressed concerns and opposition to the development and use of genetically modified plants, animals, and microorganisms—including all of the ones discussed above in relation to the production of beer and wine. Concerns include safety for human consumption, ethical concerns about corporate dominance in the food market, and potential environmental damage.

Proposed and ongoing field testing of genetically modified grapes has caused a stir in France and South Africa, with much of the opposition coming from existing wineries concerned about “genetic pollution”—the unintentional spread of genetically modified grapes by cross pollination, or by the distribution of GM grape seeds by vectors such as birds.  Wine is a product that depends heavily on idealized romantic notions of the interaction between humans and nature, and genetically modified organisms don’t fit in with many people’s ideas of this relationship.

This particular concern about genetically modified grapes seems to boil down to “they’re not natural”—a somewhat ridiculous argument considering the extensive manipulations humans apply to nature to produce wine now—artificial selection of grapes for generations, the application of herbicides and pesticides, the extreme soil disturbance of plowing, none of which is natural.  This also assumes natural automatically equals good, perhaps forgetting for the moment that hurricanes are natural as are kidney stones.

  • Not everyone feels GM grapes are a good thing – especially France and South Africa
  • Grapes have been selected and modified for centuries
  • Grapes are rarely grown from seed, so cross contamination from pollination is very unlikely

Rational or not, it is the perception many consumers currently have of genetically modified plants; research for this article pulled up multiple articles from different sources mentioning the idea of “frankenwine” in relation to GM grapes.  Therefore, the concerns of the winemakers are understandable, any blow to the “natural” perception of their product could be damaging to the wine industry.  There is much less mysticism surrounding the production of beer, and as a result, less opposition to the use and development of genetically modified organisms in its production.   More testing will determine if other concerns, such as the health and environmental concerns raised by GM opponents, are valid.

Further Reading

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DJ Spiess

DJ Spiess

Beer buddy

I live in Denver, Colorado. This blog is everything about beer, wine, cider, mead and other spirits.
I am a avid homebrewer and winemaker. I’ve been making my own beer and wine for many years. I started making beer when I was in college (mostly because the drinking age in the United States is 21). My first few beers were horrible. The beers are much better now, and I often supply my neighborhood with free beer! It is a great hobby!