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Is that Yeast Good?

Cooking tips for the caring cook.


Your yeast may have an expiration date on stating it has expired, but if you have stored the yeast in the refrigerator, or better yet, in the freezer where it will remain active even longer, it may still be good beyond the stated expiration date on the package.

To test your yeast:

  • Proof your yeast by adding about 1/2-cup warm water to a measuring cup. To be truly accurate beyond a doubt, use a candy thermometer to check the water - it should be 110 to 115 degrees.
  • Add 1/2 to 1-teaspoon sugar and 2 teaspoons yeast (or one entire packet yeast). You should be seeing, at this point, 3 almost equal levels: the bottom level will be the sugar and yeast, the middle level cloudy water and the top level a film of yeast.
  • If foam and bubbles form within 10 minutes, then the yeast is still active (alive). The mixture will be approximately half milky looking water and half foam.

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