The lag time between the addition of yeast into unfermented beer (wort) and when it begins its anaerobic cycle opens the door for possible undesirable contaminants in a batch of beer.  While new yeast results in a shorter lag time, many homebrewers and microbreweries elect to reuse their yeast after washing it in order to make their brewing more economical.  A variety of washing techniques are currently used; most invoke either a weak acid or chlorine dioxide as the means by which bacteria are eliminated prior to reusing a batch of yeast.  Within the industry, no one method has gained or demonstrated a clear advantage over the others. In response to a request from a local microbrewery, the lag time associated with second-generation washed yeast was quantified in relation to the method used to wash the yeast, with a goal of determining the optimal washing method for their brewery operations.  Second-generation yeast was obtained from the microbrewery, divided, and then washed with different methods.  Viability and yeast cell counts were performed before and after the washes.  Washed samples were then introduced to identical samples of wort in order to measure the lag time associated with the onset of their production of ethanol.

Improving lag time in second-generation washed beer yeast

249th National Meeting (2015)

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