If you grow or buy Heirloom tomatoes like Brandywine, Cherokee Puple, Paul Robeson, Aunt Gertis Gold or any of the thousands available heirloom tomatoes they will have a perfect sweet-sour-acid balance.
If tomatoes are sour most likely they were pcked too early and shipped to a store before te sugars developed or Brix reading.
BTW NEVER lace tomatoe in the frig as it reak down their nature sugar and sour acidic taste --- blah tomatoes often with a cardboard texture.
shantihhh says :