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126 W i n e s & V i n e s n O V e M B e r 2 0 1 4 WineEast Winemaking and the pH will be lower and the acidity higher. For older vines that have deeper roots with less growing tips, these are the things that have modified the potassium available over time. Higher crop levels, early harvesting and dry soils can lead to higher titratable acidity and lower pH lev- els. Soil moisture content at the growing tips, not evaporation, is probably a critical factor to consider in terms of the avail- ability and the time of potassium uptake. If a vine is overcropped, there will be less potassium per berry, resulting in a lower pH and titratable acid- ity. When the crop is reduced, there will be more potassium per berry, result- ing in higher pH and lower titratable acidity. grapes grown in challenging environ- ments can present problems of high acidity and low pH, low acidity and high pH, or, most difficult of all, high acidity and high pH. The amount of potassium uptake in challenging environments is critical in determining the titratable acid- ity and pH in the berries. Most important is the ratio of potassium to the amount of acid that you have. High in both acid and pH When a wine has high TA and low pH, the remedy is to de-acidify using calcium carbonate. For low acid and high pH, the solution is simply to add tartaric acid. In situations where grapes are high in acid and high in pH, they contain lots of tartaric and malic acids. Because there is also a lot of potassium, the pH is high as well. In de-acidification, the winemaker needs to shrink the tartaric and malic pool, which will pull potassium out and bring a proton back in. In this case, the winemaker has to do two things: a carbon- ate de-acidification to address tartrate and malate concentra- The effects of spring frosts or too much rain can be evident months later, when fruit arrives at the winery. Roger Boulton is a professor and chemical engineer. w w w . w i n e s a n d v i n e s . c o m MARKET DATA AND ANALYSIS Wineries DtC Shipments Off-Premise Sales Flash Sales WINES VINES ANALYTICS Market Research for Wineries and Suppliers