**Table 1** Free SO_{2} consumed and (+)-catechin (cat) and (−)-epicatechin (epi) remaining after autoxidation for 27 days. From these values is calculated the amount of each quinone that was reduced to regenerate the catechol (Figure 10). SO_{2} values on day 27 are the mean of values obtained on day 26 and 28. (+)-Catechin is taken as the monohydrate, and (−)-epicatechin as anhydrous.