Monday, July 16, 2012

Yeast Geography?

I was listening to one of the old 'Food Programmes' on BBC Radio 4 about the history of yeast when it occurred to me that I had never heard anything about the relationship between modern brewing yeasts and geography. Like, whether or not the flavor characteristics of an individual brewing yeast are partly determined by their place of origin, or instead, are they due to a controlled manipulation of the yeast over the course of many generations, regardless of place?

The idea of something having a flavor unique to a particular place is nothing we've not heard about. The French have been using the term "terroir" to justify the high prices and supposed quality of their wines for decades, just as the farmer at your local market will say his fruits and vegetables are unique to the land he/she grew them. And in the brewing world, such an idea is equally as common. We are so often told that the lambics and sours beers of Belgium are especially unique because they contain microflora only found in that particular part of the world. As such, a brewer in Brooklyn cannot make the same lambics as those found in Brussels, just as the Cascade hops growing in my backyard will not taste the same as those grown in Oregon. Place of origin is important. 

But does this even apply to our modern Saccharomyces cerevisiae brewing yeasts?

As beer drinkers, we are often told by brewers that it is their own yeast and fermentation process that makes their beers so special. Here on the East Coast, Alan Pugsley introduced the idea of brewing beer with Ringwood, a yeast that imparts its own distinct character to the beer and changes overtime with the brewery. Across the pond, my first visit to a traditional English brewery involved a short lecture on their house yeast and why it is unique to where they are located. And while I've not been to Sam Smith's brewery or ever visited Yorkshire, I do know enough to never insinuate that their yeast and/or process is anything but superior to those used in the South. It is somewhat romantic to think that some beers taste the way they do because of where they come from.                                                                                                                                                                                                                                                 While it is nice to think that 'place of origin' is indeed important with brewing yeast, history seems to say otherwise. Apparently, some of the biggest Scottish breweries used any yeast they could get their hands on. Ferment a batch of beer with one yeast on Monday and come Tuesday use something else. It makes no difference?! Big breweries often sold their yeast to smaller ones or used a different yeast if it suited their needs. No one seemed to say, "hey, this new yeast doesn't have that 'local' flavor!" Or, maybe the idea of yeast imparting flavor to a beer wasn't important back then... it's not like the historical records are full of 19th century beer snobs listing all the flavors found in their beer, let alone mention much of anything about the yeasts they were brewing with. 

In an attempt to get a better idea of where my favorite English yeasts come from, or at least where they were once used, I made this basic map. Admittedly, I was initially tempted to make sweeping assumptions about why these yeasts are well suited to the areas where they were once brewed. Like, how Northern yeasts make malty and rich beers that are well suited for topcropping and cool fermentation in stone... while those found in the Midlands around Burton upon Trent are dry and minerally... and the South's are clean, soft, and suited for high hopping. Of course, this is all a load of fantasy. Who knows where these yeasts actually originated or where they were first used, and how distinct they are genetically. Yeast are capable of changing character so quickly, it wouldn't take very long for a yeast born in London to mutate into something completely different when used in Manchester.                                                                                                                                                                                                                 Back to my original question. I still have no idea whether place of origin has anything to do with yeast character or flavor. I would like to think it does, in that when I brew a bitter with the Fullers yeast, that I'll be making something akin to what the brewery was making so many years ago. In truth, I highly doubt much of the English yeasts we use today are even remotely similar to those used in the not so far past. Nowadays, almost all brewery yeasts are pure cultures (with a few notable exceptions) and bacteria and other organisms are no longer tolerated in our modern breweries. It is shame too, since I bet many of those mixed culture beers were quite unique tasting. Regardless, it would be nice to see an attempt by the yeast manufactures to at least try and provide a bit more information about the yeasts they sell; where it came from, how was it fermented (Burton Union, Yorkshire Square, ect...), and so forth. 

1 comment:

  1. Apologies for resurrecting an old post but I’ve only recently found this excellent blog and I’m working my way through the back catalogue.

    I've recently been considering terroir and beer myself. I came to a couple of conclusions whilst supping last of my first AG batch.
    1. Terroir is particularly important to wine as it uses fewer ingredients. The flavour of the grapes is very much dependant on the local environment and the yeast is obviously local too (having grown on the grapes themselves). Compared with beer; to not only consider the variety of malt/hop/yeast used, but to also consider the locality of each would be introducing a level of complexity that I don't think even the most sensitive palates could detect (especially true when multiple malts/hops are used!). I will admit that from the forums I read people do notice a difference between hops (e.g. American cascade vs British cascade) so perhaps it’s just my taste buds that are deficient!
    2. The environment a vine/bine/row of barley is grown in is unlikely to change even over several decades (year to year variations due to weather i.e. vintage is an entirely different discussion...), whereas yeast changes from generation to generation in a matter of days/weeks. The effect of time on a yeast's character (unless properly controlled) would be far greater than geographical location I believe.

    Perhaps rather than looking for a geographic location of origin we should ask for the brewery it originated in. White Labs etc haven’t been around forever  That would perhaps give us a clue as to the style of beer it was used to produced, how its evolved over time (assuming the brewery uses the same strain) and the particular characteristics it imparts to the Beer of that region.

    After all, the term terroir is applied to the finished wine and not to a particular grape variety.


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