Welcome to Spotlight Advanced. I'm Bruce Gulland and I'm Megan Nolette. Spotlight uses
a special English method of broadcasting. It is easier for people to understand no
matter where in the world they live. A man is in his kitchen.
His name is Samous Blackly. In front of him is a large flat wooden
board. Blackly covers the board in a special powder. It is a kind
of flower made from a grain called iron corn. This is one of the
oldest forms of wheat. Then he takes a large ball of dough from a
bowl. He begins to push and pull the dough, kneading it into a
round shape. The sweet smell of bread fills the room. Then, after
some time he places the dough in an earthen to Jean, and he puts
it into a hot place to bake. The dough begins to bake. Soon
it will be a large loaf of bread. But this is no ordinary bread.
Blackly is making the bread with ancient grains and ancient methods. But Blackly
is also using a special yeast. The yeast will make the bread rise or
expand. But this yeast is not the kind people normally use. This yeast
is also ancient. Using a special process. Blackly took the yeast from Egyptian
baking bowls. It is the same yeast used four thousand, five hundred years
ago. Yeast is one of the most important ingredients ever discovered. People use
it to make bread, alcoholic drinks, and fermented foods. People have been
using yeast for almost ten thousand years. Today's spotlight is on the history of
yeast. Yeast is not an ordinary ingredient like salt or pepper, or sugar
or flour. Yeast is a very small living organism. It is a kind
of fungus related to mushrooms. You cannot see it unless you look at it
through a microscope. Yeast feeds on sugars. When yeast eats these sugars,
it produces alcohol and carbon dioxide. This process is called fermentation. Carbon dioxide
is what causes bread to rise, and the alcohol gives bread its special flavor.
There are hundreds of different kinds of yeast are useful for making food,
but others do not work as well. One popular kind of yeast makes a
bread called sour dough. Sour dough has a special tart flavor. Other yeasts
make alcoholic beverages. Koji is a yeast used in Japan. The Japanese use
it to make a drink called sake. But there are even yeasts that people
do not use much. These are called wild yeasts. Humans first started using
yeast in food before people invented writing. Experts think the first use of yeast
was probably an accident. Wild yeast probably fell into a sweet drink and the
drink started to ferment. When people tasted it, they found it was good,
so they took some of the drink and used it to make more.
They were taking yeast and growing more, though they did not know it.
These were the first brewers. From this point, yeast began to change.
People began breeding the yeast. If they made something that they liked, they
would repeat the process, and they started breeding different yeasts for different things.
The yeast began to specialize. Kevin Vastrappen is a scientist at the University of
Leuven. He studies yeast genetics. He spoke to Science Daily about this process.
Sometimes early brewers had a very good fermentation. They were smart enough to
harvest the yeast. They used it to start the next batch, even if
they did not know what was in it. Reusing the yeast to make beer
separated it from nature. The yeasts were changing in the brewery, remember Shamus
Blackly from the beginning of this program. When Blackly started making his bread,
he was excited because of these changes. The Egyptian yeast was a lot like
sour dough bread. But what was yeast like almost five thousand years ago?
Blackly did not know what it would taste like. When he finally tasted his
bread, Blackly wrote on Twitter about his experience. The bread is light and
full of air, especially for a loaf made from these ingredients. The smell
and flavor are incredible. It is very different. You can easily tell the
difference even if you're not excited about bread. The first evidence of people using
yeast comes from China. The ancient Chinese made a drink called qui. They
used water, honey, rice, and fruit. Drinks made with yeast had
a lot of advantages. Of course, people liked the effects of alcohol,
but drinks made with yeast were also safer than water. In ancient times,
drinking water could be dangerous. It could make a person sick very easily,
but alcohol kills many of the diseases that live in water so you could drink
it without getting sick. Many civilizations used this to their advantage. In ancient
Greece, people mixed water with strong wine. This killed the bacteria in the
water, and because it was mixed, they could drink it most of the
day without being drunk. But making foods with yeast makes them more delicious and
healthier. These are fermented foods. The yeast breaks down sugars that may be
difficult to digest. Kafir is a fermented drink made from milk. It is
from eastern Europe. For most people, milk is very difficult to digest after
childhood. This is because of a sugar called lactose, which most people cannot
digest, but the yeast in kafir breaks lactose down. Because of this,
kaffir has almost no lactose in it. The yeast makes milk safe for people
who cannot drink milk. Many ancient people also used yeast to help in food
storage. Fermenting foods in this way is called pickling. Fermenting or pickling makes
food last longer, but it also changes the flavor. Kim is one of
the most famous pickled foods from Korea. Kimchi is fermented vegetables using cabbage and
radish. In ancient times, people made kimchi so that these vegetables would last
through the winter, But soon people began to make kimchi because they liked the
taste. Today we do not need yeast to clean water or to preserve food,
but over the years humans have developed a taste for fermented foods. We
eat them now because we like them. We continue to make them because they
are part of our traditions and they can connect us to people who lived thousands
of years ago. When he made his bread, Blackly wrote on Twitter,
this is very exciting. I am so amazed that it worked. It is
such a mudgical thing. We can share food in a rather genuine way with
our distant ancestors. Do you use yeast in your diet? What fermented foods
do you eat? Do you make any yourself? Tell us about it on
our website at www dot Spotlight English dot com. You can also find us
on YouTube, Facebook, Instagram, and Twitter. The writer of this program
was Dan Chrisman. The producer was Mitio Ozaki. The voices you heard were
from the United Kingdom and the United States. All quotes were adapted for this
program and voiced by Spotlight. This program is called Amazing Ancient Yeast. Visit
our website to download our free official app for Android and Apple devices. We
hope you can join us again for the next Spotlight program. Goodbye,