Enhancing Your Brew: The Science of Effective Yeast Propagation

As the craft brewing industry continues to change, we’ve noticed a trend: more and more brewers are using our homebrew packs or small (1-2 hL) pro pitches for professional purposes. While we’re thrilled to see such enthusiasm for our products, we’d like to share some insights on yeast propagation to help you achieve the best results possible. Proper yeast propagation is key to brewing consistent, high-quality beer, and understanding the essentials can make a significant difference in your brewing process.

The Basics of Yeast Propagation

Yeast propagation is the process of growing yeast cells in a controlled environment to build up a sufficient quantity for fermentation. This involves providing the yeast with the necessary nutrients and conditions to thrive. Here are some key factors to consider:

1. Nutrient Requirements:

Yeast nutrition is CRITICAL in propagation and poor nutrition leads to poor performance and lost tank time.

Yeast requires malt sugars, complex nitrogen, and pH buffers for optimal growth. Using wort with a concentration between 10-15ºP and at least 200ppm of free amino nitrogen is ideal. While malt extracts (LME or DME) can be a good starting point, they often lack some essential nutrients. Supplementing your propagation wort with additional nutrients can significantly enhance yeast health and performance. Yeast Lightning at a dosage rate of 28g per 100L of propagation wort will typically help improve yeast propagation. 

2. Aeration:

Continuous aeration using sterile filtered compressed air is recommended during propagation. This ensures that the yeast receives a steady supply of oxygen, which is crucial for healthy growth. Pure oxygen can also be used at the start, but continuous use can be wasteful and costly.

3. Temperature Control:

Maintaining the right temperature is critical for yeast propagation. The ideal range is between 20-30ºC. Lager strains perform best at the lower end of this range, while kveik strains thrive at the higher end. Propagating within this range helps ensure robust yeast health and effective fermentation.

4. Quality Control & Consistency:

Yeast propagation is easy to get right once. Repeatedly achieving perfection is difficult. All it takes is one bad batch to erase all the cost savings.

At the very least, we strongly encourage performing cell counts and viability measurements when propagating yeast in-house in order to control the pitching rate of your beers. If the yeast growth is inconsistent, the pitching rate will be inconsistent, which in turn could make your beer inconsistent. 

Implementing an in-house lab for quality control is essential for breweries propagating yeast. Regularly performing microbiological quality control analysis (plating and PCR) on your propagations ensures repeatable and high-quality beer. It helps identify any potential issues early on, preventing costly mistakes down the line. Note also that 

5. Labour Costs/Economics:

On the surface, propagating yeast in house is a way to save money in the brewery. However, it is important to factor in labour costs to the total yeast cost when propagating yeast in your brewery.

No matter how optimized your system is, propagating yeast will always require a person to do the extra work. What's more, yeast doesn't sleep, and propagations might need monitoring on evenings and weekends. It is critical to factor in the labour costs associated with propagation when considering this option versus simply purchasing full-size yeast pitches. When troubleshooting inconsistent fermentations and evening/weekend yeast checks are added in, the savings might not be so large. This is especially true if inconsistencies in propagation lead to wide swings in final gravity, attenuation, or flavour. 

Factors impacting the economic decision to propagate yeast in-house:

1. How many hL/bbl of beer do you produce in a year? Typically, propagation is best suited to larger breweries. 
2. Do you have specialized staff who can be trained in yeast propagation? 
3. Do you have a laboratory with equipment and staff capable of checking your yeast and beer for contaminants? 
4. What is your labour cost per hour including overheads (taxes, emploment insurance, health benefits, etc)? How many hours total does each propagation require?
5. How many different yeast strains do you use in a year? With propagation, it's best to learn the ins and outs of 1-2 strains first before branching out, because every strain is different. 

Many brewers will find that purchasing full-size yeast pitches propagated by experts with 10+ years experience will produce more consistent results at an acceptable price versus in-house propagation.

But, we're here to share our knowledge. If you insist on propagation, we've got you. Read on! 

Professional Pitches vs. Homebrew Packs

While our homebrew packs are fantastic for smaller batches and experimental brews, we encourage professional brewers to consider using our professional pitches when propagating yeast in-house. With professional pitches, there is more control over shelf life, and they come with the added benefit of expert advice and feedback from our team when you order. 

The price of a 1-2 hL pro pitch is typically quite similar to ordering multiple homebrew packs and also ensures less single-use plastics are consumed.

If cost is a concern, we encourage brewers to integrate repitching into their practices. The cost of each brew reduces every time you reuse a yeast, making it very cost effective for brewers. Repitching often offers other practical benefits, too: increased fermentation performance, flocculation, and enhanced flavour compound production. This improvement is most often observed in the 2nd to 4th generation of the yeast as the yeast adapts to your brewery. This can be extended through the use of a complete beer yeast nutrient such as Yeast Lightning (at a rate of 4 g/hL or 5g/bbl in wort). 

To explore how to use professional pitches or repitch in your space, you can contact our team (help@escarpmentlabs.com), or visit some of these resources for more information:

YEAST REPITCHING AND HANDLING RESOURCES

Using professional pitches can provide peace of mind and contribute to more consistent results in your brewing process.

Enhancing Yeast Propagation with Nutrients

One way to ensure the success of your yeast propagation is by using nutrient supplements. Nutrients specifically deliver the vitamins, minerals, and amino acids that yeast requires for healthy growth. In particular, nutrients are beneficial when using malt extract (DME or LME) as the propagation medium base. By incorporating these nutrients into your propagation process, you can achieve healthier yeast, more consistent fermentation, and ultimately, better beer.

Why not try Yeast Lightning?

Save on time & risk by using a specialized nutrient designed specifically for beer yeast, like Yeast Lightning! It can be used for both propagation and beer fermentation. 

By providing essential vitamins, minerals, and amino acids, Yeast Lightning promotes healthy yeast growth and activity, leading to improved flavour profiles and reduced fermentation times. For brewers, this means greater control over the brewing process, and the ability to produce high-quality, unique beers with each batch. 

For propagation, we recommend adding Yeast Lightning to the propagation wort at a rate of 28g/100L. 

LEARN MORE ABOUT YEAST LIGHTNING

Now, You're Ready for Propagation Perfection!

Yeast propagation is a critical component of the brewing process that, when done correctly, can lead to consistently high-quality beer. By understanding the basics and incorporating nutrient supplements, you can significantly improve the health and performance of your yeast. Whether you’re using homebrew packs or professional pitches, these tips will help you optimize your yeast propagation and elevate your brewing process.

Looking for a Yeast Propagation Consultation?

If you are looking for expert advice to get up and running with in-house yeast propagation, you can contact us for a consultation. We can also help you run the numbers on the "make vs buy" conundrum with your yeast to help you make the most informed decision.