Mad scientists extracting ancient DNA molecules from fossilized amber, resurrecting long dead beasts and unleashing them on an unsuspecting modern world as part of some half-baked, twisted commercial scheme. Hollywood horsepucky you say? Think again my friend. Truth, you see, can be even stranger than fiction. A certain hybrid, made possible by frightening science, has recently come to my attention: The Tyrannosaurus Rat. No, not the ones living in the sewers under Manhattan; I’m talking about a beer, one unlike any the world has ever seen.

The first batch was brewed in 2006, when Peter Hackett of northern California brewpub Stumptown teamed up with famed mad scientist (and real-life inspiration for the Michael Crichton novel Jurassic Park) Raul Cano of California Polytechnic to brew a hybridized version of his Rat Bastard pale ale that is nothing short of an abomination. What was so different about this simple pale ale? It was brewed with yeast that had lain dormant for 45 million years, buried deep in amber – fossilized tree sap – from an age before man, at the dawn of modern mammals.

Cano had generated a great deal of interest and controversy in the mid nineties by claiming to have cultured microorganisms (thousands in all) from the remnants of amber. Among the many species in his catalog were several strains of yeast closely related to Saccharomyces cerevisiae-he had found ancient ale yeast and brought it back to life! Cano never intended his research to create tasty beverages. In fact he had started his company, Ambergene, with the far loftier goal of synthesizing new antibiotics from the microorganisms, but the company later folded by 1997 when the investors (among them several major pharmaceutical companies) lost patience in the lack of progress. The only marketable idea that seems to have come from the venture was when a homebrewer on Cano’s staff decided to culture up some of the ancient yeast and brew a series of beers from it: T-Rex Lager, Stegosaurus Stout, Jurassic Amber Ale, and Ancient Ale. These beers were served at the wedding of Cano’s daughter, as well as the wrap party for Jurassic Park 2: The Lost World.

So how do you bring bugs back to life after 45 million years? Many microorganisms (including yeast strains) actually go into a state of deep hibernation when they run out of the things necessary to sustain life. If they are preserved from exposure to the elements, say by being trapped in virtually air- and water-proof fossilized amber, they can apparently stay alive and hibernate…for a very long time. This makes it relatively simple (I’m sure!) to reconstitute them; simply sanitize the bejeezus out of the outside surface of the amber (Cano used disinfectant, ultrasound, ethanol, and fire) to prevent modern contaminants from interfering with the sample, then dip it in liquid nitrogen to make it brittle, break it into many small pieces, and then stick it in a solution of microorganism chow and other nutrients and wait. The controversy I spoke of wasn’t so much over the risk of culturing some sort of andromeda strain from the amber or other ethical concerns, but more about the risk of modern contaminants. Most of the bacteria and other microorganisms Cano found were actually closely related to modern species, and considering 95% of modern bacteria has not been identified, let alone studied by scientists, it was hard to say whether Cano’s bugs were coming from inside the amber or outside. Even Cano initially thought the cultures growing in his petri dishes were contaminations that were keeping him from studying the dead bugs he was looking for, but with time this hypothesis changed, he isolated thousands of species, and his work was peer reviewed, replicated on several occasions by other teams, and eventually published in the journal Science.

And what about the beers? Cano’s Fossil Fuels Brewing Company is currently working with two northern California brewers: Hackett at Stumptown Brewery is producing a pale ale, and Joe Kelley at Kelley Brewing makes what can be referred to as a “Belgian” hefeweizen. Neither are available outside of northern California at the moment, but reports from the field indicate that the yeast features clove and other unique phenolics that gives the hefeweizen a bit of a “Belgian” feel. The strain has also been described by hacket as having a “gingery” tang, and several sources make mention of smooth fruity notes, citrusy but not overly sour. Either beer appears to be a must-have if you can get one.

So when will we get it on the east coast? Hard to say. They are expanding draft offerings (with presumably fake amber chunks in the tap handles) throughout California as we speak, and are in talks with contract brewers to ramp up production of bottles for wider distribution, but considering the fledgling brewing company has taken nearly three years to get this far, there’s no telling how long that will take.

So in the meantime, us Punks will have to wait (or pull together funds for that Pacific Coast Highway road trip we’ve always wanted to take) and see where this truly unique yeast will show up next. Reports indicate that Joe Kelley of Kelley Brewing would like to see it in a scottish wee heavy, so you’ll likely find it there before you find it at our local Sunset Grill and Tap, unfortunately.

If you want to listen to me geek out on this truly astonishing yeast strain from the perspective of a knowledgable homebrewer, don’t forget to check out my Technical Addendum.

