I have a bread machine and when i follow the recipe putting boiling water, sugar, one packet of yeast, then let if foam for 15 minutes the yeast still isn't rising. What should do differently?

2 Answers 2


Never use boiling water with yeast!
Using boiling water almost guarantees instant death.

Baker's yeast is a live organism, a unicelluar fungus saccharomyces cervisiae, very closely related to and in fact bred from brewer's yeast. And yes, it's alive even in those dried granules in small packages or boxes. It's metabolism digests carbohydrates and produces CO2 (what we want in baking because it creates a light and fluffy dough) and alcohol (of interest in brewing and winemaking).

Yeast is heat sensitive and while it will happily grow and multiply in lukewarm water, it starts to die at about 45 to 55 degrees C. Note that yeast does even grow at refrigerator temperatures, albeit slowly, in fact, many bakers prefer the long and slow fermentation over a quick warm rise.

This question/answer discusses temperature thresholds in detail.

If your recipe suggests the use of boiling water, it's faulty and I suggest simply using lukewarm water instead or finding another recipe altogether.


You might want to try active dry yeast. It generally works without needing to 'prime' it with warm water and sugar. I add it directly to my flour/salt mixture, mix it all up and then add whatever liquids and it bakes wonderfully.

I keep a big container of it in my freezer, even after multiple years in there it still works well.

For 'normal' yeast the water should feel hot to your hands, that's plenty warm enough to get it started.

  • "Feel hot" might be misleading - I can handle temperatures in the 45-50 C range easily, which would hurt if not kill the yeast. "Body temperature" or "lukewarm" is plenty enough, in my undestanding of decribing temperatures.
    – Stephie
    Oct 5, 2015 at 9:51

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