What is Yeast?

What is Yeast?

I love bread.

I love to make bread.  

I love to smell baking bread.  

And, I love to eat bread…especially when it is still hot from the oven.

In fact, I love bread so much I make at least one loaf of bread every Sunday afternoon.

And….I love bread so much that I have taught community bread making classes for a local university.  

When I teach those classes one of the most commonly asked questions is: What is yeast? 

So today as I was mixing up some bread I decided to put together a quick post about what yeast is, how it works, how to store it, and a few other quick facts. So let’s get started.

Yeast, What is it?

Yeast are actually single celled fungi.  The scientific name for the yeast that baker’s use is Saccharomyces Cerevisiae which means “sugar-eating fungus”.  Yeast cells digest food to get energy for growth…it’s favorite food is sugar.  Yeast converts these carbohydrates into carbon dioxide which forms tiny bubbles in the dough…this causes the dough to rise. Once the bread is cooked the yeast dies but the dough is set and retains its larger size.

How to Buy Yeast:

Individual Packets, Jars, “Bricks”, or cakes

How to Store Yeast:

Store any unopened packages/jars in a cool, dry place.  Once a yeast container has been opened it should be stored in an airtight container in a refrigerator or freezer.  Opened yeast can be frozen for up to 6 months and refrigerated for up to 4 months.  Yeast has an expiration date that is on each container…it is two years from the date it was packaged…because yeast is a living organism this is fairly accurate.

What is “proofing”:

Proofing (sometimes called “proving”) is testing your yeast to make sure it is still alive…the most common way is to add dry yeast to warm water with a sugar and waiting 2-5 minutes to see if it “blooms” or “blossoms”.

Blooming looks like foam and bubbles.

Temperature:

For all the fantastic things that yeast can do, it is a fairly fragile fungi. The yeast, after being stored in a cool dry place needs to be awakened to get to work. It can only do this when given something to eat (sugar) and then warmed up.

The optimal water temperature for yeast is right around 95 degrees Fahrenheit. But if the water warms up too much …over 120 degrees… the yeast will start to die…but if the water isn’t warm enough….under 70 degrees…the yeast will stay too sleepy and be slow to expand.

Nutritional Facts:

In 100 grams of yeast there are 62 calories and 9 grams of carbohydrates. Other than that….there isn’t much else…no protein, cholesterol, fat, sodium, etc. Only calories and carbohydrates.

Yeast is weird and cool and I could talk about it for a lot longer….but for today there is a fast and simple explanation of yeast.

If you would like to try out your new found knowledge of yeast by whipping up an easy french bread recipe you can check out THIS POST: Easy French Bread Recipe

Good Luck and Happy Baking!