NEW DOWNLOAD: Yeast Management & Repitching Guide

The following excerpts are from our newest e-book, Yeast Management & Repitching, which is now available for download! 

Harvesting and repitching yeast is one of the most cost-effective ways to boost brewery efficiency — when done right.

At Escarpment Labs, we’re passionate about helping brewers get the most out of their yeast. Our newest guide breaks down the key principles behind successful yeast reuse, helping you stretch every cell for maximum flavour, reliability, and savings.

You don’t need a microscope or advanced lab setup to get it right — just the right knowledge, a little preparation, and some brewer’s intuition.

Healthy Fermentation Formula

"Everything should be made as simple as possible, but no simpler."

— Albert Einstein (paraphrased)

This quote is commonly used throughout education. It means making something as easy to understand as possible without losing essential information, meaning, or accuracy.

You have likely seen pitch rate formulas such as:

0.5-1 million cells/mL/°P (for Ales)

This formula was developed in large breweries by academics who were looking to increase or stabilize beer throughput and consistency, and were generally only making 1-2 styles of beer. Due to this, the calculations that were created from these environments have certain unstated biases.

The above formula is simple, but it has been made too simple, as to lose essential information, meaning and accuracy. It does not follow Einstein's standard. It needs to factor in more variables.

Why are more variables uncommon?

The main reason that many of the variables that also impact healthy fermentations are not discussed is that they are not easily quantified.

For example, if we have a group of people in a room, it’s easy to count how many there are. But if I asked you to rank them from healthiest to least healthy, it would be much harder—and nearly impossible to assign each person a precise health value.

Fermentation Variables and Why They're Present

1. Cells Pitched

   The number of yeast cells pitched into wort is the cornerstone of successful repitching. Too few or too many can cause off-flavors and/or a sluggish attenuation. Not knowing how many cells you’re pitching is one of the fastest ways to invite fermentation problems and compromise beer quality.

   Many breweries are under the impression that it is impossible or reckless to repitch yeast without a microscope and a hemocytometer. Although cell counting is recommended for more accurate results, you absolutely can use other methods to measure the amount of yeast you have. Settled Yeast Volume (SYV) is one such method; we cover SYV in more detail in Section 3.

   To alter this variable, we simply add more or less yeast.

   Why not just always over-pitch?

   It is always better to over-pitch than under-pitch, but you run the risk of under-nourishing the cells if done consistently or to the extremes.

2. Cell Health

   The healthier a cell is, the more stress it’ll be able to handle (lack of nutrition, under-pitching, etc.) without any undesirable changes in fermentation performance, flavour profile, or viability during subsequent repitches.

   Yeast are just like people, it is difficult to determine if they are healthy or not. One of the best ways to assess health in either case is to observe them.

   For humans, we measure our weight, sleep, blood pressure, how much exercise and most importantly, how we feel. For yeast, we monitoring fermentation performance (speed, total time and completeness), cell physiology (size, shape and viability) as well as harvest time, storage time and times repitched.

   We can’t ask yeast how they feel (humans lie about it too) but by paying attention to these attributes, we can better understand yeasts health and predict it’s performance just like we would a human.

3. Wort Stress
   

   Our diet plays an important role in our health, and the same is true for a yeast.

   If we have a balanced diet with proper nitrogen (FAN for yeast, protein for humans), carbohydrates (sugars), vitamins, and minerals, then we generally see great health. That assuming nothing is toxic or stressfull in the enviornment.

   Many different things can stress yeast out. These include:

   • Wort Gravity: High-gravity wort contains large amounts of dissolved sugars and proteins that create osmotic stress, pulling water out of yeast cells and making it harder for them to function properly. Yeast needs to spend extra energy to maintain their cell homeostasis due to the increase in density.
     
     

   Note: This is the same stress that helps keep jams and other viscous foods more microbially stable.

   • Nutrient Deficiency: Like humans, yeast requires not only adequate nutrients, but the correct ratios for optimal health. If the cells are lacking a certain nutrient, their health will suffer. However, unlike humans, who have larger reserves of essential nutrients, yeast feels the impact much sooner.
     
     
     • Nutrient deficiency is influenced by pitch rate. Example: imagine you are planning dinner for 10 people, but 20 show up. Each person will be underfed or undernourished. If we overpitch, this is what we are doing - each cell consumes less and finishes the fermentation hungry.
       
       
       • For more information on this topic, see our “Nutrition Guide” https://escarpmentlabs.com/blogs/resources/download-yeast-nutrition-guide
         
         
   • Temperature/pH: Not normally a stressor seen in brewing yeast except when making sour beers. More common in other types of fermentations.
     

      

   • Toxins: Some compounds are toxic to yeast cells, such as alcohol, which is naturally produced by yeast during fermentation! Yeast can be especially stressed in high-gravity fermentations: they start in an osmotically stressful high-sugar wort and transform it into a high-alcohol beer.

     • Other compounds that are toxic to cells are hops (60+ IBU & dry hops), caffeine, herb/spice polyphenols.

Healthier Yeast Is More Important Than “Correct” Pitch Rate

The healthier the cells, the less important pitch rate becomes. As mentioned in our previous section, you’re probably familiar with a pitch rate that looks something like this:

This is correct; however, it is missing an important variable: the yeast health.

The healthier our yeast cells are, the less we need to worry about pitch rate. Each cell can tolerate either more stress or less nutrition without becoming damaged.

The Takeaway

Healthy yeast makes better beer.

A balanced approach to repitching — one that considers cell health, stress, and environment — leads to consistency, cost savings, and better flavour.

 

Our Yeast Management & Repitching Guide breaks down these fundamentals with practical, brewer-tested methods that don’t require a microscope or a full lab setup.