Effects of juice pH and potassium on juice and wine quality, and regulation of potassium in grapevines through rootstocks (Vitis): a short review

In warm irrigated regions of Australia (such as Sunraysia), pH of grape juice often tends to be high (e.g. > 3.8). A high juice pH is undesirable for the production of quality wines as it results in wines of low quality for example, reduced colour stability and poor taste. Such a high juice pH is typically associated with a high concentration of K in the juice, depending on the scion, rootstock and location. Potassium is an essential nutrient and plant genotypes, including grapevines, differ in the accumulation of K in plant and/or plant parts. This difference in the accumulation of K by genotypes can be exploited to manipulate the concentration and content of K in plants, berries in particular for example, through selection and use of low K accumulating rootstocks to overcome the high pH affects. This paper briefly reviews the effects of juice pH and K on juice and wine quality, and the role and effect of rootstocks in the regulation of K in grapevine. This will provide a basic knowledge about the current research and key future research needed for the maintenance of acceptable quality of grape juice and wine through use of rootstocks.