Why should you trust our yeast? Quality Control at Escarpment Labs

Building, sustaining, and repairing trust is a major focus for us at Escarpment Labs. You, as a brewer, put a lot of faith in us to ensure that we are giving you pure and healthy yeast that is going to make your fermentation easy and help you make a great-tasting beer.

Why is it important for brewers to trust their yeast lab?

The default state of trust when it comes to brewers and yeast isn't ideal. Some past events that happened in the industry have sowed some distrust between brewers and yeast companies. We are acutely aware of this and know that yeast suppliers need to do better in order to earn the trust of brewers.

At Escarpment Labs, we are committed to taking concrete steps to increase the trust you have in the liquid yeast you are buying. We see this as a critical piece of both our own success as well as yours. When you trust your yeast and your yeast supplier, you will feel more comfortable experimenting and innovating, in turn growing your reputation as a brewer.

How is Escarpment building trust in yeast?

As always, this starts with listening. We will listen to your problems and concerns and think up ways that we can help address them.

For example, at the start of 2021, one of our big clients asked us why we weren't regularly doing qPCR molecular detection on our yeast, since many bigger craft brewers had switched over to this technology. We didn't have a good answer, so we investigated the various options, invested in a solution, and shared our experience with them. Now they trust our yeast more. As a bonus, the new qPCR workflow is faster and less error-prone than our previous in-house PCR protocol.

Beyond quality control, fermentation performance is also critical for brewers. Stay tuned for a story about some challenges brewers had with one of our products, and the in-depth research we took on to address those challenges.

That's the bottom line here - we listen to your concerns when you tell us and find solutions.

Our qPCR system from Midwest Microbio


What does Escarpment do for QC?

It's been a while since we last talked about our quality systems, and we have some important updates!

Here is what we do for QC at Escarpment Labs:

  1. Rapid qPCR. While we had a good "endpoint PCR" method (and published a paper on it), we outgrew it and needed a faster method. Many brewers have moved toward qPCR for their QC, since the technique offers fast and sensitive results. We found that most options had critical flaws such as high per-sample costs, and inflexible support agreements. Luckily, we were introduced to Midwest Microbio whose system offers us low per-sample costs, amazing tailored workflows for every beer and yeast sample imaginable, and unparalleled support. Seriously, these people are awesome. As a bonus, we've helped them refine their yeast slurry protocol, since PCR on yeast slurry is a bit of a pain. We would love to see more brewers using this system! The more QC everyone does, the better.
  2. Agar plating. We see a ton of value in the more "old school" agar plating methods, especially when combined with qPCR (both have advantages and drawbacks). We plate yeast samples at three stages: in the starter, in the propagator, and once the slurry is harvested. We also do routine spot checks of the packaged product as well as our water and growth media. This ensures we don't miss any contaminants.
  3. Risk management system and error-proofing processes. Different products pose different risks in terms of cross-contamination. This is why since the start of Escarpment, we have had a Risk Level system that prevents a tech from handling a clean ale strain like Cali Ale after handling phenolic or diastatic yeasts in any given day. We also thoroughly sanitize processing and packaging areas at the end of each day.
  4. Separate processing of high-risk organisms. We make Brett and bacteria for beer, but we grow these organisms using a completely separate system from the main Saccharomyces equipment.
  5. Test fermentations/vitality. We test every batch in wort fermentation, and monitor gravity over time. This is an added test of yeast vitality and performance.

Here are our quality specifications for each batch of yeast (and lactic acid bacteria):

 Product Type QC Specifications
  • Homogenous appearance on WLN Agar
  • Fewer than 1:10^7 CFU on LCSM agar (for yeasts known to be LCSM negative) and MRS agar
  • No detection via qPCR for Hop Resistant Bacteria, Brettanomyces, and Diastaticus (cycle threshold = 35)
  • Viability > 95%
  • Appearance on WLN agar matches with strain library
  • Fewer than 1:10^7 CFU bacteria on MRS agar
Non-Saccharomyces/Brettanomyces yeasts (e.g. Lachancea)
  • Same as for Saccharomyces except for no detection via qPCR for Saccharomyces
Lactic acid bacteria
  • Appearance on WLN agar matches with strain library
  • Appearance on MRS agar matches with strain library
  • Fewers than 1:10^8 CFU yeast on WLN yeast


All in all, for each batch of yeast, we collect more than 40 individual data points during the process. This helps us ensure quality and consistency for you, as well as helping us analyze and improve our process.

Have questions about yeast quality control? You can feel free to contact us.

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