Proofing Yeast

Do you know why we proof yeast? Simply to check if it is still alive.

Yeast converts sugar into alcohol and carbon dioxide, which allows bread to rise. So, if you know your yeast is alive and well, you can use it in your recipe without first proofing it. The conversion will occur while the dough is rising. However, if your yeast has been opened and used already, you need to proof it to make sure it is still alive before you use it. The best way to store yeast is in the freezer. Yeast will last for up to 6 months if it is stored in an airtight container. I have still been able to use yeast that has been stored for longer – you will know how viable it is after you proof it. Yeast will last about four months if stored in the refrigerator. Pull it out and let it come to room temperature before you use it.

Generally, you only need to proof active dry yeast or fresh yeast, not rapid rise or instant yeast. The key to proofing your yeast is lukewarm water and some sugar. The water should be around 100° F (40° C). You can use a thermometer if you have one on hand, or for all of you who have warmed up a baby’s bottle before, remember when you sprinkled some of your child’s milk on your wrist to test if the milk was warm enough? – that will work. That’s the temperature you want your water to proof your yeast.

Whisk in 1 tablespoon (15ml) of sugar or honey with the amount of water called for in your recipe. [If you want to play around with proofing yeast, use about ½ cup (115ml) of water.] Yeast needs sugar – not a sugar replacement. The yeast eats sugar to convert it into alcohol and carbon dioxide. The alcohol and carbon dioxide create those wonderful pockets of air in your bread as it bakes.

After gently mixing the yeast, just let it sit on the counter to rise. It will only take about 5 to 10 minutes. The yeast will create this pleasingly creamy foam on the water’s surface. You will smell the fermentation. When you see the foam, you know your yeast is alive! You are ready to use it in your bread. If you do not see any foam, it won’t matter if you let it sit any longer. That yeast is dead and will not make your bread rise. It is time to purchase some new yeast.

Yeast likes a cozy house, too – around 70° to 80° F – so keep that in mind with your house temperature too. If your house temp is lower than that, you should place your yeast in your oven with just the light on – that will create a cozy environment for it to thrive in.

Yeast Variety Conversions