In another post, we’ve told you all about the ancient yeast Raul Cano resurrected from fossilized amber, and the very special pale ale and hefeweizen that were created with it. Now down to business…time for this homebrewer to geek out on what makes this ancient yeast so very unique, and why the entire story is so special to begin with.

It should be noted right from the start that creating beer from ancient yeast was quite a long shot from the very beginning, and Peter Hackett of Stumptown knew this when he signed on to collaborate with Cano on the project. Even though we speak of ale yeast as a species (Saccharomyces cerevisiae), there is a great deal of variation within that species; the very variation that helps gives rise to the plethora of variety present among ales brewed the world over. Many strains of the yeast simply don’t perform well in the hostile environment that is wort, with its alcohol and acidity, not to mention the limited availability of oxygen. Any homebrewer knows that viability (health) of the yeast is very important, even with modern yeast…what effect would 45 million years in amber have on the viability of the strain? The bottom line is, this yeast was very unlikely to create a reasonable beer at all, let alone a critically acclaimed one which Hackett himself said was like nothing he’s ever had before.

To his credit, Hackett decided to press on, and found that this was indeed a very unusual strain. When first pitched, the yeast takes longer than most modern ale yeast to kick in, but when it does – make room. It has a very vigorous, even violent, top-fermenting initial phase that creates a very thick foam at the top of the fermenter. Then it does something I’ve never heard of in an ale yeast. It drops to the bottom of the fermenter, leaving the wort nearly clear. Normally this would be called flocculation and mark the approximate end of fermentation, when the yeast goes dormant to wait for more food (though more accurately a small portion of the yeast would remain in suspension and keep working longer, after other cells had flocculated). But Cano’s yeast doesn’t stop working. It keeps going, fermenting on the bottom of the vessel like a lager yeast would. Eventually, when fermentation slows to the point where the brewer is ready to put an end to it, they “crash” the yeast by cooling it to near freezing temperatures, causing any remaining yeast in suspension to finally give up and flocculate to the bottom so that they can be removed and the beer can be bottled. But here again, Cano’s yeast had other plans; refusing to crash, it simply keeps going – for another month! Apparently a 45 million year nap leads to an epic case of the munchies…

There are two other unique features about the yeast I’d like to mention. One is that it likes to work hot, even for ale yeast. It’s been used in a pale ale that ferments above 70 F, and a wheat beer that ferments at 68 F. My sources suggest that typical temperatures for these two styles would be something around 67 for a pale and as low as 62 for a hefeweizen (though there is some debate that would place it as high as 67, but I’ll go with Jamil Zainasheff on this one). I would speculate that this is because the Eocene epoch from which the yeast hails had a much warmer, tropical climate than the one we currently inhabit, and the yeast was evolved to this climate. My intuition would be that this higher temperature would mean more esters and phenols (fruit and spice) in the finished beer, and tasting notes of others (which were discussed in our other article) seem to bear this out.

Another unique feature is that the strain is apparently unable to digest any but a small range of carbohydrates, far fewer than modern brewer’s yeast. Cano believes this also contributes to the spicy character of the finished beer, though I’m not sure why since I’ve never heard of unfermentable sugar lending a spicy character to beer. On the other hand, unmalted wheat and rye are often described as lending a unique spiciness regardless of the yeast used, so maybe he is on to something. This does remind me of something I read recently about the difference between beer yeast and wine yeast. Apparently wine yeast also works with a smaller range of carbohydrates, and this gives beer made with wine yeast a cloying (overly sweet) finish, unless it is coupled with a beer strain or enzymes are added to the wort to break up the larger carbohydrates into simpler ones. They seem to have gotten around this for the Pale ale by using a lower starting gravity instead – less sugar in the beginning means that even though less is eaten, there is still less residual sugar at the end. A typical pale ale would start at a specific gravity of about 1.058 to 1.065, but the pale ale brewed by Hackett starts at only 1.050, which means that there is roughly a fifth less sugar dissolved in the wort at the start of fermentation.

As for those bottles they intend to roll out to the rest of the country…Cano has patented the yeast strain, and sequenced its genome so that he can enforce the patent. This would prevent unauthorized brewers from conjuring up cultures of the stuff from the dregs of these bottles (apparently Cano doesn’t intend to filter the product). I am ambivalent about this, because while I respect his right to protect his “babies” as he calls them, I’d like to see such a unique strain be as widely available as possible to further the cause of innovation and creativity with its use. However, I suppose this is where homebrewers come in to play; after all, Rogue’s patent on its PacMan yeast hasn’t stopped many a homebrewer from trying their hand with a sample.