Have you ever heard about yeast?

Whether you work in the field of biology or just like standing in the kitchen from time to time, you have probably heard about Saccharomyces cerevisiae. Ok, maybe you don't go looking for that name in the supermarket when trying to bake cinnamon rolls, but you will encounter the more commonly used names: baker’s yeast or brewer’s yeast. Whatever you call it, its astounding usages and impressive biology have fascinated humans for thousands of years. Long before anyone knew what it was, yeast shaped the history of bread, beer, wine and more.

A brief history of yeast

For centuries, people relied on the mysterious process of fermentation without understanding the role or existence of yeast. Bread dough was simply left outside to capture wild yeast from the air, or bakers saved a piece as a starter from previously fermented dough. Over generations, this practice led to the selection of yeast strains particularly suited for baking and brewing without even knowing about yeast or other microorganisms. It was not until the 17th century, when Antonie van Leeuwenhoek first observed yeast under his single-lens microscope. Nevertheless, yeast was long thought to be a chemical agent rather than a living organism. This changed in the 19th century, when Louis Pasteur demonstrated that fermentation was a biological process carried out by living organisms

Fermentation pathway

Advances in microbiology in the late 19th and early 20th century allowed the isolation and mass production of pure yeast strains. This innovation not only transformed the industrial production of bread and beer but also modern biology.

Yeast in the modern world

In the modern world, S. cerevisiae is not only crucial in food production but also in biotechnology and synthetic biology. It serves as a model organism for studying core biological processes. And yet, yeast remains essential not only in biotechnology but also in brewing and especially in baking. To celebrate this remarkable microorganism, we have gathered a few safe “protocols” for some (tasty) experiments. You can perform all of them in your own lab (your kitchen). All kitchen-friendly and without the need of a BSL-1 workspace ;)

Guten Appetit!

Basic Yeast Dough

Ingredients for Simple Yeast Dough

500 g flour
20 g yeast
50 g sugar
1 pinch of salt
approx. ¼ L milk
50 g butter or margarine

Ingredients for Fine Yeast Dough

500 g flour
30 g yeast
75–100 g sugar
1 pinch of salt
⅛–¼ L milk or cream
80–125 g butter
1 whole egg, 1–2 egg yolks
Optional flavourings: lemon zest, vanilla, rum

Instructions

Make a well in the sifted flour and add the crumbled yeast into it.Mix the yeast with 1 teaspoon of sugar and some lukewarm milk, incorporating a little flour from the sides of the well, to form a thick starter (called Dämpferl).

Cover and let rise in a warm place for about ½ hour · Sprinkle the remaining sugar, salt, and flavoring ingredients over the flour. Warm the rest of the milk together with the butter and pour it, lukewarm, over the flour. Finally, add the eggs.

Beat the dough vigorously until it shows bubbles and comes away smoothly from the sides of the bowl. Cover and let it rise in a warm place for about 1 ½ hours, until the dough has doubled in size.

Now place the dough onto a floured board, shape it into the desired pastries or loaves, and cover with a cloth. Allow it to rise for a third time in a warm place covered with a cloth before placing it into the preheated oven to bake.

You can shape the finished dough into any shape you want or use it as a base for the other sweet treats below.

Reference: Stuber, Hedwig Maria. 1961. Ich helf dir kochen. 4th revised edition. Munich/Bonn/Vienna: BLV Verlagsgesellschaft.

Plum Pie

Ingredients – Yeast Dough

250 g flour
100 g lukewarm milk
10 g fresh yeast
40 g sugar
1 pinch salt
1 pinch ground vanilla
1 small egg
40 g soft butter

Ingredients – Topping

2 tbsp brown sugar
1 tsp cinnamon
1 kg plums

Instructions

Put the flour into a bowl and make a well in the center. Dissolve the yeast in the lukewarm milk, stir in 1 tbsp sugar, and pour the mixture into the flour well. Mix the yeast milk with a little flour, cover the bowl with a kitchen towel, and let the starter dough rest for 10 minutes.

Add the remaining sugar, vanilla, salt, and egg. Knead the dough in a stand mixer at low speed for 10 minutes. Then add the soft butter and knead at medium speed for another 5–10 minutes, until the dough comes away from the sides of the bowl.

Cover the bowl again with a kitchen towel and let the dough rise in a warm place for 1 hour, until it has doubled in volume.

Meanwhile, wash the plums, cut them in half, and remove the pits. Carefully make a cut lengthwise in each half without cutting all the way tbrough.

Briefly knead the risen dough again, then roll it out into a circle about 30 cm in diameter. Place it in a pizza pan lined with baking paper or on a baking sheet. Mix the brown sugar with the cinnamon and sprinkle evenly over the dough. Arrange the prepared plums in a fan shape on top. Let the cake rise one last time at room temperature for 20 minutes.

