CRISPR beer

A startup called Berkeley Brewing Science is using a gene-editing tool knows as CRISPR-Cas9 to make hoppy beer without hops. Hops are very cool, I grow a few varieties in my back yard. They are beautiful plants, bines actually, not vines, as they climb by twining and not by suckers. Commercially the male plants are ruthlessly excluded from production in order to prevent the females from being fertilized. Like sinsemilla pot, the fruits (called cones) become laden with the desired essential oils and are then harvested, dried, and processed. My plants came from rhizomes and most cultivars of hops (Humulus lupulus) are clones and are propagated vegetatively, much like cannabis.

So why make beer without hops? For one, hops are thirsty. It is estimated that 100 billion liters (100 GL) of water are needed annually for the U.S. crop. For perspective, the harbor at Sydney in Australia holds about 500 GL of water. In fact, that amount, 500 Gigaliters, is known as a “sydharb” (thank you Wolfram Alpha). And people think Austin Sendek‘s “hella-” prefix (as in the Earth has a mass of six hellagrams) is silly.

Imagine doing something environmentally friendly like reducing water use with a technology that greens love to hate, gene-editing! Certainly that is not the only reason to make beer without hops. The main reason, I expect, is to increase the brewer’s control over the product. Hops introduce a lot of variability and even the small craft brewers want consistent flavors even if they aren’t as paranoid as those who oversee something like Budweiser.

One of the features of modern life is increased quality control. The drugs we buy today at the pharmacy are cleaner and purer than drugs have ever been. Our food supply is far more predictable and much safer than ever before. Even the recent E. coil—Romaine lettuce scare affected only a few dozen people in a nation of 340 million. And it was unusual in that the CDC could NOT trace the source of the infection. Usually they can track that stuff down. We are so spoiled by quality control that we reject pharmaceuticals in favor of “natural herbs” and we crave “authentic” and “local” foods instead of mass-produced ones. This despite no evidence that the modern stuff is unhealthier and the “retro” stuff is healthier. If you slap a picture of a farmer in overalls next to a happy cow on your cheese package people will pay extra.

An article in Nature Communications (Industrial brewing yeast engineered for the production of primary flavor determinants in hopped beer by CM Denby, RA Li, et. al.,) has this wonderful line:

While historic consumer trepidation towards genetically engineered foods is of concern for widespread adoption, the general increase in consumer acceptance of such foods when tied to increased sustainability is encouraging.

I’d say cost and taste matter more, but this works, too. The beer produced in the study quoted above apparently compared favorably to hoppy commercial beers like Sierra Nevada’s Torpedo IPA. But taster panels, even trained ones, display a lot of variation so we’ll see what happens with actual beer consumers. I expect they’ll be quaffing pints of the stuff sooner than they’ll realize. I’ve no problem with such beers, no one says you actually have to use hops. If you think about it, the malt already contains the precursors of the chemicals that create hop flavors! The gene-editing allows the new yeast to activate bio-synthesis pathways to produce geraniol and linalool which are naturally-occurring terpene alcohols present in many, many aromatic fruits, flowers, and other plant parts.

The researchers used gene sequences from basil (Ocimum basilicum) and a mint (Mentha citrata) to engineer a brewer’s yeast (Saccharomyces cerevisiae) to produce more of the desired geraniol and linalool during fermentation, enough for tasters to perceive as hop flavors in the finished beer. Obviously hops themselves are more complex than just these two molecules, and create, presumably, a broader taste palate. But this kind of application is only just beginning and I expect that brewers will have a much larger yeast toolkit very soon. As a homebrewer I have access to at least three dozen commercial-grade yeast strains in both liquid and powder form for a relatively low cost where there were only a handful thirty years ago, and nowhere near the quality.

I blogged about CRISPR a while ago (you say “crisper” just like it looks) and I’m pretty much squarely in the camp of the GMO-enthusiasts. I’ve no fear of Dr. Frankenstein. There’s a fellow recently who claims he’s made CRISPR-modified babies although some don’t believe him. Regardless, it is a chilling thought. Few would be opposed to gene editing that helped a baby overcome a birth defect and thrive rather than suffer. But such things are hard to draw boundaries around, and the general feeling is that experimenting on humans is at least ethically dubious, if not entirely barbaric. We are facing those questions now as bioengineering is mainstream stuff, not science fiction. The boundary lines will blur quickly when take-home GMO kits are available at Rite-Aid, and I don’t think that’s as far away as we want to believe.

In the meantime I hope the folks at Berkeley Brewing Science can cook up a homebrewer’s version of their no-hops-needed yeast. I’d love to try it.