It’s now a pretty laboured joke within the beer industry that “brewers make wort, yeast makes beer.” Technically this is true, I do make sugar-water for a living, but I also nurture and care for a single-celled microorganism. My job is to coax yeast into behaving in a particular way for desired results - the production of alcohol, co2 and a measured amount of flavour compounds. If anything, my job is like looking after a Tamagotchi.
Yeast is fascinating. Like anything living, it has moods. It's already pretty peeved with having to produce ethanol when fermenting in the absence of oxygen (it would much rather metabolise sugars out in the open). Piss it off further and it will excrete all sorts of undesirable flavours into your beer. That pervasive butterscotch (diacetyl) taste in your IPA? Well you used all the hot water up and poor Saccharomyces has had to jump out of the shower mid-clean. Plonker. Why's there banana (isoamyl acetate) in my bitter? It's 30 degrees Celsius, your air con isn't working and now they're fuming. Sort it out.
‘Yeasts that make beer hazy, dry and citrusy.’
This is simply managing your temperatures and fermentation times correctly. Yeast produces those bananary esters when it ferments too warm, while it re-consumes those butterscotch compounds if it's left to clean itself following the main stages of fermentation. With certain beer styles these flavours are desirable in small doses, and a particular strain of yeast will produce them better than others. Belgian beer, for instance, is famously yeast-driven, be it an estery blonde or phenolic saison. At Anspach & Hobday we use French Saison and Bastogne Belgian Ale respectively when replicating these styles.
There are also yeasts that make beer hazy, some that make beer dry and others that give off citrusy flavours; there are strains that accentuate malts, cleaner varieties that prefer to stay neutral, types that enjoy cold temperatures and a few that can tolerate warm ones. And then there are wild yeasts, which are a whole other kettle of sour. So before we’ve even mentioned the word “hop” when building our beer, we have a plethora of tiny fungi vying for our attention, each with wonderfully idiosyncratic ways of expressing themselves. If you’re lucky some big breweries might let you in on their recipes, but they’re not letting you touch their house yeast.
There is one strain of yeast, however, that is both accessible to all and can seemingly do anything: Safale US-05, also known as “Chico” or California Ale yeast. It’s categorised as an American ale yeast and we use it in a lot of our beers. It might not have the je ne sais quoi of some continental strains, but where others may falter under pressure (literally), or freak out at the wrong temperatures, US-05 ferments away. In other words, if I make a mistake, ‘05 has me covered.
US-05 is at once clean and reliable, but also versatile and distinct. You could attempt most beer styles with it and be pleasantly surprised by the results. Ferment with ‘05 below 18°C and your pale ale might even taste like apricot or peaches, owing to an ester called linalyl formate. Or, if you’re our lead brewer, Daniel, manage to ferment a beer at 4°C and be happy you have anything to drink at all. Cheeky.
‘No two batches should be the same.’
So it’s a microbial Jack of all trades, master of none I hear you say. Not quite. It’s actually unique. Most brewer’s yeasts have multiple sets of 16 chromosomes (polyploids), or an abnormal number of chromosomes in a cell (aneuploid). US-05 has two sets of 16 (diploid). This means it’s more likely to mutate with each generation. So continue repitching it into fresh wort and no two batches should be the same.
The likelihood is that you know all this. What self-respecting beer enthusiast doesn’t know their yeasts, especially one as ubiquitous as US-05? Fine. I’ll tell you what you don’t know, though. Where on Earth it comes from.
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My role at Anspach & Hobday is twofold; I make beer alongside Daniel (“Dagga”) and Co-founder Paul (“Paulie Pops”). I also do a bit of beer related research on the side, finally putting my BA in History to questionably good use. Every Tuesday is #beerhistorytuesday, where I consult the annals of alcoholic history for tipply tidbits to tweet.
Understandably we’ve had to put this on the back burner considering current events (*cough*, Corona, *cough*). I did, however, previously ask Daniel where he thought US-05 came from for a potential post. "It's got something to do with Sierra Nevada," a Dan-sounding kettle replied. He poked his head out and added with a gasp of fresh air, "I'm not entirely sure though." That sounded concrete enough. I didn't follow up on it at the time, but now that I have nothing but time and I'm a touch microbially-minded I thought I'd look into it.
‘This they called “Chico”’
This is how the story goes: Sometime in the late 1970s or early ‘80s, California based brewery Sierra Nevada was given a yeast strain by Ballantine brewery of Ballantine IPA fame. This they called "Chico" named after their brewery’s hometown. That's it.
Pardon?
“Well, where did Ballantine get it?” you might ask. And ask you should. No one seems to know. I’ve perused multiple forums of others similarly perplexed and the best I can find is that someone knows someone who heard through the hop-bine that it’s a British strain. Supposedly Ballantine employed a Scottish brewmaster in the 1930s, who brought it with them. That sounds likely enough, except there’s no record of this, at least that I can find. Also Ballantine’s founder, Peter Ballantine, was himself Scottish - could this not be him?
Anyway, none of this matters as Ballantine’s recipes have long since been lost, while the company has passed through so many hands over the years crucial documents have either been destroyed or they’re collecting dust somewhere. Beer and posterity really don’t like each other. The Pabst Brewing Company has owned the Ballantine brand since the 1980s. In 2015 their head brewer attempted to reconstruct Ballantine IPA. They did it completely by taste (http://allaboutbeer.com/ballantine-ipa/). It’s a sad irony, but I bet they used US-05. I reached out to Pabst to see if they could shed any light on this mystery, but they didn’t get back to me.
