Sparkling wine the production of still wine with some noted divergence. At the vineyard, grapes are harvested early when there is still high acid levels. In areas like Australia, winemakers aim to harvest the grapes at 17 to 20° brix. Unlike still wine production, high sugar levels are not ideal and grapes destined for sparkling wine production may be harvested at higher yields. Care is taken to avoid tannins and other phenolic compounds with many premium producers still choosing to harvest by hand rather than risk mechanical harvesting which may split the berries and encourage maceration between the skins and juice. The
Brix prism; the result is observed through an eyepiece. The critical angle (the angle beyond which light is totally reflected back into the sample) is a function of the refractive index and the operator detects this critical angle by noting where a dark-bright boundary falls on an engraved scale. The scale can be calibrated in Brix or refractive index. Often the prism mount contains a thermometer which can be used to correct to 20 °C in situations where measurement cannot be made at exactly that temperature. These instruments are available in bench and handheld versions. Digital refractometers also find the critical