The latest Yeast Monitor, the Model 710, has been succesfully installed and commissioned at Chimay, Belgium, by Aber Instruments.  The customer has reported that the instrument is running well and that they are satisfied.

The monastic brewery Chimay in Belgium had a need to measure the amount of yeast to pitch into the beer after the primary fermentation. The beer is transferred after fermentation and a short period of maturation in the same vessel from the brewery site to a site in Baileux 15kms away where it is bottled and further stored as a live beer

As the beer is transferred from the fermentation vessels to a road tanker it is dosed with the exact amount of yeast to promote secondary fermentation. Care has to be taken to make sure that sufficient yeast has been dosed in as too little will produce an unacceptably slow fermentation, but too much and the excess is difficult to remove and produces a cloudy beer on the opening of the bottle.

The yeast is cropped from the fermentation vessel and stored ready for pitching. The cropping is done from a special standpipe in the base of the FV cone, which ensures that only good quality yeast cells are saved with very high viability. These are kept at 5 degC for up to 5days and a loss of around 2%viability per day is expected.  When pitching into the road tankers takes place, the viability of the yeast has to be above 85%.

The yeast is retrieved from the storage vessel and mixed with a sugar solution in a small vessel and it is here where the Aber probe measures the viable yeast  concentration.  Typically this is in the range of  125 – 140 x10⁶ cells/ml.  As the amount of green beer to be transferred is known, the volume of yeast to be pitched is calculated using the AI viable solids reading.  In conjunction with a flow- meter the Yeast Monitor ensures that the correct amount  of live yeast is dispensed correctly.

 

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