In: Chemistry
Wine Chemistry
You are given the task of analyzing a sample of grapes to determine if a vineyard is ready for harvesting
1a. The concentration of tartaric acid is critical. This can be determined by a titration experiment with 0.1M NaOH and a color Indicator (phenolphthalein. The reaction is as follows:
Tartaric acid + 2 NAOH + colorless -> 2 H0+ 2 Na" + Tartrate
You have a 0.010L sample of grape juice and after adding 0.018 L of NaOH solution the color turns pink What is the "Titratable acidity" in g/L of tartaric acid in the grape juice sample?
Steps: volume of NaOH solution moles of NaOH > moles of tartaric acid grams of tartaric acid. Then divide grams of tartaric acid by volume (L) of grape solution
1b. Acidity goes down as grapes ripen. If the answer to the previous problem is less than 7 g/L then the grapes are ready. Based on your answer are they ready?
Sza. The ather important consideration is the concentration of sugar (which increases as grapes ripen). The appropriate sugar level is about 200 g/L What is the molarity of sugar in ripe grape Juice? (molar mass of sugar is 180 g/mole).
26. Amore commonly used unit in wine-making is Brix 1 brix = 10g/Of sugar. It your grape juice sample has a brix reading of 10, is it ready to harvest?