How to Test Yeast to see if it’s still Good

posted by Jessica Hylton on May 13, 2020 (last updated Dec 11, 2020) 31 comments »

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How do I test yeast and is it still good or fresh? Find out easily with this quick and simple 10 minute test!

Here’s a question I often ask myself: “Is my yeast still good?!”. Yeast is a living thing, and the bread and buter of your baking recipes so you always want to ensure it’s good before using it, else your recipe won’t work. I’ve been baking for over 10 years, and the truth is that unless you test your yeast, you won’t know. Fortunately, it is very easy to test yeast in just 10 minutes, and will make all your baking projects that much easier. I realised that if I’m asking this, maybe many of you are too. Here’s how to check if your yeast is still good.

What is Yeast?

Yeast is a leavening product that is alive and that you add to your dough to make it rise. In this post, I’ll be referring to instant yeast and active dry yeast. Yeast needs the correct environment to properly grow and multiply, thus helping your dough to expand and create beautiful baked products. This environment (known as a sympathetic environment) refers to the temperature of its surroundings such as your kitchen, the temperature of the liquid it’s in, and the food (sugar or starch) that you add to the dough to make it rise as it bakes.

Active dry yeast is a dormant form of yeast made up of live yeast cells surrounded by dead cells. Its granules are large, and as the name suggests you need to “activate” your dry yeast. When using active dry yeast, the yeast will need to be dissolved in some warm water with sugar (aka, exactly what are doing today) before using it in the recipe. This process is called proofing.

Instant yeast is made up of finer granules and does not need to be proofed before it. You can mix it right into the dry ingredients. It’s also made up of 100% living cells and as such tends to be seen as more powerful than active dry.

What yeast to use?

I recommend using the yeast that your recipe calls for. For instant, I use SAF Instant Yeast. For active dry yeast, I love Bob’s Red Mill. They are both very affordable, is affordable in large quantities and last very long.

How to Test Yeast to see if it is Good

To test yeast, start with 1/2 cup of warm water that is about 100°F. You want your water at this temperature because it’ll be warm enough to activate your yeast, but not hot enough to kill it. To emphasize, you do not want boiling water nor too hot water. I recommend using a food thermometer or a candy thermometer. If you don’t have one, basically you don’t want water that’ll be too hot to touch.

Then, add in 2 1/4 teaspoons room temperature instant yeast (or active dry yeast) and 1 teaspoon sugar. The sugar feeds the yeast and provides what my husband (the scientist) calls “activation station!”. Stir it all the combine for about 15 seconds until combined and then leave it alone for about 10 minutes. After even just a few minutes, you should start to see the top bubble and lightly bloom or foam.

After 10 minutes, the yeast should’ve doubled or tripled in size and should be high up. The first container I tested this in, I completely forgot that I was testing and it bubbled over onto the counter! This is all good news – your yeast is fresh!

If your yeast does nothing and you added the right temperature of the water, your yeast is dead. Toss it, and get some fresh yeast.

Happy Baking! If you want a few yeast recipes to start off with here are some of my favourites:

How to Store Your Yeast to Keep it Fresh

The best place to store your yeast is in the freezer or the fridge. I keep mine in the fridge, but the freezer puts a pause on the yeast’s expiry date, making it last much longer.

How long can you store yeast?

If using active dry yeast, I recommend going by the date on the bag. Instant yeast can last for years in your fridge or freezer.

I hope this post on how to test yeast helps friends and that you find it useful! Happy Baking!