Meanwhile, preheat the oven to 190°C (top and bottom heat). Bake the cake on the middle rack for 35–45 minutes.

Serve with softly whipped cream.

“Buchteln” – Sweet Yeast Dumplings

Ingredients

375 g wheat flour
30 g fresh yeast
120 ml lukewarm milk
1 tsp sugar
75 g soft butter
60 g sugar
2 medium eggs
1 pinch salt
¼ tsp lemon zest (optional)

Instructions

Crumble the yeast into a cup with the lukewarm milk. Add 1 teaspoon sugar and stir with a spoon until dissolved.

Put the flour in a bowl and press a well into the center. Pour the lukewarm yeast-milk mixture into the well. Mix with a little flour from the sides and let stand in a warm place for 10 minutes.

Add the eggs, soft butter, remaining sugar, and salt, and mix everything together. Knead the dough in a stand mixer for a few minutes. Cover the bowl with a cloth and let the dough rise in a warm place for about 45–60 minutes.

Grease a baking dish (about 20 × 20 cm; alternatively, use a springform or loaf pan) with butter and sprinkle lightly with sugar. On a floured work surface, shape the dough into 2 long ropes. Cut each into 6 pieces (12 total), then roll each piece into a ball with your hands. Place the dough balls into the prepared pan with some space between them. Cover again and let rise for another 20–30 minutes.

Preheat the oven to 180°C (top and bottom heat). Bake the Buchteln for 20–25 minutes until light golden brown. While still warm, dust with powdered sugar and enjoy. They taste especially good with vanilla sauce or fruit compote.

Cinnamon Rolls (Royce)

Ingredients – Dough

270 ml milk
60 g butter
500 g flour
50 g sugar
1 packet vanilla sugar
1 pinch salt
½ cube fresh yeast
Butter for greasing

Ingredients – Filling

100 g soft butter
70 g sugar
2–3 tsp cinnamon

Ingredients – Glaze

70 g cream cheese
1 tbsp soft butter
1 heaping tbsp powdered sugar

Instructions

Heat the milk with the butter in a pot, letting the butter melt.In a bowl, mix the flour with the sugar, vanilla sugar, and salt. Crumble in the yeast. Add the lukewarm milk and knead with the dough hooks for 5 minutes until a smooth dough forms.

Let it rest, covered, for 45 minutes.Grease a round baking dish (Ø 30 cm). Knead the dough on a lightly floured work surface and roll it out into a rectangle (about 40 × 30 cm).

For the filling, beat the soft butter, then add the sugar and cinnamon. Spread the cinnamon butter thinly over the rectangle, leaving a border of about 1 cm. Roll it up from the long side. Cut into 10 slices with a sharp knife.Place the individual slices into the baking dish. Let rest, covered, for 30 minutes.

Preheat the oven to 180°C (fan: 160°C). Bake for about 25 minutes. Let the cinnamon rolls cool slightly.

For the glaze, beat all ingredients together and spread thinly over the lukewarm cinnamon rolls.

Best served immediately. The recipe makes about 10 rolls.

Pizza Dough

Ingredients

500 g wheat flour
300 ml water
2 tsp salt
5 g fresh yeast

Instructions

First, sift the flour together with the salt and place it into a dough mixer or a bread machine with a dough function. Dissolve the yeast in the lukewarm water and then add it to the flour-salt mixture.

Knead the ingredients for 20 (!) minutes into an elastic, homogeneous dough. Note: An electric mixer is almost essential here; if necessary, a hand mixer with dough hooks will also work.

After kneading, cover the dough with a damp cloth and let it rest for two hours. Then divide it into four pieces of about 200 g each, shape them into balls, and let them rise, covered, for another six hours.

Yeast Goes Wild

And if you don’t like your yeast domesticated, you can also make use of wild yeasts. Yeast fermented foods and drinks are good for gut health and you don’t even need to buy yeast. Just use the ones tht are already on your ingredients (because yeast is everywhere).

Ginger Bug

Ingredients

20–30 g organic ginger
25 g sugar
300 ml water

Instructions

Wash about 20-30 g of organic ginger and grate it with the peel. Stir the grated ginger, 2 tablespoons of sugar (about 25 g), and 300 ml of water in a large jar (at least 450 ml). Cover with a paper towel or a cloth and secure it with a rubber band.

Let the mixture sit for about a week at room temperature. Add about 10 g grated ginger and 1 tablespoon of sugar everyday. The ginger bug is ready when the surface foams up and the liquid sizzles when shaken. Now you can store it in the fridge and feed it with a bit of grated ginger and a tablespoon of sugar every week. If the flavour gets too intense, just add some water to it.

You now have a nice and healthy supplement for juices or other beverages that gives them a nice little punch. Enjoy!