The Yeast of my Troubles… part 2

The same bed of yeast may be cultured from batch to batch in an effort to modify the yeast to recognize and react to the ingredients of a particular recipe. In this rudimentary culturing process, the yeast evolves with each new batch, producing predictable qualities in the finished beverage. The medieval brewer facilitated this by scraping the foam layer from a currently fermenting batch or by setting aside the lees from the fermenter in order to use it to ‘start’ the next batch.

When flowers and other leafy herbs or fruits were added to the brew it almost certainly provided necessary yeasts; for yeast, as such, was not an ingredient of itself. The people of the Middle Ages knew that yeast was necessary but didn’t quite understand where it came from. The barm (yeast froth) was scraped off the top of the fermenting beer, saved and used to make bread or promote the next batch of brew.[1]

Some brewers did, it seems, recognize the possible infection of their brews by airborne yeast, a situation first mentioned at Munich in 1551. The realization was slow in coming, however. As early as the mid-fourteenth century a Flemish recipe book mentions adding yeast to beer, and it seems likely that already by 1300 brewers were using some of the foam skimmed off the top of the fermenting beer of the last brew to start fermentation with the next one. By the sixteenth century, brewers commonly added yeast to wort from cultures which they kept separate and which they controlled and maintained. Regulations in Harlem in 1519 and 1550 leave no doubt that brewers added yeast once the wort was in the fermenting troughs.[2]

The greatest example of culturing yeast from batch to batch comes to us from the Trappist breweries of Belgium. Of the modernly remaining ten Trappist abbeys that produce beer, two date to our period: The Brasserie d’Orval in the Gaume region of Belgium, and the Abbey of Notre Dame de Saint-Remy near Rochefort. The Rochefort beers have been brewed with the same strains of yeast being cultured forward batch-to-batch since 1595.[3] Although the current Orval brewing facility only dates to 1931, the original brewery dates back to at least 1628, based on writings from the abbot at the time.[4]


[1] Westerson

[2] Unger, pg. 152

[3] Fourneau

[4] Saint Peters List


Fourneau, Auguste (2006). L’abbaye Notre-Dame de Saint-Remy à Rochefort. Histoire d’une communauté cistercienne en terre de Famenne, 2nd edition. Abbey of Saint-Remy.

Saint Peters List (2013). “The Ten Authentic Trappist Monk Beers”. History / Life & Leisure. Retrieved 11 February 2015, from

Unger, Richard W. (2007). Beer in the Middle Ages and the Renaissance. University of Philadelphia: Pennsylvania Press.

Westerson, Jerry (April 1998). “Searching for Medieval Ale”. Brew Your Own.

The Yeast of my Troubles… part 1

Although yeast as a microbe was not known until the early 19th century, yeast itself was known earlier than the days of the Roman empire. Recognized as both the froth that rose to the top of the fermenting vat and the sludge that fell to the bottom, its cause may not have been well known but its effect was certainly common knowledge among both brewers and bakers.

The traditions of brewing were carried on and thrived under the Roman Catholic Church. Nearly every major monastery in medieval Europe contained a brewery that served not only the monks but also pilgrims and the surrounding villages (perhaps as an inducement for attending mass). One large monastery in Switzerland had three breweries, each adjacent to a bakery. Brewing and baking, in fact, were closely related activities in ancient and medieval times.[1]

The presence of a fermenting agent was known in France in the 13th century. In a comprehensive law enacted by Louis IX in 1268, he laid out numerous strictures to ensure the quality of fermented beverages, including the sale of yeast barm. “No beer yeast shall be hawked about the streets, but shall be all sold in the brew-houses to bakers and pastry cooks, and to no others. Beer yeast brought by foreigners shall be inspected by a jury before it is exposed to sale.”[2]

Spontaneous fermentation was undoubtedly the result of natural yeasts found in the atmosphere, or exigent on the leaves and skins of various ingredients added to provide flavor. Dominant strains of wild yeast in any locale would have been the primary means by which yeast made it into the fermenting vessel.[3] Wild yeasts by their very nature are aggressive, highly tolerant of a hostile brewing environment (able to survive in more extreme temperatures or in a high-alcohol beverage), and more likely to produce what we would today call ‘off flavors’.

