engleski

Fermentation rate in White Riesling (Vitis vinifera L.) grape juice as affected by vineyard nitrogen fertilization

Nitrogen (N) fertilizer (urea) was applied by hand to vineyard of White Riesling grapes at rates of 0, 23, 70 or 117 kg N/ha/year from 2006 to 2009. Fermentation rate increased with increasing N fertilization, although only one of four juices from 0 kg N/ha completed fermentation, while only two of four 23 kg N/ha completed fermentation. All juices from 70 and 117 kg N/ha completed fermentation, but fermentation rate was unecceptable slow. Long fermentation time was strongly correlated with low free amino nitrogen levels in all juices, varying from 13 to 40 mg/L. Nitrogen fertilization rate affected higher titratable acidity.

fermentation rate; fertilization; grape juice; nitrogen

nije evidentirano