TY - JOUR T1 - Ammonia Content of California Grapes JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 213 LP - 220 DO - 10.5344/ajev.1969.20.4.213 VL - 20 IS - 4 AU - C. S. Ough Y1 - 1969/01/01 UR - http://www.ajevonline.org/content/20/4/213.abstract N2 - The ammonia content of grapes was discussed along with possible paths of assimilation. Variations due to years were found associated with climate changes. Varieties, rootstocks, and areas caused distinct variations in ammonia content. The changes were less pronounced it ratio of ammonia to total nitrogen was considered. The effect of maturity was especially pronounced in fruit from the warmest areas.Grape juice ammonia values in 310 determinations ranged from 24 to 309 mg/l (average 123 mg/l). The ratio of ammonia to total nitrogen can be fairly constant between varieties and regions. ER -