How fast does yeast multiply?

In this brief guide, we will answer the question, “How fast does yeast multiply?”, discuss the best conditions to reproduce yeast, and give you some tips for the fermentation process. We will also talk about some fermentation-related curiosities and facts.

How fast does yeast multiply?

The speed of yeast reproduction depends on the type of yeast, the temperatures, and the conditions where they are growing. Usually, they grow very quickly. Instant yeast, for example, takes only about 10 to 15 minutes to be active. Dry yeast takes a little longer, about 25 to 35 minutes to be activated. 

What are the optimal conditions for yeast to grow?

To return back into activity, yeasts need food and an excellent temperature. 

If the temperature is too excessive the yeast dies. That is why when the baker`s yeast is dissolved in too warm water (above 131ºF / 55ºC) the bread does not grow. Adding high temperatures can kill the yeast, so they can not be activated. 

In very low temperatures, yeast can be “asleep”, but when they turn in a higher temperature, they have activated again. 

The optimal temperature for yeasts to develop is from 80º F to 89º F (27º to 32ºC). 

How to optimize the fermentation process of yeast?

Hygiene in Fermentation 

In every fermentation, you must have excellent hygiene and follow all the sanitary requirements. It is very important to verify all the expiration dates and put labels that indicate when each input, from flour to yeast, has been opened. 

Only use ingredients that are inspected and from suppliers who also comply with excellent hygiene standards. 

Control the temperature

As we already mentioned, the temperature is crucial for fermentation. You have to consider even the time of the year and weather conditions. However, it is possible to standardize the process of fermentation regardless of these conditions. 

Controlled fermentation chambers are a great example of this, as you just need to adjust the temperature and humidity. This will help you to get the best result in fermentation, with better standard quality.

Measure the amounts – beer production

While producing beer, the amount of yeast you add to your wort is crucial to your final product. According to the volume, the density you have, you determine your inoculum rate and the estimated number of yeast cells needed to attenuate your wort. 

Consideration should also be given to the amount of viable yeast in your liquid yeast vial or dry yeast pack. 

Yeasts always have a manufacturing date and, with each passing day, their viability drops, especially liquid yeasts that have a lower conservation rate, that is, they have a greater decay.

Let the dough rest – bread production

For making bread, it is crucial to allow the shaped dough to rest for a little longer — about an hour at room temperature — before baking the loaves. It may be essential to leave it for a while if the day is chilly. If it’s hot, a shorter period may suffice.

The dough should then be placed in a plastic bag and refrigerated for 12 hours for cold fermentation. It should be noted that the resting time will vary based on the recipe.

Curiosities and facts about yeast

  • We do not get drunk when consuming bread, as happens with beverages, because the alcohol molecules formed during fermentation evaporate with the heat of the oven when the bread is baking. And the evaporation of carbon dioxide molecules is responsible for making the bread rise until it is baked.
  • Fermentation processes are essential for the planet’s environmental balance. Anaerobic bacteria and fungi help in the decomposition of organic material on the soil, aiding in recycling.
  • Biological yeast is cells of the yeast Saccharomyces cerevisiae, a single-celled yeast fungus that can ferment carbohydrates into alcohol and carbon dioxide (CO2). 
  • The performance of yeasts during fermentation is critical to the end product’s quality. In addition to aerating the dough, the yeast creates organic acids, smells, and other substances that affect the final product’s texture, volume, color, flavor, and even shelf life.
  • Doughs for bread, toast, cake, or biscuits are complicated matrices including many components that alter yeast effectiveness. The availability of fermentable sugars is the most essential component, but other sugars such as maltose, as well as salt, minerals, vitamins, nitrogen supply, and wheat quality, must also be addressed.
  • Yeast quality is closely related to manufacturing circumstances, presentation form, and storage duration along the whole supply chain.

Other FAQs about Yeast that you may be interested in.

Can you use expired yeast?

Does nutritional yeast expire?

What can I substitute for yeast?

Is yeast eukaryotic?


In this brief guide, we answered the question, “How fast does yeast multiply?”., discussed the best conditions to yeast reproduce, and gave you some tips for the fermentation process. We also talked about some fermentation-related curiosities and facts.


Jästbolaget. “About Yeast.” Accessed December 17, 2021.

Quora. “How Quickly Does Yeast Reproduce?” Accessed December 17, 2021.

“How Fast Do Yeast Multiply? – Chocolate.” Accessed December 17, 2021.

Gastronomia, eduK. “Como fazer pão de fermentação natural? Acerte na receita!” Blog eduK | Viva da sua paixão (blog), October 6, 2020.