Yeast
/jiːst/
nounB1
Definition
Yeast is a small, single-celled fungus that helps make bread rise by producing gas when it eats sugar. It is also used to make drinks like beer and wine by turning sugar into alcohol and bubbles.
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See It in Action
A fungus used in baking and brewing
- •The baker added yeast to the dough to make the bread rise.
- •Yeast ferments the sugar in grapes to produce wine.
- •Without yeast, the bread would be flat and hard.
The living organism itself
- •Yeast cells are very small and need sugar to grow.
- •Scientists study yeast to learn about cell functions.
Make It Stick
- ✓Think of "yeast" like "bacteria" (a simple A1 word for tiny living things), but yeast is a fungus that helps food and drinks change.
- ✓Picture tiny invisible bubbles growing in bread dough, making it soft and big.
- ✓It's the feeling of fresh bread rising in the oven, warm and soft.
- ✓Sounds like "yeast" → imagine a tiny beast (monster) inside bread making it grow bigger.
- ✓Remember the smell of fresh bread or the fizz of soda—both happen because of yeast working quietly.
- ✓NOT like "salt" (a simple ingredient that does not change food), yeast actually causes food to change by making gas and alcohol.
- ✓NOT like "mold" (a fungus that spoils food), yeast is helpful and used on purpose.
- ✓NOT like "bacteria" (some cause sickness), yeast is mostly good and used in cooking and drinks.
Try Other Words
- •Baker’s yeast: a common type of yeast used in bread making (Use when specifically talking about baking)
- •Leaven: a substance that makes dough rise (Use in baking contexts, more general term)
- •Ferment: the process yeast causes to turn sugar into gas or alcohol (Use when focusing on the action yeast does)
Unboxing
- •Word parts: "yeast" is a single root word with no prefix or suffix
- •Etymology: Old English "gist" or "yeast," meaning foam or froth from fermentation
- •Historical development: Used since ancient times for making bread and alcoholic drinks
- •Modern usage: Commonly refers to the living fungus used in baking and brewing today
- •Interesting fact: Yeast was one of the first microbes humans learned to use for food and drink
Reflect & Connect
•How does yeast change the way we eat and drink in daily life?
•What would happen if we tried to bake bread without yeast or a similar rising agent?
Fill in the blanks
1.Yeast helps bread dough ___ by producing gas when it eats sugar.
2.When making beer, yeast ferments sugar to create ___ and alcohol.
3.Unlike salt or sugar, yeast is a ___ organism that changes food.
4.Yeast causes dough to rise, but if you add too much ___, the bread can taste bad.
5.The process where yeast turns sugar into gas is called ___.
6.Yeast is different from mold because yeast is ___ and used in food.
7.To make bread soft and fluffy, bakers usually add ___ to the dough before baking.