…are women under represented in the history of yeast research because they don’t drink enough beer?

[The Leaven – exploring the relationship between science and religion (cont)]

Now, in the 21st cent, there are about 30 yeast factories in the European Union consuming about a million tons of cane molasses per annum. European yeast production alone generates an annual turnover of 800 million Euros. Until the turn of the 19th century yeast was supplied in a liquid form very similar to that found at the bottom of beer barrels. Perhaps, in a similar way to  how bread was made in early Egyptian civilisation from fermenting beer. Pliny the Elder noted in the first century BC that Gallic and Iberian bread was particularly light because it had been made with froth from the top of beer.

There are now several forms of yeast, compressed, crumbled and active/instant dried and genetically modified. The task of baking and brewing in earlier civilisations would have been difficult without the knowledge of sterilisation and pasteurisation. In ancient times, leaven or sourdough would have been left to rise in considerably unsterile conditions in a warm temperature. This environment would have been optimal not only for yeast but for all kinds of microbial growth including those that were pathogenic to humans. It is not surprising that leaven was associated with impurity and corruption. Excessive contamination would have certainly contributed to disease.

The desired characteristics of the yeast strain used in brewing and baking are different although they use the same species Saccharomyces cervisiae, which is also known as bakers or brewers yeast. Brewing yeast needs to have an agreeable flavour and an ability to flocculate so that the wort can settle quickly to achieve clear beer. In order to achieve these characteristics yeast are selected through generations, so that a specific yeast strain produces a desired flavour. In Darwinian terms this would be known  as directional selection.  So the variety of yeast varies with a particular industrial use. For instance, pizza dough is made with reduced power dry active yeast. Its slow fermentation allows the pizza to be shaped with reduced shrinkage after baking. Most commonly yeast for the baking industry is supplied as a compressed block because this form has a longer shelf life. Just 2.5 grams of this yeast in 100g of flour divides until it reaches a population size of 25 billion yeast cells.

Package of compressed yeast. Image by Hellahulla.

There is no question that yeast has transformed the structure of modern culture. In the food industry it provides baked goods, yeast extracts and alcoholic beverages. In scientific research it is a major model organism used mainly in molecular biology to discover information about the mechanisms of cellular processes. In fact, early in the 20th century, RNA was called yeast nucleic acid because it was first discovered in yeast.

Disappointingly, no women have been attributed to any of the early scientific discoveries associated with yeast. OK, they were less likely to encounter  Leeuwenhoek’s animalcule-containing sperm or beer during their daily routines but the reasons seem more likely to be associated with the status of women within religion.  As a consequence, they are largely excluded from early investigations were scientific endeavour was mainly to reveal the complexity of God’s creation. These investigations seem to be exclusively undertaken by men. Within the Bible it is clear that women were preferred to have a more subordinate role as revealed in a letter from Paul the Apostle to Timothy [Tim (1) 2, 11-15]:

Women should learn in silence and all humility. I do not allow them to teach or have authority over men; they must keep quiet. For Adam was created first, and then Eve. And it was not Adam who was deceived; it was the women who was deceived and broke God’s law.

In subsequent chapters, I will be addressing the portrayal of women in the progress of religion and science.

…big bang, creation and other theories

[The Leaven –  exploring the relationship between science and religion (cont)]

Leaven, the term commonly found in the English translation of the Bible, is often used to describe fermented dough or sourdough. It’s called sourdough because, along with yeast cells, it contained acidifying bacteria that produce lactic and acetic acid, giving the bread a unique tangy flavour. It’s believed natural microbial contaminants of milled grains and fruit were probably used for alcohol production and leavening in the Biblical era. This microbial flora would have included wild yeasts that were associated with cultivated crops. In just 100 grams of flour there are 1 to 10 billion microbes of these about 30,000 are natural yeast.

The historical steps taken to elucidate the metabolic processes and characteristics associated with yeast and fermentation follow an intriguing journey of scientific discovery that spanned nearly four centuries. A journey that commenced with the discovery of microscopy in the 17th century to the 21st century and  in to the complex science of molecular biology. This chapter looks at the history of Science in relation to the discovery of yeast, exploring how Biblical text has influenced the principles and directions of the scientific investigation. For instance, the Biblical version of Creation greatly differs from scientific theories of evolution. The ensuing debate this creates typically illustrates divides that exist between religious and scientific theory.

It’s generally accepted that for an enquiry to be viewed as scientific it must involve the gathering of observable, empirical and measurable evidence. The Scientific Method involves the collection of this data to formulate and test hypotheses. A number of proven hypotheses, from various published and recorded sources, can then be strung together in a wider context to form theories. The practice of distributing and therefore sharing data is often referred to as full disclosure; it permits evidence to be scrutinised by others thereby allowing the interpretation of results to be challenged.

The Bible suggests that a divine being must have in some way directed the creation of Life in order to account for its complexity. An understandable viewpoint as even a simple single-celled microscopic organism such as yeast is an intricate living structure encoded by over 6000 genes. It’s difficult to visualise that this could have happened gradually over time. The 21st century scientific method would not defend the concept of human origin as presented in the Bible as it’s largely based on theories without being supported by any tangible evidence. Though it may have  been defended when it was written, given the lack of scientific research at the time.

The Creation of Adam, Michelangelo c1511

Ultimately, it is impossible for anyone living in the 21st century to know, with any certainty, how the World was created without use of a time-machine.  Therefore, various scientific and theological arguments must be considered before determinate conclusions are reached.