Harvest (wine) of wine, winemakers would use the sugar and acid levels of the grape as a guide in determining ripeness. Early winemakers tasted the grapes to gauge ripeness. Modern winemakers use a refractometer to measure high sugar levels and °Brix or titration tests (using an indicator such as phenolphthalein) to determine the titratable acidity within the grape. In recent times there has been more of an emphasis on the "physiological" ripeness of the grape, usually in the form of tannins and other phenolics. Currently, tasting is the only way to measure tannin ripeness, which can take experience and skill to do
Straw wine scale. Grapes should originate in a single wine sub-region and reach at least 6% of alcohol. De Trafford created the first Vin de Paille to be released under the new appellation "Wine from Naturally Dried Grapes" in 1997. They use 100% Chenin blanc. A number of wineries produce straw wine, known in Spanish as "vino de pasas", including Bodegas Oliveros and Bodegas Gonzalez Palacios. Most involve a blend of two grapes, the first one usually a Muscat. Pedro Ximénez grapes are dried in the sun before being vinified, fortified and matured in a solera system like other sherries. Another straw