Science Smarts: Root beer science

By Patty Rooks on November 1, 2025.

It is a special someone’s birthday today so I thought long and hard about what I should write about so I can dedicate this article to them! Well, one of the first times I met this person, and subsequently many times later on in the years, they would always order this beverage when we were out. I am not a pop drinker (yes, I am boring and usually drink water), so of course, it got me to thinking, how is this beverage actually made? Let’s get started!

*Remember to ask an adult before doing this experiment.

Materials

– Sugar

– Measuring cups

– Measuring spoons

– Root beer extract

– Yeast

– Empty 2L soda bottle

– Funnel

– Water (preferably distilled)

– Permanent marker

– Towel

Procedure

1. Make sure that the 2L bottle is clean. Personally, I like to sterilize my equipment that I will be using in boiling hot water. It is essential to have clean materials as any foreign substances (such as bacteria) will destroy your whole batch of Root Beer.

2. Place the funnel in the bottle.

3. Measure one cup (250 mL) of sugar and pour it into the bottle.

4. Add ¼ teaspoon (1.25 mL) of yeast and add it to the sugar.

5. Fill the bottle 3/4 full of water. Leave a little bit of space at the top.

6. Measure and add one tablespoon (15 mL) of Root Beer extract to the bottle.

7. Using the permanent marker, place a mark on the bottle where the water is filled up to.

8. Place the cap on TIGHTLY (do not make this mistake!). Mix, shake and mix some more.

9. Set the bottle aside for three or four days covered with a towel. You want it to be kept at room temperature.

10. Check the bottle every day. Give it a GENTLE squeeze. If it feels hard, and the water level has gone down about five centimetres or so, it is finished! CAUTION: you do not want it to sit too long it could explode.

11. Refrigerate.

12. Enjoy!!

What is going on?

In this activity, you tried a little bit of home brewing in order to make root beer! In order to make any soda, you need a heavily sugared base which you made using water and white sugar. The next step you added the yeast, and let it sit out for a few days – something kind of magic happened.

A process called fermentation. As the root beer ferments, the yeast eats the sugars and as this is working its magic, a gas called carbon dioxide also begins to be produced. This is what makes your root beer fizzy when you drink it. It is also what could cause your bottle to explode if you leave it for too long – too much pressure will build up in the bottle and it will have nowhere to go, causing the careful.

Patty Rooks, senior scientific consultant Praxis Science Outreach Society. Praxis has moved! We are very fortunate to be located in the Community Futures Entre Corp Building at #202 556 Fourth St. SE, Medicine Hat, Alberta, T1A 0K8. For all your science needs, please email praxis@praxismh.ca.

31
-30