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 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.