What is S. cerevisiae var. diastaticus?

Saccharomyces cerevisiae var. diastaticus is a variance of S. cerevisiae that possess STA (1, 2 or 3) genes. These genes cause yeast to produce and excrete glucoamylase. Glucoamylase is an enzyme that hydrolyzes -1,4 linkages in dextrins. This then produces smaller, simple sugars that the yeast can take into the cell, which causes a very high degree of attenuation (>90%). Diastaticus is also known to be temperature and alcohol tolerant.

But when handled correctly, S. cerevisiae var. diastaticus is a magnificent yeast that can produce great flavors and beers.

What are common sources of diastaticus contamination?

Diastaticus is found in many environments. Because of this, cleaning and sanitation are highly important. We encourage you to speak with your local chemical representatives to establish a cleaning and sanitation regimen conducive to your brewery and specific needs.

Sources:
Poor Hygiene

  • Bottling/canning lines (>70% of reported cases)*
  • Brewhouse
  • Fermentation cellar
  • Storage cellar
Raw Materials
  • Yeast
  • Hop (dry hopping)

Diastaticus Fermentation vs Conventional S. cerevisiae

Saccharomyces cerevisiae fermentation vs S. cerevisiae var. diastaticus

How can I detect it?

There are a handful of options for detection of diastaticus - lets focus on plating, PCR, overattenuation tests, and monitoring

There is no selective media yet available to distinguish diastaticus. The methods provided below are other options, but each have their own challenges.