Brewing a Yeast Starter

A starter is an essential step in the homebrewing process, as it allows for the propagation of additional yeast cells before adding them to the fermentation. This ensures a healthy and vigorous fermentation, leading to better tasting . In this article, we will guide you through the process of creating a yeast starter for a 5-gallon batch of beer.

To begin, you will need the following ingredients and equipment:

– 100ml of
– 10 grams of Dry Extract (DME)
– 2 teaspoons of sugar
– 2 packets (14 grams) of yeast (or 1 tablespoon if using bulk yeast)
– A glass or flask to create the starter

Firstly, add the 100ml of water to the glass or flask. It is important to use a container that is sanitary, as any unwanted bacteria or contaminants can negatively impact the fermentation process.

Next, add 10 grams of DME to the water. DME acts as a food source for the yeast, allowing them to multiply and grow. It is recommended to use a ratio of 10 grams of DME for every 100ml of water, as this provides an optimal environment for yeast growth.

To further enhance yeast growth, add 2 teaspoons of sugar to the water and mix thoroughly. Sugar provides an additional source of energy for the yeast, promoting a healthy fermentation.

Once the sugar and DME are fully dissolved in the water, it's time to add the yeast. This can be done by pouring in 2 packets of yeast or 1 tablespoon of bulk yeast. It is important to choose a high-quality yeast strain that is suitable for the style of beer you are .

Swirl the glass or flask gently to mix in the yeast with the sugar water. This ensures that the yeast is evenly distributed and can begin to feed on the sugars and DME.

Now, allow the glass or flask to sit undisturbed for approximately 20 minutes. During this time, the yeast will begin to activate and multiply. You will notice the mixture doubling in size, indicating a successful yeast starter.

Once the yeast starter has doubled in size, it is ready to be added to your fermentation. It is recommended to pitch the entire yeast starter into the fermenter, as this will provide a healthy population of yeast cells to kickstart the fermentation process.

By creating a yeast starter, you are ensuring that your beer has a strong and healthy fermentation, leading to better flavors and aromas in the final product. This simple yet crucial step in the homebrewing process can greatly improve the quality of your beer.

Creating a yeast starter is an essential step in the homebrewing process. By using a combination of water, DME, sugar, and yeast, you can propagate additional yeast cells before adding them to the fermentation. This promotes a strong and healthy fermentation, resulting in better-tasting beer. So, next time you brew a batch of beer, don't forget to create a yeast starter to enhance the quality of your brew. Cheers!

What Is The Ratio For A Yeast Starter?

The ratio for a yeast starter can be determined by the amount of dry malt extract (DME) to water. A commonly used ratio is 10 grams of DME for every 100 milliliters of water. This means that for every 10 grams of DME, you will need 100 milliliters of water. Here is a breakdown of the ratio:

– 10 grams of DME
– 100 milliliters of water

To create the yeast starter, simply mix the DME and water together. This ratio provides a suitable environment for the yeast to propagate and grow, allowing for a healthy and active yeast starter. It is important to note that this ratio can be adjusted based on the desired yeast cell count and the specific requirements of your brewing recipe.

recipe for yeast starter

What Is A Typical Yeast Starter?

A typical yeast starter, commonly used in homebrewing, is a process for cultivating additional yeast cells from an existing yeast culture. The purpose of this is to increase the yeast population before introducing it into the fermentation process. The steps involved in creating a yeast starter are as follows:

1. Sanitization: To maintain a sterile environment, it is crucial to sanitize all the equipment that will come into contact with the yeast starter. This includes the flask or container, airlock, stir plate (if used), and any other utensils.

2. Malt Extract Preparation: Malt extract, which is a concentrated form of malted barley, is commonly used as a nutrient source for the yeast starter. It is typically sterilized by boiling it in water. The sterilized malt extract solution serves as the medium for yeast growth.

3. Inoculation: Once the malt extract solution has cooled down, the yeast culture is introduced to it. The yeast culture can be obtained from a previous batch of beer, a yeast slurry, or a commercial yeast packet. The yeast is carefully added to the malt extract solution to avoid any contamination.

4. Aeration: Yeast requires oxygen to reproduce efficiently. This can be achieved by shaking the flask vigorously or using an aeration system. Providing sufficient oxygen helps the yeast cells multiply rapidly, leading to a larger yeast population.

5. Fermentation: The yeast starter is placed in a temperature-controlled environment, typically around 68-72°F (20-22°C). The yeast cells consume the sugars present in the malt extract, producing carbon dioxide and . The fermentation process allows the yeast cells to grow and multiply.

6. Cold Crash and Decantation: After the fermentation is complete, the yeast starter is cooled down to near-freezing temperatures. This causes the yeast cells to settle at the bottom of the container. The excess liquid, known as the spent wort, is then carefully poured off or decanted, leaving behind the concentrated yeast slurry.

7. Pitching: The yeast slurry obtained from the yeast starter is now ready to be added to the main batch of beer or other fermentation. The increased yeast population ensures a healthier and more vigorous fermentation process, resulting in improved flavor and attenuation.

Yeast starters are particularly beneficial for high-gravity beers, where the initial yeast cell count may not be sufficient to handle the higher alcohol content. By propagating more yeast cells through a starter, the fermentation process becomes more robust and reliable.

Yeast starters play a crucial role in homebrewing by providing a controlled environment for yeast propagation, leading to healthier and more active yeast cells, which ultimately enhances the fermentation process and produces better-tasting beer.


Creating a yeast starter for your homebrewing endeavors is a simple yet crucial step in ensuring a successful fermentation process. By following the recommended ratio of 10 grams of DME for every 100ml of water, you can easily scale up this recipe to accommodate a 5-gallon mash.

To begin, start by adding 2 teaspoons of sugar to the water and mix it thoroughly. This sugar serves as a food source for the yeast, allowing it to thrive and multiply. Next, add 2 packets of yeast, which is approximately 14 grams or 1 tablespoon if using bulk yeast. Swirl the glass to ensure that the yeast is well incorporated with the sugar water.

Allow the glass to sit undisturbed for about 20 minutes. During this time, the yeast will undergo a process called fermentation, where it consumes the sugar and produces carbon dioxide and alcohol. You will notice that the glass will double in size as the yeast population increases.

By creating a yeast starter, you are essentially propagating additional yeast cells, which will help ensure a healthy and vigorous fermentation when added to your main fermentation vessel. This process is particularly beneficial for high-gravity beers or when using older yeast cultures.

A yeast starter is an essential step in homebrewing that allows you to cultivate and multiply yeast cells before introducing them to your main fermentation. By following the simple recipe and allowing the yeast to multiply, you can greatly enhance the fermentation process and increase the chances of a successful brew. So, don't forget to incorporate this important step into your brewing routine and enjoy the fruits of your labor with a delicious, well-fermented beer.

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Thomas Ashford

Thomas Ashford is a highly educated brewer with years of experience in the industry. He has a Bachelor Degree in Chemistry and a Master Degree in Brewing Science. He is also BJCP Certified Beer Judge. Tom has worked hard to become one of the most experienced brewers in the industry. He has experience monitoring brewhouse and cellaring operations, coordinating brewhouse projects, and optimizing brewery operations for maximum efficiency. He is also familiar mixology and an experienced sommelier. Tom is an expert organizer of beer festivals, wine tastings, and brewery tours.