Low nitrogen Chardonnay juice from an Oregon winery was fermented with a series of nutrient supplements, including diammonium phosphate (DAP), Fermaid K, Superfood, yeast extract, yeast hulls and thiamine. These treatments were evaluated for their contribution to the yeast assimilable nitrogen content (YANC) of the juice, which consists of the...
Stuck and slow fermentations are a major concern of winemakers. If the levels of fermentable nitrogen in juice are too low, fermentations will be slower and may stop or 'stick' before all the fermentable sugar is utilized by the yeast. Sluggish and stuck fermentations are also sometimes accompanied by production...
Over the last several years 'stuck' and 'sluggish' fermenations have become a ma or concern of winemakers in Oregon as well as in Washington and California. During the 1996 vintage we began a preliminary survey of Oregon musts and juices at harvest and showed that many were low or marginal...
An approximation of the total yeast fermentable nitrogen content in juice or must is taken as the sum of the nitrogen available from ammonia and the alpha-amino acids present (Bisson 1991 ; Dukes and Butzke 1998 ; Jiranek, Langridge, and Henshcke 1995). Recommended levels of fermentable nitrogen needed by yeast...