‘How do you misplace a yeast strain?’
How do you misplace a yeast strain? Wild, microscopic yeast can float around merrily doing what it wants, but a preserved culture? Come on. I needed answers like a 1970s pub needed carpets. There was, however, one forum post dated back to 2009 that caught my attention. It’s a Sierra Nevada employee answering a question similar to my own by somebody called Whorst (whorst name ever). It reads:
“Whorst,
Wow, great question [cheers].
I had to actually ask Ken Grossman [Sierra Nevada cofounder] as I only know that our yeast originally came from Siebel Institute out of Chicago. Ken stated that the origins of the yeast are thought to come out of England. It is true that a variation of this yeast was used by several breweries in the early 1900s, one being the Ballantine Brewery.
Hope this helps,
Terence.”
Terence, it most certainly does! Bit of a vague email, though. Do you mean Sierra Nevada’s Chico strain of yeast wasn’t passed on by Ballantine, but by this Siebel Institute, or that it still originates with Ballantine, but stopped off in Chicago first? Also, it’s English, not Scottish? While you’re there, why does the yeast behave a bit like German strains - cool fermenting, extremely clean, efficient as always - not traditional, frequent tea-break English ale yeasts?
These were questions I decided to ask the Siebel Institute of Technology, a school dedicated to the brewing sciences nestled in the “Vibrant West Loop/Greektown area” of Chicago. Over the years its faculties have moved around the city like an alternative student trying to find their lunchtime table. I must have caught them off guard as I was promptly redirected:
"Hi Ben,
There was a study led by Maitreya Dunham from Washington University on this particular subject, it would be best for you to contact her directly.”
And off they scuttled. No mention of Chico, Sierra Nevada or their procurement of the strain, but the shivers down my spine told me I was finally getting somewhere. If this Maitreya Dunham couldn’t settle things for me I was happy to call last orders.
Maitreya is a professor at Washington University specialising in genome evolution and copy number variation in yeast. She’s also the co-founder of Phase Genomics, which is some sort of genome software/technology company - the website was reassuringly wordy, making me think I’d come to the right place. Her already busy studies into one thing microscopic had been burdened by another as of late. “Sorry,” she opened via email, “I’m in the middle of moving my giant intro genetics class online and [I’m] a little overwhelmed. I’ll be in touch soon.” As a friend of mine once said, “if you want something done, give it to a busy person.”
Well, he was full of it. She never did get back to me. Gutted. To be fair, my timing was abysmal and she had better things to be doing. It’s a shame though, what a narrative it might have been; Maitreya, through years of education and specialist training isolates the genus culture of US-05. She then hurriedly writes up her findings and contacts me, a brewer with two and a half years experience and too much time on his hands:
“Ben!”
“Yes Maitreya?”
“I’ve done it.”
“You haven’t!”
“You bet I have. Guess where it is?”
“Where Maitreya, where!?”
“Right, US-05 is identical to a strain we've located at Last Piece Brewery.”
“Last Piece Brewery? I haven’t heard of them, where are they?”
“They’re in Jigsaw, Puzzleshire, just on the England/Scotland border. The founder was German.”
“Of course! It all fits together perfectly!”
And off I set, three sheets to the wind, on my pilgrimage to the birthplace of US-05. My story goes viral and I’m asked to accept an award at the annual Singe-Cell-abrations in Saccharomento, California, for publishing someone else’s scientific breakthrough. Case closed.
Or as Carmen at the National Collection of Yeast Cultures (NCYC) in Norwich politely informed me:
“Strain[s] in continuous propagation would have experienced natural mutations […] so it will be difficult to trace after so many years of use by breweries.”
‘The answers rested with Ballantine.’
Really, all Maitreya could have told me is more about the strain, and maybe some qualities it shares with others. Finding the source was less a scientific question, and instead an historical one. The answers ultimately rested with Ballantine.
Funnily enough, as I was double-checking some embarrassing mistakes of mine corrected in Carmen’s above email (which I may have omitted) I stumbled across a blog post. It's from 2015 and written by the all too perfectly named “YeastWhisperer." It offers as much resolution as I think we’re going to get on the matter.
In a nutshell, the Siebel Institute’s “BRY 96” is the parent culture of US-05. They did indeed acquire this strain from Ballantine. What is interesting is that BRY 96 was used to make Ballantine’s lagers, not ales, which explains why it can tolerate cold temperatures. "BRY 97", on the other hand, was used to make Ballantine's ales. This is what yeast manufacturers, Lallemand, market as their West Coast Ale strain.
Old mate YeastWhisperer also found a deposit left with the NCYC from 1973 of an Irish yeast that was used to make lagers. It was also 100% an ale strain, like '05. YeastWhisp concludes that this was quite common in the past - breweries using ale strains in lagers - and that this was just one example of many. Or maybe, just maybe, US-05 is Irish? Stop it, Ben.
If you are an ex Ballantine employee, or YeastWhisperer, and know more about the origins of US-05, Ben is dying to hear from you. Send him a message at ben@anspachandhobday.com