In-line Brix and dry solids measurement in yeast extraction process


Yeast extract is a processed product consisting of soluble components of yeast cells. Yeast extract is widely used in food flavoring, e.g. in soups, sauces and ready meals, as a vitamin supplement, additive and nutritive ingredient. 

Monitoring yeast extract production from fermentation to drying 

Yeast cream preparation. Yeast extract is prepared by extracting the cell contents from baker’s or brewer’s yeast. The yeast is cultivated progressively larger vessels until it reaches the capacity of  the  production  fermentators. Sugar molasses and air are added during the cultivation in order to nourish the yeast. After the fermentation, the residual sugar is removed and the yeast and washed and concentrated, and yeast cream is received.  

Autolysis. In the process of autolysis the cells will consume themselves by using enzymes from the same cells. The enzymes are freed within the yeast to break down the proteins. 

Insolubles separation. After the autolysis the insoluble part such as yeast cells, is separated from the water-soluble components by filtration. The water-soluble part constitutes the yeast extract. 

Yeast concentration and pasteurization. Water needs to be removed from the solution to achieve a desired yeast extract concentration. The final concentration must be measured continuously to ensure a high-quality product and optimal operation of the downstream equipment. The yeast extract is then dried to a fine powder or granulated particles by spray drying. 

Download the application note to learn the details on how Vaisala Polaris Sanitary Refractometer is used to continuously  monitor  different stages  of the yeast extraction process: 

  • control dilution of molasses at the initial stage with Brix concentration measurement to ensure sugar source for cell cultivation 
  • control over fermentation progress and to monitor yeast content inside the vessel 
  • measures in-line the concentration of yeast extract to ensure the target dry solids level is achieved 
  • when installed before evaporator or concentrator, the refractometer provides quality control  and helps to optimize energy consumption 

Download our application note in PDF by filling in the form.
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