Yeast activity

Yeast is a natural product that is used in all organically leavened doughs and whose leavening power is highly dependent on age and “previous history” (transport and storage conditions). Insufficient leavening power leads to quality losses and even unsaleable faulty batches.
The aim of the research project in collaboration with Konditorei Czerr in Berlin was to develop a rapid test that can be carried out on receipt of the goods or immediately before the yeast is used in order to avoid the above-mentioned problems. This was realized in an easy-to-use measuring device “HefeCheck”, which contains a fast and automated procedure for determining the leavening power of yeasts. At the end, a recommendation for the use of the yeast is issued.

For this purpose, a yeast was defined as the standard, which was characterized by very good quality in the baking process. This was used to optimize the ingredients (sugar and yeast concentration, medium, pH value) for a standard test solution and to optimize the parameters (temperature, volume, stirring speed, sampling point) for a standard measuring method, which delivers a meaningful leavening power after just 30 minutes.
This was followed by a comparison with numerous other yeasts (fresh and dry yeasts), which showed, for example, that although dry yeasts have a significantly lower driving force than fresh yeasts, they achieve the same gas volume at the end of the fermentation process.
In order to test the suitability of yeast for special doughs, “YeastCheck” can be used to select not only the “yeast suspension” sample matrix but also “yeast dough” – and here between simple, light, medium and heavy.
The advantages of the “HefeCheck” lie in the simple integration of the test procedure into day-to-day business in order to obtain a quick and reliable assessment of raw materials and products. This enables bakers to avoid faulty batches or product batches of inferior quality, giving them a decisive competitive edge in the market.
The measuring device can also be used to modify existing recipes (e.g. to save yeast) and to develop new products.
Another possible application is the craft sector (training, education and teaching) and yeast production companies for quality monitoring.

Project partner: Konditorei Czerr GmbH & Co. KG
Duration: 01.04.2018 – 31.03.2020
Funding body: AiF Projekt GmbH on behalf of the BMWi