sweet reserve, preserved grape juice held for blending purposes, usually to sweeten, or at least soften, wines high in acidity. The unfermented grape sugars counterbalance the sometimes tart flavours of wines produced from grapes grown in cool regions such as parts of germany (where such juice is known as Süssreserve) or grapes naturally high in acidity such as riesling, ugni blanc, and colombard.

Historically grape juice was preserved simply by adding offensively high doses of sulfur dioxide.

Modern refrigeration and near-sterile filtration enable the production of sweet reserve that does not reek of sulfur dioxide. The sweet juice usually undergoes clarification and refrigeration so as to precipitate any tartrates and can be stored at very low temperatures for up to 12 months.