I want to make sure I understand what you mean by "drier." Is it literally drier, like the mouthfeel leaves you feeling it's, well, drier than you would like? Pasty, something like a dry chevre? Crumbly texture? Acidic? Too hard?
If we're talking crumbly, on pH. I have no experience with washed curd, so this is pure extrapolation, conjecture, take it for what you will. In trying to achieve a nice elasticity in an alpine curd, it's more important what your drain pH is, v. the terminal pH. Your vat acid curve will largely determine how much colloidal calcium, the micelle calcium phosphate, is lost to the whey. Lower vat pH means more calcium phosphate solubilizes, and that means less in the curds. That results in a less elastic, more crumbly curd.
I wouldn't think this is an issue, though, in a washed curd, depending on how much lactose you do wash away, so a bit of me wonders that it might not be so much an acid issue, as a physico-chemico issue - temps, cut size, ramp and cook schedule, etc.
That said, managing acid has been for me the steepest learning curve to date. In early tommes - not so much hard, but too crumbly (i.e., a hard cheese obviously can have plenty of elasticity, as in the hard alpines)...that, I can almost aver, is always acid, for me.
