YEAST PITCHING & INOCULUM BASIC CALCULATOR 2025

Propagation of yeast biomass as the source of inoculum for ethanol fermentation process has a critical impact on overall process yields and process efficiency. While batch yeast propagation at low density operations are the standards typically associated with high gravity Simultaneous Saccharification and Fermentation processes it is of critical importance to ascertain yeast performance economic impact and sustainability of ethanol manufacturing in challenging commodity economy. FermAxiom LLC has developed tools and practices that allow quantification,  validation and optimization of yeast performance and strain and technology options available for the industrial ethanol manufacturers. To enhance process quantification and understanding of scientific principles as well as data interpretation the web enabled calculators are provided.  

The advanced version of Yeast Pitching & Inoculum Calculator – Ethanol Fermentation incorporates some more advanced calculations as well as graphical representations of fermentation associated biomass cultivation processes. Also, the cost structure of each process is included to provide a comparative analysis of benefits associated with each process. The advanced version is available upon request.  

BASIC CALCULATOR STRUCTURE

The calculator is designed with three distinct sections that correspond to the technology selection:

1. Ethanol Fermentation - Direct Yeast Pitching & Inoculation
2. Ethanol Fermentation & Yeast Biomass Propagation
3. Ethanol Fermentation & Pre-Fermentation & HDYC (ADVANCED CALCULATOR)

Each of these technologies offers its own benefits and limitations and directly dictates the particular yeast management strategy to obtain its maximum ethanol biocatalytic activity. In each case either natively produced yeast inoculum can be used or commercial yeast products in the form of Cream Yeast (~5-20 % d.s.) or Active Dry Yeast (~94-96 % d.s.). If commercial product is used implementation of Ethanol Fermentation with direct yeast pitching as inoculum requires most yeast and most often is financially prohibitive and performance of such inoculum is often not optimal. In contrast the traditional technology where ethanol fermentation process is dependent on yeast propagation uses significantly less yeast inoculum and if commercial product is used it offers some incentives because of its simplicity and broad acceptance. Yet is should be understood that while the term propagation is used to describe these industrial cultivation processes it is not the most accurate description of this process as yeast growth is still strongly dependent on respiro-fermentative metabolism. The advanced option where ethanol fermentation is combined with pre-fermentation and production of high-density yeast culture offers the most robust technology solution where high-quality yeast inoculum with controlled composition and metabolic activity can be produced for the optimal ethanol manufacturing under variable industrial process conditions. HDYC is also the least expensive option in terms of operation and ingredient usage (including if used the commercial yeast inoculums) in aition it offers an unparallel performance boost for any yeast strain. In terms of general yeast usage: Ethanol Fermentation dependent on Direct Yeast Pitching & Inoculation requires about 20X yeast that is required as inoculum if Ethanol Fermentation process is combined with Standard Yeast Biomass Propagation process (assuming about 4-5 yeast generations during yeast biomass propagation).