Glucose was analyzed in an eletronic equipment for glucose blood analysis (Checkmate Blood Glucose Monitoring System). There was no interference from fructose or sucrose. The amount of total reducing sugars was also analyyzed, by chemical methods, and fructose was calculated, approximatelly, by the difference between the two analysis. The method was quick, cheap, reliable and easy to handle in any industry which most of the time needs fast and practical results with little preocupations with accuracy. On the other hand, the evolution of these sugars was followed, from véraison to the harvest, in five red grape varieties. The amount of glucose was higher than fructose in all varieties with the exception of Tannat. The minimum and maximum values of total reducing sugars and glucose, at the harvest, varied from 162-212 g.<img border=0 width=287 height=96 id="_x0000_i1027" src="../../../../img/revistas/cr/v31n4/a23img01.gif">¹ and 99-111 g.<img border=0 width=287 height=96 id="_x0000_i1028" src="../../../../img/revistas/cr/v31n4/a23img01.gif">¹, respectivelly.
grapes; glucose; quick methodology; wines