Spontaneous fermentation—what I am hereby referring to as nothing short of “immaculate”—is an age-old practice, first by accident and then by intention, that truly puts Mother Nature at the helm of brewing magic. This type of fermentation takes place when ales are fermented with wild yeasts—from an open window, for instance, or already residing in a barrel…[4]

Before the advent of refrigeration and advances in the science of fermentation in the mid-nineteenth century, almost all beer was, to varying degrees, sour. The culprits were pre-modern sanitation and poorly understood, often naturally occurring bacteria including Lactobacillus and Pediococcus, as well as Brettanomyces yeasts, which can contribute a hint of tartness and characteristic ‘funky’ flavors and aromas, sometimes compared to leather, smoke, and ‘horse blanket.’[5]

Relying on airborne yeasts, brewers virtually never got a distinctly high or low fermentation variety but rather something mixed. The method worked but was haphazard and raised the risk of infection from unwanted yeast strains which could ruin the beer.[6]



[1] Kiefer

[2] Salem, pg. 19

[3] Meade

[4] Herz

[5] DeBenedetti

[6] Unger, pg. 152


DeBenedetti, Christian (26 July 2013). “A Brief History of Sour Beer”. The New Yorker.

Herz, Julia (n.d.) “Spontaneous Fermentation: Science, Not Sorcery”. Craft Beer Muses. Retrieved 17 January 2015, from

Kiefer, David M. (2001). “Brewing: A Legacy of Ancient Times”. Today’s Chemist at Work. American Chemical Society.

Meade, Ronan (n.d.) “Yeast Research Project Documentation”. Retrieved 15 January 2015, from

Salem, Frederick W. (1880). Beer: Its History and Its Economic Value as a National Beverage. Hartford: F. W. Salem and Co.

Unger, Richard W. (2007). Beer in the Middle Ages and the Renaissance. University of Philadelphia: Pennsylvania Press.

The longest journey begins with a single step –Lao Tzu

I haven’t really taken the time to consolidate my various endeavors in a single location. This blog is one such attempt.

My name is Madoc, and I make beer… and wine, and mead. I have been brewing since 1995, and specialize in historic brewing practices in conjunction with my participation in an international historical society known as the Society for Creative Anachronism, Inc.

My journey started with another member of the SCA, Ansel the Barrister, who is a Georgia lawyer working for the Department of Defense Logistics Agency. A home brewer of some reputation, I was over at his house once when he said in his classic southern drawl, “Madoc… as much as you like a good beer, I’m s’prised ya don’t brew yo’own.” I replied that I would love to, but that I didn’t understand organic chemistry. He gave me that look southern mamas give their children when they’ve said something stupid, and said, “Huh?” I replied that I had been led to understand that brewing involved a lot of organic chemistry. He took a big draught from his mug, and stated firmly, “I don’t know nuthin’ ’bout no organic chemistry… but you come over t’the house Sunday and I’ll teach ya ta make beer.”

That first batch of all-extract English bitter was all it took to get me hooked. My birthday present from my wife that year was a beginners brewing kit, and the rest is history. I moved from Georgia to Missouri in 1996, where I met Shandrake Vale and Alaric von Thurn, two other SCA members who were actively brewing. Shandrake eventually went on to other endeavors, and is now a beadmaking Laurel. Alaric and I took on the regional brewing community. We kick-started the old kingdom brewers guild, and instituted a kingdom brewing championship at Lilies War. We bought out a flailing brew supply business and grew it into an almost-successful retail and online outlet (that business was subsequently sold). Mostly, we brewed… and we brewed lots. We also read – books, papers, whatever we could get our hands on – anything to do with the historical aspects of brewing. This is where my thirst for research gained solid ground.

Once I retired from the military, I moved back to western PA where I was raised, and got active in the new SCA kingdom that had sprung up during my absence. While the brewing community was not as active or diverse as I had become accustomed to, there are still plenty of lively and exciting individuals with whom I have been able to share my passion. I now spend most of my brewing time advancing the concept of historical brewing within the Kingdom of Æthelmearc.

For several years since returning home, people have been asking me to post my research. I have been actively teaching classes, organizing competitions, providing demonstrations, and responding to nearly every request for donations of home brewed beverage… but aside from posting a few files on various web sites, I haven’t really taken the time to consolidate my various endeavors in a single location. This blog is one such attempt. It is my hope that historical brewers within the SCA, as well as those outside the organization with an interest in historical concepts of brewing, will find some of my musings useful, if not necessarily interesting. Please enjoy the site as you browse through it, and feel free to leave me feedback if you are so inclined.

Regards//Madoc Arundel (mka Christopher Miller)