Hi and welcome. First, flavor is very subjective so it all depends on how you define "zesty". Neither of the two varieties is especially noted for its flavor but if you were content with them in the past and this year is different then the contributing factors are all environmental and growing conditions in source.

Yellow shoulders and inconsistent ripening is caused by extreme heat temperatures. As the internal temp of the fruit rises the development of lycopene is slowed and stopped and nutrient distribution throughout the fruit is also affected negatively. If the plants are pruned or positioned so that the fruit is heavily sun-exposed the problem increases. Other contributing factors can be too little water (which also contributes to the hard cores), pests, disease issues, etc.

Hard cores - again insufficient water and/or pronounced inconsistency in the available soil moisture. It is apparently most common in the juicy/beefsteak varieties. Use of excess fertilizer, overly hot weather, or even severe fluctuations in air temps can contribute to the problem.

Flavor would likely also be affected of course.

So it isn't a soil additive solution. Can you tell us more about the growing conditions you are using, fertilizer, in-ground or in containers, the weather, watering regimen, pruned or unpruned, incidence of sunscald, etc.?

Dave

In ground. I used 1 application of triple 13 when I planted them, about a tbsp per plant, then twice I used Miracle Gro, about a #2 tin can full. Weather has been pretty hot, live in east-central MS and there was more rain this year than normal, only watered once early, may have needed another. Unpruned and in cages. They have about done their thing, any kind for late hot weather for this late in season?

Steve34, where are you at in the US? Here in VA, I've been joking I'll never have to water again, because of all the storms here. The peaches at the farmer's market were "watery" tasting this year--they were saying it was from all the rain. I've heard the same could be said for tomatoes when it's been very wet as well.

I'm apprehensive for my seven varieties of tomatoes I'm growing. But, I'll just see at harvest time (lots of green right now, but no red yet). But heck, can't be worse then the grocery store.

*Grow my Romas, grow!*

Oops! You just said. I really think it could be the excess rains. :/ Not sure there's anything we can do about mother nature this year.