Racking
Pumping wine from one container to another to clarify it by leaving the sediment behind.

Refractometer
An instrument to estimate the sugar content of grape juice by measuring the bending of light passing through it.

Region
A geographical area less specific than a district, but more specific than a country.

Reserva
A Spanish red wine from Rioja that is aged at least 1 year in barrel and 2 years in bottle before release.

Reserve wine
In methode Champenoise, wine that is held to be blended into the cuvees of future vintages.

Residual sugar
Sugar remaining in the wine after fermentation, often referred to by winemakers as "RS".

Reverse Osmosis

Concentration of flavours by elimination of water, to keep the quality of the wine on a certain level.

Rich
A descriptor of wines that offer an abundance of flavor, texture or other sensory perceptions.

Riddling
In methode Champenoise, turning bottles of sparkling wine to collect the sediment on the closure for removal during disgorging.

Round
A descriptor for wines that seem neither flat nor angular, related to the wine's structure.

Rough
The astringent sensation in the mouth.

Ruby
A general style of red port wines that encompasses character ports, vintage port, young ruby ports, and others. All are rather sweet.