I like 'em crisp and tart (and cold), so Granny Smith from the refrigerator is my default. I recall Newtown Pippins being a bit sweeter than I like, but I unde

I like 'em crisp and tart (and cold), so Granny Smith from the refrigerator is my default. I recall Newtown Pippins being a bit sweeter than I like, but I understand they vary. Is there a time of year, or another way to select for tartness?